Families of this order include the dogs, bears, seals, walrus, raccoon,
weasels, civets, hyenas, skunks, and cats. Carnivores are late entries into the mammalian
family tree. Prior to their
appearance, representatives of herbivorous, insectivorous and omnivorous
mammals had existed for close to 100 million years.
But once these new specialists appeared, they quickly radiated out into
numerous successful life forms. All
have four large canine teeth. Special adaptations for these predators include the
carnassial teeth, located in the rear of the jaws that function like scissors
to tear flesh and shear bone.
Although
most of these members include berries, nuts, and fruits in their diet, these
are the flesh-eating mammals. Cats
are the ultimate carnivores, while others like bears, foxes, skunks and
raccoons are more omnivorous. Carnivores are far less abundant than rodents
and lagomorphs, on which the carnivores predate. While meat is a much more
concentrated source of energy than plant material, it is relatively hard to
acquire. Thus, carnivores have
evolved a large brain to handle
the complex smell, hearing, and/or sight senses necessary to help secure their food
source.
Contrary to public perception,
most carnivores do not have permanent
homes. Other than for natal
purposes or for severe winter protection, few carnivores have nests that they use regularly.
More often, a nesting site is used once, or for a brief period, while a
particular food source is exploited.
Most mammals routinely patrol their range, taking several weeks to complete a
circuit, checking out all the potential prey sites along the way.
Dogs and cats are specialized to walk up on their toes (digitigrade
locomotion), while other carnivores, like bear, raccoon, and skunk, walk on
the soles of their feet (plantigrade locomotion).
All male carnivores have a well-developed speculum (penis bone).
Many
are important in the fur trade, although human interest in wearing furs has
precipitously fallen over the past twenty years, with a resultant drop in
harvested pelts.
Carnivores
are first known from the early Paleocene Epoch (65 million years ago). It now
appears that the Carnivora evolved from the ancestral insectivores or from the
same basal stock that gave rise to the Primates and Chiroptera. More
information on the evolution of carnivores can be found at Velvet
Claw.
Worldwide,
there are 8 families, 97 genera and 246 species of carnivores, of which six
families and 20 species are represented in the eastern United States.
Carnivores are not native to Australia, New Guinea, New Zealand, and Antarctica.
Sixteen
species are found in the Appalachian region. They range from the least weasel
(one ounce) to the black bear (400+ pounds).
BACK
TO THE TOP OF CARNIVORES
Family
Canidae - Dogs, Wolves and Foxes
Canids
include all dogs, wolves, coyotes, foxes, dingoes and jackals. Canids all have elongated
muzzles, long legs and bushy tails. Their long nose provides them with
excellent olfactory senses necessary for scenting prey and "reading"
scent posts of other animals. The presence of molars behind the scissor-like
carnassial teeth allows the canids a more varied diet than the feline family
(which, in the absence of the molars, must rely solely on carnivory). Members
of the canid family have four toes on both front and rear feet.
Canids
are the most cursorial (adapted for running) of the carnivores. While
foxes can stalk their prey, most canids rely on chasing down their prey.
In
addition to their long legs, they have evolved a long muzzle with convoluted
spiral bones which enables the long distance runner to conserve moisture and
warm or cool the air before it reaches the lungs.
Such adaptations enabled the early canids to dominate the open
grasslands, where they reached their zenith 20 million years ago with some 42
different genera.
The
larger wolves are known to hunt in packs of up to 30 members, enabling them to
obtain prey much larger than themselves.
The smaller canids normally hunt in smaller groups or occasionally
in pairs (coyotes), or as solitary predators (foxes). They frequent
home ranges that may include actively defended territories, and have evolved
complex and varied social systems. Canids
are generally active year-round with females giving birth only once a year.
Males are generally larger than females in a given population. Young are born altricial, requiring considerable maternal care.
The
red wolf (Canis rufus) is presumably
no longer found in the wild. The last remaining red wolves were captured in
eastern Texas in the 1970’s. Red
wolves had been reintroduced in the Great Smokies National Park in 1991, but
for various reasons, were removed in 1998.
It has been successfully reintroduced, however, into the Alligator
River National Wildlife Refuge, NC, in 1987, and three other southern coastal
islands. (These three islands
serve as breeding areas, since they are too small to sustain a permanent
population.) As of 1997, there
were about 50 red wolves at Alligator River, 30 at other sites, and 160 in
captive-breeding facilities.
Since
the red wolf is no longer a member of the Appalachian region fauna, it will
not be included as a listed species. However,
information on the red wolf and the reintroduction efforts can be found at RED
WOLF.
Recent
DNA studies suggest that the red wolf is actually a hybrid between the gray
wolf and coyote and, thus, arguably
should not be recognized as a separate species. However,
that view has been questioned based on other interpretation of genetic data
that suggest the red wolf is a primitive animal that has been present in the
Southeast US since the mid-Pleistocene.
The
gray wolf (Canis lupus) has also
been extirpated from its former range in the eastern United States, and thus
will not be included. Limited
information on this species can be found at
GRAY WOLF.
The
earliest domesticated dogs (Canis familiaris) date back to Idaho and
Iraq, some 11,000 and 12,000 years ago, respectively. It is currently
believed that the origin of the domestic dog is derived from one of the small
south Eurasian subspecies of gray wolf (C. lupus) and subsequently spread
throughout the world in association with people. Today, there are
approximately 400 breeds of domestic dog, from the smallest chihuahua to
the Irish wolfhound. The Australian dingo (C. f. dingo), is itself
a feral subspecies of the domestic dog. In fact, it is possible that some
of these dingos were brought across the Bering Strait to North America some
3,000 - 4,000 years ago and persist today in the form of the Carolina
hunting dog.
There
are an estimated 50 million owned dogs in the US, and many more lack
owners. In 1975, there were an estimated 80,000 - 100,000 dogs in
Baltimore, MD, of which up to half were free-ranging, implicated in the spread
of several diseases, and benefiting rats by overturning garbage cans.
There are 1 to 3 million reported attacks annually in the US, with 18 people
killed by dogs in 1990 (8 by pit bulls).
This
family is known from fossils going back to the late Eocene Epoch in North
America and Europe, some 38 million years ago. More information on the
evolution of canids can be found at Velvet
Claw.
Within
the Canid family, there are 16 genera and 36 species worldwide (Nowak), with four
genera with nine species known from North America (Jones).
The canids are represented in this Appalachian Region by
the coyote, the red and the gray fox, and the feral domesticated dog (not
given a species account).
BACK
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COYOTE
(Canis latrans) (dog; a barker)
ARTICLES
Appalachian
Region Distribution:
Coyotes are known to exist in every county in PA, MD, VA, WV, and NC.
They were first found in the Smokies in 1982. See remarks for more detail.
The first confirmed coyotes in the Shenandoah National Park were photographed
in the winter of 2000/2001.
Continental Range: Although
originally a western species, the coyote has been introduced throughout the
eastern US and now is found in virtually all of North America. Until the early 1900’s, the range extended only as far east
as northern Wisconsin and central Texas.
Removal of the gray wolf in the east made room for the gradual move
into the east by the coyote. Three
subspecies recognized in eastern US,
with one in the Appalachian region.
Abundance: More common in the
open land of the coastal plain and piedmont; uncommon in mountainous areas,
although the largest concentrations in Virginia are in the mountainous
southwest corner of the state; being populated by an expansion of coyotes from
the west. General eastern population is increasing.
Population Density: Varied reports
from 0.065 (1/16 sq mi) to 1 per square mile. Nowak reports an average
from .3 to .6 per square mile, up to 3 per square mile.
Size and Molt: Head and body 32 to
37 inches, 30-40 pounds. Males are
slightly larger than females. (The eastern US population is about ten pounds
bigger than the western subspecies, purportedly due to interbreeding with
Canadian wolves. The largest
coyotes are found in the northeastern US, where the most interbreeding with
the larger gray wolf has occurred.) One molt between late spring and autumn.
(Unlike the typical two summer/winter coats associated with two molts, this is
a different method of molting, with the loss of the longer winter hair in
spring, and not replaced until the autumn regrowth.)
Mammae: Four pair. (Mammals of
Virginia says ten)
Habitat: Prefers open range land
and brushy, disturbed forest edges. Not common in mountainous areas.
Active Period: Chiefly crepuscular (with peak activity in the early evening), but is often out during the day,
especially during the summer. Active year-round.
Diet: Rabbits and rodents make up
most of their diet, but they can be quite omnivorous (opportunistic).
An Adirondack study of 1500 coyote scats found throughout the year
revealed mammals in 78 %, fruit 21 %, insects 10 %, birds 3 %, and amphibians,
reptiles and green grass. Snowshoe rabbits were the most common mammal at 40% (mainly
in winter). Carrion is a
significant part of their winter diet. Will cache food supplies. The ultimate
flexible hunter, the coyote will hunt singly, in pairs, or in groups of six to
eight, depending on the size of the available food supply. The larger the
prey, the larger the number of predators.
Wilson notes that, while the killing of large prey is seldom seen by
coyote packs, often packs will congregate around the carcasses of animals that
died of other causes. Since mated
pairs cannot deter intruders from taking large prey, it may be the protection
of the carrion that encourages the formation of packs. Coyotes have been
known to follow badgers, since badgers will often flush a ground squirrel out
of a separate burrow not noticed by the badger.
Home Range: 3-30 square
miles. Ranges vary by
geography, habitat,
season, and sex (and author). There is also large variations among
individuals of the same population. Home range is also influenced by social organization.
Typically, only pack members defend territories, while mated pairs and
individuals do not. One study showed
packs will normally have smaller home ranges as a group (5.5 square miles)
since their food base is dependant on defending ungulate carrion in winter,
than singles or pairs (11.5 square miles). Among individuals,
male ranges generally are larger than females. Rue reports 36 square
miles for males and 6 square miles for females. One Arkansas
study found males averaging 8.1 - 16.2 square miles, and females averaging 3 -
3.9 square miles. However, in a
Mississippi and Alabama study, females had a home range of 16 square miles and
males averaged 5 square miles. A
western Tennessee study found 12 square miles for males and 24 square miles
for females. Wilson notes ranges of up to 20 to 28 square miles,
with no consistent sex differences. A
male's territory is large and may overlap several females and other males, while ranges of
the female will normally not overlap other females. In times of scarce food resources, territories will be
temporarily abolished, although dominance is not.
Social Structure: Very
social (less than wolves), but also incredibly adaptable and behaviorally
variable as a species. Coyotes
may live singly, in pairs, or in packs. The available prey will in large part determine size of social unit
(solitary in areas of rodents; packs of 3 to 7 in areas with only large
ungulates). Thus, as opposed to the
western, open grassland populations, supporting large herbivores, it would
be reasonable to assume most coyotes in the Appalachians would tend to be in
pairs or singles. A
dominance hierarchy exists in the pack, with the older male and female forming
the alpha pair. The alpha pair
will be the only mated pair within the pack.
A pack will normally contain the mated alpha pair, single
(non-dispersing) individuals from previous season offspring, and the young of
the current season. Although some
of the pairs bond for life (especially in areas of low densities), coyotes normally don’t mate for life, but may
stay as a pair for several years. While the single pair is the basic unit,
solitary individuals and packs may all exist in the same geographic area and
often feed and den together. Both
parents and (often) siblings from an earlier year care for the young.
Dispersal normally occurs in the first autumn and early winter.
Social units may
change over the season as available prey changes.
Coyotes tend to be more social in winter when carrion is a more
significant food source. Others suggest coyote groups do not necessarily form for
taking down large prey, rather, cooperative group defense (protection of the
carrion from other packs) appears to be the major selective force favoring
increased sociality. (If pack
size was determined by prey capture need, the size of the pack should
stabilize at the point of maximum meat yield per capita.
However, packs are usually found to be larger than simple efficiency
should dictate – i.e., there are more pack members than necessary to make
the kill.) Thus, the
correlation between pack size and prey size may be a result of pack size,
rather than a cause of it. Clearly,
there are many factors involved with pack size.
For example, there is evidence that as food resources become limiting,
birth rates decline as the pack size increases.
Other factors affecting pack size include range quality.
An increase in pack size can be the result of delayed juvenile
dispersal. This may occur when a
habitat is saturated and prospects for establishing a new territory are
slight, requiring the dispersing youngster to travel a long, hazardous journey
away from its pack. Additionally,
as competing packs become more an issue, the dispersal of juvenile will also
be limited (due to fear of being killed!).
Both these two issues of habitat saturation and competition among packs
may explain larger packs than necessary (most efficient) in the wild.
Life Cycle: A late winter mating
(February or March – Wilson says early to mid winter) results in one litter
with an
average of six young per litter per year (the largest litter
recorded is 19), born in late April to early May. Unlike domestic
dogs that come into heat twice a year, coyotes are monestrous; breeding only
once a year, during the variable period of estrus, or heat (Nowak reports a
range for estrus from 4 - 15 days with 10 being the average; Rue
reports a 20-21 day heat period). Usually,
about 60 – 90% of adult females and 0 – 70% of female yearlings produce
litters (primarily dependent on food supply and social structure).
Gestation period of 63
days. Some coyotes mate for life, some for just a season, most for several
years (not too much unlike humans). The male (as well as last year's
siblings and/or other subdominant males) may provide the food to the female
during the first 3 to 4 weeks, while the kits are non-mobile. (With
domestic male dog-female coyote pairs, the domestic males' lack of feeding of
the female normally dooms most coydog litters. See remarks
below.) Parental care is often assisted by others of the pack during the first
season (including defending the group’s territory). Coyote pups have round iris, unlike the
vertical slits of the red and gray fox kits. The den is abandoned when the
whelps are weaned at five to seven weeks of age (Mammals of Virginia says pups
aren’t completely weaned until they are more than three months old.) The
family stays together until fall, when the juveniles normally disperse.
Males tend to disperse further from the birthing site than females (10-30
miles for females and 50+ miles for males). Occasionally, last years' siblings will over-winter with the parents,
helping to raise the young the next season.
Most young require two years to reach sexual maturity, however, a few reach
maturity in one year, depending on winter severity and food resources. (Wilson says 9 to 10 months is usual). Dispersing individuals may join other
packs for varying amounts of time or may remain as transients. Life span is about 8 - 14 years, while individuals less than
one year of age tend to have a mortality rate of 68%. The record was a
coyote in the Washington Zoo, living to 18 1/2 years.
Dens/Nest: Other than for breeding,
coyotes do not den up. They will sleep anywhere a concealed site can be found. For breeding,
coyotes make two or more burrows ten to thirty feet long into banks or hills
to a den measuring a foot wide and two feet high, and three feet below the
surface. Tunnels may be connected by numerous interconnecting
tunnels. Often,
abandoned woodchuck, skunk, or fox burrows are used. A mated pair will utilize the same
den year after year. Dens can be identified by prey remains and
flattened vegetation around the entrance. No nest material or lining
is used in the nest chamber.
Tracks: Tracks are 2 ¼ wide to 2 ¾
long and
oval; four toes and claws. Straddle is about 6", with stride being 14 to 16"
(24" when trotting), while a small dog is
more like 10 to 12". Coyotes tend to "perfect step" more than
dogs (rear foot on top of front step - dogs overlap more), with less foot
drag. Dogs also tend to wander more than coyotes, who, along with foxes, are
known to walk in straight lines. The distance between the tracks of a coyote is about
6", while
the fox is more like 3 - 4".
Scat: Coyote and fox scats are very
similar (lots of hair), with coyote being a little larger. Both have tapered ends, the coyote
being 2 to 5" long and ¾" – 1” diameter. (Scat of this diameter
is probably coyote.) Often found
on rocks or other prominent spots. Relatively, fox scat diameter is 5/8”,
bobcat is 6/8”, and coyote is 7/8”.
Remarks:
Coyotes are now believed to be found in every county of the five states in
this Appalachian study area. As many as 4,000 coyotes were harvested in Virginia in
2000, and over 6,000 in Pennsylvania in 2000.
Four SW Virginia counties still offer $50 bounties and each county has
a budget of $1500 - $2500 per year; so this comes up to about 160 coyotes.
However,
this is changing as counties realize the futility of bounties to control
livestock damage. Instead, Livestock coops, state and federal agencies
are forming joint programs to better address specific cases of livestock
damages. The VIRGINIA PROGRAM can be viewed here. A similar
program is on-going in West Virginia.
Similar
to a slightly built German shepherd, this carnivore has a busy tail tipped in black. Large
variations in pelage exists from nearly all black to nearly all white phases
(approximately 25% of the coyotes in Virginia are mostly black).
Coyotes
are the most vocal of all North American wild mammals.
The coyotes are known for a wide range of vocalizations. Howls are most
prevalent at night during the mating period. The eastern population doesn't
seem to bark as much as western populations, but their calls are becoming more
prevalent. When running, coyotes
distinguish themselves by holding their tail between their legs. All other
canids run with their tail either parallel (wolves) or curled over the back
(domestic dogs). A good
swimmer.
Coyotes
are adept at developing new foraging strategies. In what's known as a "hunting partnership", they are known to
travel with badgers on hunting voyages.
Often the keen smell of the coyote will locate a burrowing rodent. While the badger digs furiously at one opening, the coyote will station
itself at another opening, ready to catch an escaping prey. Nowak
comments that they both share in the proceeds, but I seriously doubt they
share the same critter. Coyotes also often work in pairs; one approaching conspicuously to
attract the attention of the prey, while the other stalks it from behind.
Coyotes
readily breed with domestic dogs and bear fertile offspring (coydogs), who
also can breed with either dogs or coyotes. While all members of the Canis
genus can (and do) interbreed (dogs, wolves, and coyotes), due to the size
difference, male wolves are known to breed with female coyotes or dogs, but
not typically the other way around. Before
the advent of Man, geographic isolating mechanisms kept the various species
from interbreeding. With coyotes
coming into heat only once a year in late winter, and dogs twice a year,
overlapping breeding periods are not common (male coyotes are only able to
breed when females are in estrus – males can only produce viable sperm for a
period of 3 to 4 months). With male dogs
capable of mating year-round, most coydogs are from male dogs and female
coyotes. Since male coyotes help in pup-rearing, while male dogs do
not, this lessens the likelihood of successful coydog raising.
Additionally, estrus in coydogs comes especially early, producing young
in January or February; a time unfavorable for survival. For
these reasons, the amount of domestic dog genes in coyote bloodline is
probably extremely low.
When
mating, the male mounts the female in the traditional manner, and then the
male steps over the female's back and the couple remain locked at 180° for a
period of up to 25 minutes.
Coyote
and fox pups look alike, thus adding to eastern populations of coyotes, when
received coyotes are released, mistaken by the original takers as fox pups.
Coyotes
are intolerant of foxes and bobcats, and will increase in population at their
expense.
In
1976-77, nearly 400,000 coyotes were taken in the lower 48 states.
The
name coyote comes from the Aztec word coyotl,
meaning barking dog. It
should be pronounced “ky-o-tee”, not “ky-ote”.
BACK
TO THE TOP OF CARNIVORES
RED FOX (Vulpes vulpes) (fox; fox)
ARTICLES
Appalachian
Region Distribution:
Throughout.
Continental Range:
Throughout Canada and US., with the exception of the Rockies.
It is, in fact, the most widely distributed carnivore in the world,
occurring in North America, Asia, Europe, and northern Africa (and now,
introduced to Australia). Two
subspecies recognized in the eastern US,
with only one in the Appalachian region.
Abundance: Common.
Population Density: 2 -3/square
mile.
Size and Molt: Head and body 22 to
25 inches, 8 - 12 pounds,
(averaging 9 1/2 pounds, with the largest male weighing 16 pounds 1 ounce,
shot at Conneaut Lake, PA).
One fall molt (with additional winter underfur).
Mammae: Four pair.
Habitat: Few animals occupy such a
diverse range of habitats as the red fox.
Deciduous successional woodlands with some open land are ideal habitat.
They select areas of greatest diversity and use edges heavily.
Dense forests are avoided, except occasionally in winter.
Active Period: In summer, mainly
nocturnal, but crepuscular to a degree (dawn and dusk).
In winter, more diurnal, to fit the diurnal nature of the voles; their
main winter food. Red fox will cover up to 5 miles a night moving on
their circuitous route around their home range.
Diet: Omnivorous, including
rabbits, mice, insects, berries, and birds.
Red foxes are solitary hunters, specializing on small mammals.
Like weasels, red foxes (and other canids) cache what they can’t eat
on the spot. Meadow mice and
field mice in the spring/summer, insects and fruits in the summer/fall, and
rodents (specifically meadow voles) and rabbits in the winter seem to be most
common. They will also eat carrion. Unlike
other canids, who chase down their prey after approaching it in the open, red
foxes stalk their prey, then put on a burst of speed, much like a felid.
Daily consumption is 1-2 pounds a day.
Home Range: About one square mile,
or 640 acres, with a range from 250 to 1500 acres. Can be from 25 to 100 acres in suburbia to
5,000 in farmland and 8,000 in the Arctic.
Home ranges have been observed to be twice as long as wide.
Ranges are normally larger in winter, determined by food resources. Red
foxes are apparently territorial, with little overlap of home ranges. A
home range is typically occupied by an adult male, one or two adult females,
and their young. Occasionally two females have litters in the same
den.
Social Structure: Red fox normally
mate for life, the male supplying all the food for the vixen (sometimes
assisted by last years' kits) and protecting the territory when she is nursing the kits.
However, solitary as a hunter, and quite territorial.
A pecking order is noted among males with overlapping ranges, with the
dominant male excluding other males during the breeding season.
Combatants will rise on their hind feet, putting their forefeet on the
shoulders of the opponent, with the first to back off being the loser.
This “dancing” is also seen in foreplay between a male and female,
often over a week or two prior to actual mating.
After mating, the male will leave until the female gives birth.
At this time, the male normally returns, supplying food for the vixen
and pups. Often, unbred females, such as
last years' female pups, will assist in bringing food to the
young. In areas with multiply
dens, males may mate with different females and not provide parental care.
Females are also known to mate with different males before settling down with
one male. The family (including the parents) will disperse by late
summer. Communal denning is known to occur in some areas.
Life Cycle: One
litter per year, averaging five per litter (the largest litter being
17 pups). In the Appalachian study area, breeding begins as early as late December, peaking in January and early February (later to the north). Males produce viable
sperm only between the middle of December through February. monestrous, with an estrus of 1 to 6 days
(Rue says 3 weeks). Gestation period of 51
days, with most birthing taking place in March.
For the first week, the female stays with the pups and is fed by the
male. Pups are weaned at eight weeks (now called kits) and leave the family
at six months (mid-September or early October).
Parents also separate for the winter at this time.
Males disperse before females and travel much farther from the birthing site than females.
Wilson reports a midwest study finding males dispersing 18 miles and
females 4.8 miles (another was 24 miles and 6 miles, respectively). Young are
sexually mature by their first winter. Where
density is low and mortality high, 80 – 90% of the yearling vixens give
birth. Where population turnover
is low, as many as 20% of all vixens fail to produce litters.
As is the case with
a number of mammals, the number of young per litter increases with age for
most of the adult life, then decreases. Even
among the pups, a dominance hierarchy is quickly established, with the largest
(male or female) getting the majority of food while the runts usually starve.
Life span is three to four years, with a potential span of 12 years.
The record is 16 years in captivity.
Dens/Nest: Two types of dens
are used. Multiple short
dens (5’ to 10’ length) are used for winter protection and defense within
the red foxes home range. Mammals of PA,
Mammals of VA, and Rue report that, unlike the gray fox, the red fox has no
regular winter den and
sleeps in the open beneath brush of downed timber.
More
extensive dens are used in early spring for raising the young. Nesting dens are three feet wide, usually have at least two entrances (9 to
12" in diameter), 3 to 9 feet below the surface, at the end of 20 to 40 foot burrows,
preferably on the side of a slope. One
den had 19 entrances. Red
foxes may make their own burrows and dens, but also utilize abandoned burrows
of woodchucks or their own former den, adding tunnels and chambers with each
new generation. If woodchucks still inhabit a burrow, fresh soil will be found
around the main opening, whereas, red fox will not deposit soil at the
entrance and will more likely have animal remains around the den.
NAS and Rue says dirt pulled out of the burrow is spread around the entrance in an
apron about 2 to 3 times larger than that of a woodchuck. Red fox and woodchucks are known to occupy the same burrow system.
Communal red fox dens have been observed (11% of all dens in one
Wisconsin study). Dens may be used for a number of years by a succession
of generations.
Tracks: Front tracks are 1 3/4 inches long by 2 inches wide, hind
track slightly smaller, with five toes on the forefeet (only four show) and four on the hind feet with non-retractable claws. Fox tracks are often straighter and perfect-stepped (see
Coyote above) than the more wandering dog. Foxes tend to walk in straight
lines, from cover to cover. Red
fox are known to frequent the same route, producing well-worn trails. Straddle is 3 to 4". Stride is at least a foot, while a
domestic cat is less than a foot. Red
fox are known to backtrack in its own footsteps for some distance, then leap
away to one side and make off in a new direction.
Scat: Fox and coyote scat are
similar with tapered ends. Fox scat is 2 to 4" long and ½" – 5/8”
in diameter (summer scat is often shorter and not tapered due to the insect
and berry diet). Feces often left standing on end. Scats less than 7/16" in diameter are probably fox.
Relatively, fox scat diameter is 5/8”, bobcat is 6/8”, and coyote
is 7/8”.
Remarks: Whether the red fox was
ever indigenous to North America is subject to much study and debate.
Churcher (1959) reported that the red fox may have been native north of
latitude 40, which runs roughly from northern California through Denver and
Philadelphia. Forsyth and Shedd
mentions fossil skeletons have been found that predate European settlement.
Eight pair of red foxes were reportedly introduced to Queen Annes
County, Maryland from Liverpool shortly after 1650, spreading rapidly,
reaching Virginia in 1679. Bartram
noted that it was first seen in Montgomery County, MD between 1798 and 1802.
Audubon and Bachman (1851) noted that the red fox was not known south
of Pennsylvania in historic records, but progressively was noted expanding
south through the colonial period. Current
consensus is that the red fox of the middle Atlantic states is a descendant of
the English fox with interbreeding from the northern native American red fox.
It
has been suggested that the range of more northern red foxes contracts
northward during warm periods (such as 5000 – 2000 BC) at the same time that
the more southern gray fox ranges more to the north. The same shift in range may have occurred during another warm
period of 1000 to 1300 AD. Gray
foxes apparently disappeared in New England, as did the red fox, until this
past century.
In
many respects, the red fox is more like a member of the feline family than the
canid family. For example, the
red fox is a solitary hunter that often hunts by stalking and short bursts of
speed rather than long chases. They
are also known to “play” with their prey before eating it, like a cat.
The red fox’s eyes have vertical pupils that can narrow to a slit and
a reflective membrane at the back of the eye causing light to pass over the
retina twice, enabling the fox cat-like excellent seeing abilities in both
extremes of light conditions. Red foxes also have partially retractable claws, aiding it in
stalking and pinning down its prey. Unlike
a dog that will vigorously shake its prey from side to side, the red fox will
simply bear down with its clenched teeth, much like a cat.
Red foxes have longer whiskers than dogs.
Finally, red foxes threat display towards other foxes is very much
cat-like, with its hair standing up, arching its back and turning broadside to
prance towards its protagonist.
The
hearing of red fox differs from most mammals in that it is tuned to lower
frequencies that enable it to pick up the underground digging and gnawing of
it's prey species.
The
white-tipped tail differentiates this from the gray fox with a black-tipped
tail. Pelage color is highly
variable, although most are a reddish yellow or tawny red. From 1900 to 1920
in North America, catching and raising wild foxes developed into a major
industry with farms employing up to 400 workers and paying up to $1,000 for a
choice animal. Three color phases
are recognized. “Cross” is a
mixed gray and yellow, with a dark line down the back and a second crossing
band across the shoulders. “Silver”
is a melanistic coat frosted with white.
“Black” is the melanistic coat.
Such color phases may occur in the same litter with normal red coats. The "silver fox" color phase of the northern range
is valued by fur dealers and raised on farms. Winter colors are more vivid
than the more subdued summer pelage. Winter
fur length is longer than summer.
Red
foxes are used in hunts over the gray due to their increased speed, endurance
and stamina (grays tend to escape to treetops too quickly). Red fox are good
swimmers and can run up to 32 mph. During
the mating period of mid-winter, the urine gets a musky, skunky odor which can
be noticed at some distance by hikers.
As
coyote populations increase, there will be a corresponding decline in the red
fox population. However, foxes,
who tolerate human habitation better than coyotes, will tend to move in to
more suburban areas.
The
red fox is a principal vector and victim of rabies in the Northern Hemisphere.
Recent experiments dropping medicated meatballs from airplanes into
affected areas has proven to effectively control rabies.
In
the 1976-77 season, 421,705 red foxes were trapped in the US and Canada, and
rose to over 500,000 in the early 80's.
BACK
TO THE TOP OF CARNIVORES
COMMON GRAY FOX
(Urocyon cinereoargenteus) (tailed,
dog; gray, silver)
Appalachian
Region Distribution:
Throughout.
Continental Range: Most of
the continental US with the exception of the Great Plains and the Pacific NW.
Four subspecies recognized in eastern US, with only one found in this
Appalachian region. (U. cinereoargenteus cinereoargenteus).
Abundance: Common.
Population Density: 3-10/square
mile. (W/H and Wilson says 1/2 -
1/square mile, Nowak reports a range from 0.6 to 16 per square mile.)
Size and Molt: Head and body 24 inches,
9-11 pounds,
with the largest recorded at 19 pounds. Males weigh
1 to 2 pounds more than females. One
molt.
Mammae: Six functional mammae.
Habitat: Prefers wooded
forests (more so than red foxes), although very adaptable to different
environments, including rural to semi-developed suburban areas. Prefers
habitat near water.
Active Period: Crepuscular to
nocturnal. More nocturnal
than the red fox.
Diet: The most omnivorous of the
canids. Percentage of plant
versus animal seems to be a function of habitat rather than preference.
Rabbits and small rodents often make up a majority of their diet,
especially in winter. In late
summer and fall, persimmons, grapes, acorns, apples, grasses and corn make up
a third of its diet. Grasshoppers and crickets may be particularly important
in the fall. Eats more berries
and birds than the red fox. Other studies show the gray fox having more
vegetable in their diet than red fox. Caches
excess food.
Home Range: 0.3 to 2 square
miles for a family (210 - 1280 acres).
Similar figures reported for individuals. Nowak reports about 1/2 to 3 square
miles. Chapman and Feldhamer report 0.3 to 0.73 square miles ( 187 acres
to 462 acres). Unmated foxes
may overlap family range. Chapman and Feldhamer reports two studies that
both indicate home ranges overlap. Home range is larger in winter.
Social Structure: Are normally monogamous,
paired for life, although occasionally polygamous.
The family stays together for the season, with both participating in
gathering food for the young, although NAS says the male will not den with the
family.
Life Cycle: One litter a year with an average of four (1-7) born from early April to
May. Most breeding
takes place from late February to mid-March (Nowak says up to late May in New York). Roughly, it can be stated
that red foxes give birth a month earlier than gray foxes (March versus
April). Females are monestrous,
with a gestation period of 55
days (reports of 53 to 63 days). After
the first four to six weeks, the male is allowed to assist in child rearing by
providing food (Rue says male provides food to the female during this period). Young are weaned in eight to ten weeks, and on their own by
fall. The family stays together
for the summer, then disperses in the fall or late winter. Some of the pups will breed in the
coming spring, others not until their second year.
Life span of eight to ten years. (W/H
says most die before the age of two, although captives have lived 14-15
years.)
Dens/Nest: Dens are normally used
only for
winter protection (unlike the red fox) and for the spring reproductive season.
Den sites are reused year after year by a mated pair. Little vegetation
or no nesting
materials are used. Often uses
more than one summer den. Dens
are in dense brush near water (not open fields, like red fox). Gray foxes are
less particular about their sites than red foxes.
Such sites can include high up in hollow trees, hollow logs, stumps,
rock outcrops, slab, scrap and brush piles. Will use ground hog holes and, as
a last resort, will make it’s own burrows. Have even been found in the same
den as woodchucks. Unlike
the red fox, gray fox dens usually only have one entrance, and never more than
two.
Tracks: Front length and width is 1
5/8 x 1 3/8"; rear length and width is 1 1/2 x 1 1/4", with a
straddle of 3 3/4" and a slow stride of 8 - 12". Four toes
show in the tracks, since the fifth toe (the dewclaw) on the front foot does
not register. Gray foxes have larger toe pads on smaller feet than red
foxes.
Scat: Generally 2 ½" by
½", with tapered ends, not twisted.
Usually not segmented.
Remarks:
There are only two species in this genus, both found in North
America.
The only canine that can climb trees. It will take to the trees when pursued.
More secretive and shy than the red fox.
The gray fox is unique among North American foxes in that it has stiff pelage
instead of soft fur. Body coat is a grizzly, or "salt and pepper" gray with a
long, bushy tail having a distinct black stripe on it’s dorsal side and
black tail tip. A black patch can be found on the top of the muzzle and on
the chin. The gray fox has reddish-tawny sides and flanks, but not the top
dorsal side, like the red fox. Gray
foxes are not used for hunting since they will hole up or climb a tree in
little time. Foxes may contract
either the aggressive "street" rabies or the non-aggressive
"dumb" rabies (which is suspected to be the type affecting bats).
Coyotes
seem to outcompete gray foxes in overlapping ranges. Between the red and gray, the gray fox seems to be the aggressor and tends to
force the red fox out of its territory.
Gray
foxes make better pets when raised from pups than red foxes.
It is said that they are infrequently hit by cars due to their speed, agility,
but I’ve seen at least ten road kills along Rt 50 between Annapolis and D.C.
in the 1990's. Specifically, all within a few mile section centered
around the Route 424 Davidsonville exit. It is also noted that gray fox don’t
tend to shy away from hunters with spotlights. Since that time, the number of road kills observed has
basically stopped. Perhaps the population has moved.
In
the 1976-77 season, 225,277 gray foxes were taken in the US.
27,000
gray foxes were "harvested" in PA in 1983, with a record 66,975
trapped or hunted in 1984. The
record low was 23,102 in 1988. 32,922
were harvested in 1998. The
northcentral portion typically yields the largest numbers (10,524 in 1998).
BACK
TO THE TOP OF CARNIVORES
Family
Ursidae - Bear
This
family represents the eight species of bear; three of which are found in
North America. The three species are the polar bear (Ursa maritimus),
the brown, or grizzly, bear (Ursa horribilis), and the American black
bear (Ursa americanus). The
ursid family includes the largest terrestrial carnivore, the polar bear, which can weigh over 1700 pounds (The
brown bear can weigh up
to 1600 pounds). Ursids are an offshoot from the canid evolutionary line,
dating back 15 million years to the middle Miocene Epoch of Europe.
Grizzly bear and polar bear are relatively recently evolved
creatures, with records going back 500,000 years for grizzlies and only
200,000 years for the polar bear. In
fact, the polar bear, an offshoot of the grizzly (evolved to capitalize on a
diet strictly limited to seal carnivory), can still mate with grizzlies and
bear fertile offspring.
Ursids
are robust animals with small eyes, small, round ears, and “cute” little
tails. Unlike
their agile, fleet canid and felid relatives, these carnivores are large and
ponderous, flat-footed, with teeth adapted for crunching and grinding, rather
than piercing and ripping. Skulls of most ursids are massive with elongate canines, weakly
developed carnassials and broad, flat molars. The molars allow them to be
more opportunistic hunters; practically omnivores, feeding on berries,
insects, fruits and carrion. The bears are plantigrade, like raccoons (and
us humans). Although bears live in cold regions and sleep for extended
winter periods, they are not true hibernators, with breathing and
respiration only slightly reduced and able to awake in short notice.
Although bears mate in spring, delayed implantation allows for a mid-winter
birth.
The
large size of bear is an adaptation to winter, when the bear den up for
several months, living off their stored fat.
Their low metabolism allows the brown fat to enable a long period of
winter dormancy. A cost of this
large size is the extremely large home range, up to several hundred square
miles in more northern regions. As
a result, bears are territorial, seldom congregating, except at particularly
rich feeding grounds, such as salmon runs and garbage dumps.
Another benefit of their large size is that they have no natural
enemies, other than man. All three of our North American species
breed in the spring, but have a 'delayed implantation', with the embryo in
an arrested state of growth for five months prior to active gestation,
enabling a mid-winter birthing.
There
are 8 species in 3 genera of bears in the world (Nowak), with 3 species represented
by the Ursus genus in North
America. Only one species, the
black bear, is found in the Appalachian region. Black
bear are derived from Etruscan bear stock of
Asia, making its way into North America via the Aleutian land bridge by the
middle of the Pleistocene (500,000 to one million years ago). Two later species; the brown
bear (grizzly) and Polar bear, are found in North America. Limited
information on grizzly bears can be found at GRIZZLIES.
BLACK
BEAR
(Ursus americanus) (bear; from
America)
ARTICLES URSID
EVOLUTION
For
a Master's thesis on "Seasonal Movements , Habitat Selection and Food
Habits of Black Bears in Shenandoah National Park" by Nathan Garner
(1986), go to GARNER.
For
a Master's thesis on "Population Dynamics and Denning Ecology of Black
Bears in Shenandoah National Park" by Daniel Carney (1985), go to CARNEY.
For
a Master’s thesis on “Response of Black Bears to Gypsy Moth Infestation
in Shenandoah National Park, Virginia” by John W. Kasbohm (1994), go to KASBOHM.
For
two Master’s theses on Maryland bears, go to MARYLAND
BEARS
.
For
a review of Pennsylvania’s bear population, go to PENNSYLVANIA
BEARS
.
Appalachian
Region Distribution:
Throughout.
Continental Range: Throughout Canada, mountains and the lower
Mississippi River- valley of the US. Only
one subspecies found in this Appalachian region; Ursus americanus americanus.
;
the two other subspecies described
being
found along the Gulf coast.
Abundance: Common in remote
areas of suitable habitat. There
are approximately 400 to 600 black bear in the Great Smoky Mountains
National Park and 500 to 700 in the Shenandoah National Park, depending on
food resources.
Population Density: The above
mentioned 1985 study (Carney) in Shenandoah National Park, found bear
density to be 2.6 bear per square mile in the Central District.
Only two other areas (National Forests) in the continental US are
known to have higher densities; 2.8 to 3.7 bear per square mile in
Washington, and 7.8 bear per square mile in Alaska.
The Smokies have reported a density of 0.21 to 1.47 bear per square
mile. Nowak reports densities
ranging from 0.115 (1/8.7 sq mi) to 1 per square mile. Lynn Rogers'
intensive studies of northeastern Minnesota bears from 1969-1985 found home
ranges from 1/1.6 to 2.5 square miles.
Size and Molt: Black bear are
sexually dimorphic, with males much larger than females.
Head and body 4 ½
to 5 ½
feet in length, and height at shoulders 2 to
3 feet;
In the North American population, males
average
between 132
- 308 pounds, with females averaging between
88 - 154 pounds,
with individual males reaching over 600 pounds.
A study of black bears in the Smokies found an average for males
and females to be 250 and 104 pounds, respectively, with the largest male
weighing in at 510 pounds. Due
to the ideal environment provided by Pennsylvania’s woods, male bears in
PA average 500 pounds, with the largest weighing in between 650 and 700
pounds; and females ranging between 150 and 300, maxing out at 454 pounds.
Virginia’s population averages between 200 and 400, although one
killed in the Dismal Swamp, VA, weighed about 693 pounds (Richards, 1953).
Wilson reports
maximum weights for wild males and females to be 902 and 520 respectively
and average weights of 264 and 176. Black
bear generally reach full size at four years of age (Wilson says 10 – 12
years of age). Pennsylvania studies
show three year old males will average 223 pounds, four year olds, 280; five
year olds, 312; and six year olds will average 400 pounds (females will be
159, 179,195, and 205 respectively). One molt.
Mammae: Three pairs (with a
space between the lowest pair, allowing for a body fold.)
Habitat: All types of heavily
wooded forests and swamps. In the Appalachians, oak-hickory and mixed
mesophytic forests are most common. Understory plants of
blueberries, raspberries and blackberries are dominant. In addition,
cover provided by mountain laurel and rhododendron is preferred.
Active Period: Primarily
crepuscular in spring, diurnal in summer, and nocturnal in fall. Being
primarily vegetarians, when winter comes, they enter shallow torpor (bear do
not hibernate) for periods throughout the winter (the more southern range
requires shorter periods of time), but are easily aroused. Length of sleep
also correlated with fall buildup of body fat, which can be up to four
inches thick (more fat, more sleep). There is a
transition period into and out of denning, which may last up to a month.
In the Shenandoah National Park, most bears enter their dens around
December 1, and emerge in mid-April, although about 10% may remain active
all winter. In the Dismal
Swamp, up to 33% have been observed to forage all winter long.
In the Smokies, the average den entrance is between the last week in
December and the first week in January.
Den emergence averages between the last week in March and the first
week in April. In the Shenandoah study, pregnant sows enter the dens first,
followed by sows with yearlings, and males last. In the Smokies study, females entered first, followed by
males and then subadults of both sexes.
Emergence was in the reverse order in both studies. In Washington, the average period of dormancy is 126 days, while three
Louisiana bear slept for 74-124 days. See remarks for more
information.
Diet: Truly omnivorous,
vegetation makes up a goodly portion of their diet.
The carnassial teeth are not highly developed and do not have a
shearing function. After
emergence in spring, a relative period of food scarcity results in weight
loss. Typically, in spring,
grasses and forbs dominate with fruits and mast consumed in summer and fall.
Fruits (blueberries, blackberries, shadberries) and honey are
favorites. In a study over
three years in the Shenandoah National Park (1988-1991, taken from Kasbohm,
1994), Jack-in-the-pulpit made up over a third of the spring diet, cherries
and squawroot made up over 40% in summer, and grapes made up over a third of
the late fall diet. (This study was conducted during the period of maximum
gypsy moth damage; thus, the absence of the normal fall acorn mast).
A five year study in Virginia (1957) revealed that 62 % of the fall
and winter diet was composed of acorns.
Other foods include carrion, bird eggs, frogs, fish, insects
(especially ants), and honey. In
the fall, bears feed heavily and become extremely fat, thus well equipped
for winter. They may increase
their weight by up to 100% (one bear went from 110 to 220 lbs).
Average loss of mass in one study was 260 grams per day; over the
winter, that amounted to a drop of 23.1% from peak weight.
A study by Michael Pelton of the black bears in the Smokies found
that 81% of the volume of foods eaten was of plants, and 11% of the volume
of the total diet was animal foods. Artificial
foods and debris composed the remaining 6 and 2% respectively. Like raccoons, bear like sweets and eat honey.
While raccoons will only raid wild bee nests, black bear will invade
commercial beehives. Thick fur protects against stings. The bear
will also eat the bees. Bear will also eat fermented apples
and get drunk. Rue tells the story of two bear so intoxicated, they
could not walk. In fact, the Massachusetts State Game Commission temporarily
closed the bear season for five days one year to give the bears a chance to
sober up. Three game wardens were detailed to baby-sit with the bears
around the clock so that they would not be killed while in a stupor.
Once the bear staggered off, the bear season resumed.
Home Range: Home ranges varies with many factors, especially seasonal
food resources. The home range of males is typically three to eight times
larger than that of females. Studies
have found the following results for males and females: Smokies, 16 and 6
square miles; Pisgah National Forest, 24 and 7 square miles; northeast PA,
80 and 16 square miles, and Shenandoah National Park, 46 and 8.8 square
miles (see Garners study noted above).
Wilson reports a male range averaging 31 square miles and typically
encompassing 7 to 15 female territories.
Rue reports 30-40 square miles for males and 10 square miles for
females. Other studies report male bears have a home range of 10-15 miles with
a male’s range covering several female’s ranges (3-5 miles).
Lynn Rogers' Minnesota studies found mature males with overlapping home
ranges that averaged 30 square miles, while female home ranges averaged 3.84
square miles. Home ranges often overlap extensively, with bear often using the same
areas for the same activities, particularly foraging.
As a result, bears often compete within their home range.
Wilson notes that, if food is abundant enough to warrant it, females
with their independent offspring will defend territories, averaging four
square miles. Black bear exhibit excellent homing
instincts. See remarks below.
Social Structure: Solitary males.
Females and young stay together over the cub’s first winter, and
are forced away the following spring (to allow for the biennial mating).
There are some records of young overwintering a second winter with the
mother, like grizzly bear. Congregation at feeding sites is also observed.
Life Cycle: Females breed every
other year, except when the young are lost; in which case the sow can mate
and give birth in consecutive years. Unlike most mammals, who come into estrus for only a brief time,
female
black bears have a seasonally constant estrus; females remain in estrus
until bred or until the ovarian follicles begin to degenerate (On the other
hand, Nowak says females apparently are in estrus only 1-3 days).
Black bear are induced ovulators; ovulation occurs only as a result
of coital stimulation. After a summer mating (with the male and female together over a two week
period in late June or early July) and fertilization, the embryo
undergoes an arrested state of development for five or six months.
(Known as delayed implantation, this enables the bear in the fall to
concentrate its energy on fattening up on the available mast crop, instead
of expending its energy on mating. Interestingly,
if the mast crop fails and the sow fails to put on adequate brown fat before
entering the winter dormancy, the embryo will abort.
Thus, the delayed implantation prevents the sow from investing in a
pregnancy before her food reserves are established.)
The actual gestation period of 6 to 8 weeks begins in November or
December. Birthing takes place
in late January or early February (for a total pregnancy of about 220 days) with the cubs weighing only 6 to 10 ounces
and about 8 inches long; helpless, hairless, and eyes closed.
A sow's first litter is normally one cub, with two in subsequent
years. Occasional litters of
three, four, five, and even six are known to occur in ideal habitats.
In PA, where the habitat is ideal, twenty years of research have
found that sows give birth to five as often as only one (approximately 3% of
the births). After two months
nursing in the den, the cubs, now weighing roughly 5 pounds, emerge in April
with the mother. Cubs are
weaned by August to September, at seven months, now weighing about 50
pounds. After overwintering with
their mother, they will be forced
out by the mother early the second spring, in order to enable the mother to
mate again. The yearling females often find territory on the margins of their
mother’s home range, while the males travel well beyond to establish their
own territory (average of 36 miles for Lynn Rogers' males). The
father takes no part in child raising. Females normally start bearing at age
three to five; males, often a year later (Wilson says 2-9 for females and 3-4
for males). Life span for adults can be expected to be 15 years in the wild. With
some bear being aged in PA and New York in their 30's, the oldest
wild bear recorded is 41 years, 9 months.
The average age in a healthy black bear population ranges from 3 to 5 years
for males and 5 to 8 years for females. More than 90% of adult bear deaths come from gunshots, trapping,
motor vehicle accidents, or other human involvement.
Dens/Nest: Black bear have no
permanent summer homes, sleeping in trees or on the ground.
In the winter, they will make dens in hollow trees (even well above
the ground in snags), under stumps, in bank excavations, or even on surface
leaf nests. Males
normally make dens under rocks or tree falls while females tend to prefer
hollow tree snags for their winter's dormant period (a function of their
smaller size). (See Carney's
master thesis link at the top of this entry.)
One Michigan study (Erickson-1964) found nearly half were in cavities
under stumps and logs, 21% were in holes excavated in banks, and 11% were
under brush piles. A Smokies
study found seven of ten den sites in large trees (3’+) 20 to 60 feet
above the ground where the tree trunk, or a branch, had been broken causing
a large cavity opening to occur. In this
Appalachian region, a small percentage of bear will remain active all
winter.
Tracks: Five toes per foot. Hind
tracks are 6 to 7" long and 3 to 4" wide with a large heel pad.
Looks very human-like. Front tracks are 4" long and wide. Both have
five distinct toes and claws, with the largest toe being outermost.
Stride is about 1'. Tree-marking
(of “mark trees”) peaks during the midsummer breeding period.
These “bear trees” are often rubbed and scented by males.
Overturned rocks, broken branches, rotten logs broken open, matted paths
through berry patches, and scats on trails are all signs of bear habitat.
Scat: Scat varies by diet. Summer
berries form a loose mess, while fall mast produces little scat, which
quickly deteriorates. Otherwise, scat is in 2 to 3" segments that is 1
¼ to 1 ½" in diameter. Form is cylindrical with flat-ended segments.
Fecal plugs can be found in early spring, consisting of hair, wood
chips, twigs, leaf fragments, and small roots.
Remarks:
The
largest carnivore in the Appalachians, this dark bear often has white spots
on the throat and chest. Color
variations found in the western US are not found in the eastern US.
Unlike grizzlies, black bear are good climbers. Can run for short
periods up to 30 mph.
In
1997, as the result of a poor mast crop, a migration of black bears from the
Smokies to better feeding grounds resulted in 250 bears being shot in one
week in Tennessee.
Bears
are said not to truly hibernate, because, although their bodily processes
are slowed, they are not suppressed to the extent found in the deep
hibernators. Their metabolism drops by half; body temperature decreases from
a summertime 99-101 to 88-95, heart rate dropping from 40 to 50 beats per
minute to 8 to 19 per minute, breathing is only two to four times per
minute, and their digestive system tightens into a knot, with the limited
waste products reprocessed into the bloodstream in the form of proteins.
Newborn
cubs are 1/250th the weight of the mother, compared to 1/20th
for humans. The short gestation
and small birth weight are adaptations for reproducing during winter
dormancy. The energy base for
the sleeping sow switches from glucose to fatty acids, which are difficult
for fetuses to metabolize in utero. The
early birth enables the cubs to feed on the mother’s milk, essentially an
external pregnancy. The sow’s
milk is extremely rich, being 24% fat, compared to 4 ½ % of cows and
humans.
A
typical mammalian hibernator reduces its body temperature, heart rate, and
metabolism until body temperature is within one degree of the ambient
temperature. In addition, true
hibernators regularly awaken every few days to eat, drink, defecate, and
urinate. The black bear remains
dormant during the entire denning period (with a brief wakening interlude
during the birthing process).
The ability of bears to recycle urea and to desist urinating, defecating,
eating, or drinking during the entire denning period is unique.
(Nowak reports bears do emerge from their dens on occasion during the
winter, with those in southern latitudes more likely to interrupt the winter
dormancy by emerging outside during warm weather.)
Finally,
true hibernators can be handled and even removed from the den without
awakening, whereas, black bears can be easily aroused (ask any biologist who
is radio tracking bears into their winter denning sites).
Various
terms - dormancy, ecological hibernation, and carnivoran lethargy, for
example - have been used to indicate the black bear's various modifications
to hibernation.
It
has been said that, while bears may not be true hibernators, they are
digestive hibernators. In the fall,
about a week prior to den entry, the bear stops eating, thoroughly emptying
out their stomachs, intestines and bladders. The bear then eats
several fistfuls of grasses, leaves and pine needles, which passes through
the body and forms a fecal plug, up to a foot long
in the rectum, preventing the sleeping sow from endangering the health of
her newborn cubs.
ON
THE OTHER HAND..., evidence of black bear physiological behavior,
specifically, the electrocardiogram of bears and their metabolic and
excretory mechanisms, indicates that the “hibernator” designation
applies to bears. The winter
weight loss of bears is comparable to smaller hibernators (20-27% versus
25-30%), and the relatively high body temperature indicates that the
adaptation of bears is equivalent or even superior to those of other
hibernators. These adaptations
enable black bears to remain somewhat alert and care for the young in the
winter den. This ability to
react to disturbances is important to an animal as large as a black bear,
since complete concealment in a den is not usually possible.
The
timing of fall denning is ultimately a function of the food supply.
If a good mast crop exists, bears will remain out until the food
source is gone. Conversely, a
bad mast year will result in an early denning date.
It has been stated that a bear will enter its winter den when the
energy expended seeking out the food resources exceeds the energy gained by
the food resources. Black bear in northern habitats exhibit the most prolonged dormancy
(up to seven months), while those in the southern limits (Florida) will den
for about two months (due to lack of food, not cold).
Wilson says that only pregnant sows will “hibernate” in the
southern states, where food is available year-round.
As one progresses southward, black bears appear to be less lethargic
and can be easily aroused from their dens.
Bears
relocated from their home territory have returned up to 143 miles distant.
One relocated bear was shot two years later, one county away from its
original capture site, 240 miles from its release site.
Mammals of Virginia has the following account:
Probably
the most famous wandering bear in Virginia was a young female who was
eventually named Rambling Rose. Rose
had become a habitual and unwanted guest at picnics in the Shenandoah
National Park, and it was decided that for her own good, she should be
relocated. Rose was moved from
her home territory in Augusta County to Sounding Knob in Highland County, a
straight-line distance of approximately 58 miles.
Six days later she was back in the park.
She was trapped again and taken to Mountain Lake in Giles County,
approximately 125 miles from her home territory.
Rose returned again to the park and was caught 11 days later.
She had crossed several interstate highways and other major highways
and much open farmland on her journey.
Finally, Rose was taken to the Dismal Swamp.
She left immediately, went to North Carolina, and headed up the
Roanoke River drainage on the way back to the mountains.
Unfortunately, she was struck by a car and killed.
It is estimated that Rambling Rose traveled at least 773 miles during
her summer journeys (Anonymous, 1979)
Shedd
relates two stories of bear intelligence reported by Gary Alt, well-known
Pennsylvania biologist. The
first is finding a bear that after being caught only
once in the traditional culvert trap, entered the trap and kept the trap
door from closing by holding it up with its rear foot while retrieving the
bait. The second story was
finding a bear who, in order to elude its trackers, would stop in its
tracks, rise on its two hind feet and twist around, jumping perfectly in its
previous steps and retrace its steps for a number of feet before leaping off
in a perpendicular direction. Alt
tracked the same bear doing this twenty six times in two days, repeating the
same evasive technique every time, retracing its footsteps from fifty feet
to two hundred yards before leaping sideways off the trail.
Bear
are known to get drunk on fermented fruit. See diet
above.
The
helmets of Great Britain's Buckingham Palace guards are made of the black
bear's fur.
In
a Smoky Mountain National Park study, of 624 documented cases of aggression
toward visitors, only 37 (5.9%) incidents ended in contact.
An
average of 45 to 80 black bears are poached from the Smokies every
year. Most are killed for their claws, teeth, or gall bladders. In August of 1988, an undercover
operation, called Operation Smoky, resulted in the recovery of 266 bear gall
bladders, 385 claws, 77 feet, 4 heads, 9 hides and one live cub.
Nowak
discusses the trade of bear parts in Asia and reports that by far, the gall
bladder is the most valued part. He reports its value lies in
its use as a medicine to treat diseases of the liver, heart, and digestive
system as well as relieving pain, improving vision, and cleaning toxins from
the blood. In fact, a substance is produced in the bile that has been
shown to be effective in treating some liver diseases. In China, more
than 10,000 Asian black bear are maintained in captivity for purposes of
bile production. The animals are kept in small cage and
"milked" of their bile by a tube surgically implanted in the
gallbladder. Although this activity has been extolled as a
conservation mechanism, wild bears still are being killed and sold regularly
in China and their gallbladders are considered superior to those of
captives. In fact, a recent survey found that traditional doctors in
South Korea will pay $37.50 per gram for bear bile, and more than $1,000 for
a gallbladder from a wild bear. For this reason, the Asiatic black
bear has been identified as vulnerable by the IUCN and is on Appendix 1 of
the CITES.
With
a total population of more than 600,000 (Shedd reports 750,000), it has been
reported that probably 25,000 to 30,000 black bears are harvested each year
in North America.
A 1995 report indicated the presence of about 200,000 black bears in
the contiguous US, 150,000 for Alaska, and 330,000 for Canada.
Current
figures for this five-state Appalachian region include over 10,000 in West
Virginia (it wasn't until 1969 that
bounties on black bear in Pocahontas County were discontinued), while North
Carolina estimates that a population of 3,500 bear exist in their mountains
and 6,000 in the coastal areas in 2001. Pennsylvania estimates about
8,000 bear, Virginia maintains a population of 4,000, while Maryland's
population is around 200.
The
subspecies U. a. floridanus, of Florida, has an estimated population
of 500 - 1,000. Another subspecies, U. a. luteolus, with only a
few individuals left along the Misssissippi and lower Atchafalay rivers, has
been augmented by northern U. a. americanus, jeopardizing the genetic
viability of the native population.
BACK
TO THE TOP OF CARNIVORES
Family
Procyonidae – Raccoons
Members of this family include raccoons,
ringtails, coatis, kinkajous, olingos, and lesser pandas.
With the exception of the kinkajou, all these animals have alternating light
and dark rings on their tails. Differing from dogs, these mammals are plantigrades, walking on the
soles of their feet (like bear). Like
dogs, they have non-retractible claws, with five toes on both front and rear
feet. Procyonids are normally omnivorous, foraging both as predators and
scavengers. All are partially
arboreal and almost all found in North, Central, and South America. The lesser
panda is the only Asian member of this family.
(The giant panda is now included in the Ursidae family.)
Among the
carnivores, the Procyonids have most likely diverged from the Canidae, with
its earliest known fossils dating to the late Oligocene Epoch of North
America, some 28 million years ago. Information on the evolution
of procyonids can be found in the Velvet
Claw.
19 species among
7 genera exist worldwide (Nowak), with 3 species in 3 genera in North America
(Jones). Besides the Procyon
genus, which includes our common raccoon, two other genera in the Procyonidae family are known in North America, both in the SW US
(coati and ringtail). All
three are known for their long, alternately striped tails.
The
raccoon is the only procyonid in the Appalachian region.
It has been traced back to the Pleistocene.
COMMON
RACCOON
(Procyon lotor) (before the dog;
washer)
Appalachian
Region Distribution:
Throughout.
Continental Range: Every state in the US, southern Canada, Mexico
and Central America. Twelve
subspecies found in eastern US (three being found only on islands of the
Florida keys), with only
one subspecies in the
Appalachian
region.
Abundance: Common. Densest
populations are in the coastal plains.
Population Density: Highly
variable, from 2 to 5 or more/ square mile, with the low end being most common
in the Appalachian study area. The highest density reached 1,036 per square mile in a Missouri
marsh. Densities are greatest in
wet habitats, with 129 per square mile commonly found.
Population densities in hardwood stands and farmland reach up to 52 per
square mile, and suburban residential areas can maintain up to 178 raccoons
per square mile.
Size and Molt: Head and body 16 to
26 inches; weights average from 8
- 20 pounds (with records of
56 and 62 pounds). Males are
slightly larger than females (10 – 15%). Individuals from Wisconsin and the Upper Peninsula of
Michigan (and the north in general) are the largest and darkest of the eastern raccoon. Those from Florida are smaller, and commonly have longer rear
legs and tail, standing much taller when on all fours. One molt, with
the loss of old hair complete by early summer and new fur growing in
throughout the summer.
Mammae: Three pair.
Habitat: This adaptable creature
can make it’s home practically anywhere. Prefers moist and swamp areas,
stream and lake habitats. Not as
common in upland dry woodlands, especially where pines are mixed with
hardwoods.
Active Period: Fairly nocturnal,
except when hungry. Spends the day sleeping in trees. They do not hibernate,
but will stay in a den for several weeks of severe cold, living on its brown fat
layer (up to four months north of the Appalachian study area, only a few days
at a time south of the study area). Snow
initiates the onstart of dormancy, although later in the winter, raccoons will
emerge when several days of temperatures above freezing occurs, even with
substantial snow coverage. Rue reports
that at temperatures between 26 and 28 degrees, raccoons will den up.
Diet: Like the bear, the raccoon is
a true omnivore and opportunist. Also, like bear, the raccoon has lost its
specialized carnassial shearing teeth, and has developed crushing teeth to
accommodate their omnivory. Fleshy
fruits (soft mast), acorns (hard mast) and corn are important items.
In most habitats, plants are generally more important than animals in
the raccoon’s diet (except often spring, when crayfish make up the majority
of food). In spring and summer, feeds on insects, earthworms, snails, spiders,
birds and bird/reptile eggs, and small rodents. Carrion, crayfish, frogs, fish
and other aquatic prey are also eaten throughout the year. Late summer, fall
and winter fruits and seeds dominate, including grapes, acorns, beechnuts,
blackberries, elderberries, pokeberries, cherries, apples, and, perhaps their
favorite, corn (or whatever you have in your garbage can).
Insects can constitute a major percentage of late winter food.
Home Range: A wide range exists,
based on habitat quality and raccoon density. A study in the Smokies
found five males to have a home range of 75 acres, and three females to have a
home range of 30 acres. Chapman
and Feldhamer report maximum home ranges are normally 0.28 - 2.55 square miles
(179 - 1,632 acres). Nowak reports an average of 150 acres for males and 100
acres for females. Rue reports a home range of 2 to
4 square miles. Other sources say most ranges are between 100-250
acres, while still others show males have a home range of about a square mile (620 acres); the female, 3/4
square mile (450 acres). Home ranges overlap broadly at times,
but contact is mutually avoided and territoriality has been observed only
occasionally, in defense of local feeding area. Raccoons have been
measured to take two weeks to visit all parts of its home range.
Social Structure: Generally
described as solitary, although known to be sociable within family groups (a
mother and her young), with several seen hunting and denning together.
The most common groups recorded, except for females with their young of
the year, were pairs of yearlings. Most winter denning groups consist of two
or three siblings, already separated from the mother, who dens alone.
These young will separate in the spring. In colder habitats, the mother
and young can winter together, with the young dispersing the following
spring. Raccoons of differing ages and sexes are known
to den together in winter communal "piles" of up to 23 individuals
in a single den, usually all members of an extended family - and usually only
one adult male.
They have also been
known to be at feeding sites in numbers (30 were reported at one California
site). Adult females are more likely to
den alone than adult males. Males are polygamous, and
play no part in child rearing. The
mother will send her young up a tree at signs of danger, much like bear.
Life Cycle: Usually, one
litter of 3 to 4 per litter per year is the norm, with mating taking place
from late December to early March, peaking in February with most litters born
from April to May. Considered to be
induced ovulators, although ovulation can occur without stimulation. Estrus lasts from 3 to
6 days 9 (Nowak reports 80-140 days), with a gestation period of 63 days, weaned
by 16 weeks, with a few continuing to nurse occasionally for several months
more (so says Chapman and Feldhamer; Nowak reports 7 weeks to 4 months, Wilson reports
10 weeks) and on their own by fall, or rarely, the following spring. (Young
more commonly overwinter with the parents in the shorter season of the
northern range. In other cases,
juveniles will overwinter together without the mother. Nowak reports the
young will den either in one hollow tree or individually in nearby trees,
separating at the end of winter.)
The young are raised solely by the mother.
About half of the females can breed by the end of the first
summer, while other females (and all males) do not reach sexual maturity
until the second summer (or even the third summer for some males). Life span
commonly is two to three years, with some individuals living up to 13 to16
years in the wild. Captive
animals have lived as long as 22 years.
Dens/Nest: Uses dens for
birthing and for winter protection. Often
nests in hollow trees (12 to 30 feet above ground, in a 15” cavity), but
will also use woodchuck burrows, muskrat houses, rock crevices, or an
overturned stump. Raccoons will have several
dens they use within their home range. Raccoons don’t actually construct any
actual nest inside the dens, other than chewed and scratched wood found in the
den cavity. The same summer bedding site is rarely used on
consecutive nights, although some sites are used more than others. Pregnant
females den almost exclusively in tree hollows (averaged size 11”x14”; 9
to 36’ above ground). Ground
burrows dug by other mammals will be used in areas of scarce trees.
However, after 7 to 9 weeks after birth, the mother often moves the
young down to a ground bed, for safety (since they are mobile at this time)
and to enable them to forage on their own.
By winter, the family was back in a tree cavity (if still together).
A Virginia study found raccoons shifted from tree cavities to ground
dens during very cold winter weather. Forsyth
says winter den sites may be occupied for as long as four months in northern
habitats, losing 50%
of their body weight over the winter.
Tracks: Tracks look like miniature
human hands with five long fingers. Front feet are 2 to 3" long and almost as
wide; rear are 3 to
4" long, much longer than wide, with a 12" stride.
Scat: Scat is segmented and
can be 2- 6 inches long, ¾" diameter. Tends to be long (often broken into
smaller segments), crumbly and flat-ended and left at prominent locations,
often in accumulations. Scat is
often left in prominent places by one or different raccoons.
Remarks:
The common raccoon is native only
to the Americas.
While other procyonids have been restricted to the warm-adapted mode in
the tropics, the raccoon has become highly successful in extending it’s
range northwards as a result of it’s ability to thermoregulate, omnivorous
diet, and high reproductive potential. This
thermoregulatory evolution included a high basal metabolic rate together with
well-defined cyclic changes in body fat and heat regulation, a high level of
heat tolerance, and a high capacity for evaporative cooling.
There
is a range of color variations in raccoons, from a pale, yellowish brown to an
almost totally black coat. Albinism is fairly common. Raccoons make good pets, with intelligence equal to
that of cats and dogs. They are extremely inquisitive, and can make a real
mess if left alone in a house. Raccoons
are color-blind.
Numerous
studies have shown the raccoon to be comparable, or better, than cats in
intelligence, with only primates doing better in their rate of learning and
retention in visual discrimination problems.
(Dogs are only allowed to watch from the sidelines.)
Raccoons
are important vectors of the rabies virus in the United States, only second to
skunks nationally. In northern
Virginia, rabid raccoons have reached epidemic levels since 1961 to 1998.
Records by county during this time period confirm 963 cases in Fairfax,
655 in Loudoun, dropping to 158 in Fauquier, 157 in Prince William, 111 in
Alexandria and 94 in Arlington. Statewide,
the only other counties having more than 84 confirmed cases are Chesterfield
with 116 and Hanover with 101 (both around the Richmond, VA area).
It is believed infected raccoons were accidentally brought into
northern Virginia from outside areas of major rabies outbreaks.
Like
squirrels, raccoon can rotate the hindfoot 180° and descend a tree
headfirst. Like
canids and pinnipeds, raccoons have little erectile tissue in its penis and
relies on the penis bone, the baculum.
Raccoons
are the most valuable wild fur bearer in the US. Like
other furbearers, pelts were worth much more in the 1970’s, reaching $20,
but are worth very little today.
In
1976-77, 3,832,802 pelts were taken in the US. 846,000
were "harvested" in PA in 1981.
BACK
TO THE TOP OF CARNIVORES
Family
Mustelidae - Weasels
ARTICLES
MUSTELID EVOLUTION
Members
of the weasel family includes the weasels, ferrets, minks, martens, fishers,
wolverines, badgers, otters, stoats, polecats, tayras, and grisons. Until
recently, skunks were also included in this family. Most mustelids have long tapering bodies with short stubby legs, with
the exception of the badger and wolverine. The evolution of this body shape
has enabled the weasels to be a major predator of rodents by their ability to
enter rodent tunnels in search of their next meal and denning site. The badger
and wolverine are stocky and powerfully built, adapted for digging prey out of
the ground, rather than entering the burrows. While the badger and wolverine
are excellent diggers, the marten and fisher excel in climbing and the otters
excel in swimming. Most mustelids have evolved a
mouth with fewer but more specialized teeth.
They are mainly flesh eaters, hunting by scent, though the senses of hearing and
sight are also well developed. They dispatch their prey by piercing the base of the skull with their
large canines. Their incisors slip between the neck’s vertebrae to sever the
spinal column. Primarily solitary
animals, they are fierce and aggressive hunters, willing and able to take down
prey much larger than themselves. The smaller, slender forms usually travel by
means of a scampering gait interspersed with a series of bounds. Most have well-developed paired anal scent glands
used for defense and identification. This ability is best demonstrated in the
skunk, only recently moved into its own family. Unlike most mammals, a strong
sexual dimorphism exists, with the male often up to 50% larger than the
female. The least weasel, at a body and head length of 5 ½ to 6 ½ inches, is
the smallest of the carnivores. Delayed
implantation of the embryo occurs in many species.
Members of the weasel family have five toes; both front and rear feet.
In
general, their various colored pelages and their insulative capability makes
them valuable to the fur trade. For
example, weasels adapted to living in water must have significant protection
from the cold water, and, no coincidence, the sea otter was the most desired
– and costly- fur coat at the turn of the century (Seals and other strictly
aquatic mammals have evolved blubber for warmth in lieu of fur).
Similarly, since their long bodies have a high ratio of surface area to
body size, weasels must have a pelt of significant insulative capacity to keep
them warm. Thus, the value of mink and ermine coats.
It’s also of interest that the females, the protectors of the next
generation, have denser coats than males, and are of more value in the trade.
Of
the four species in the Mustela genus, the mink is the only one whose pelage
doesn't turn white in its winter molt. This might be a reflection of its
aquatic nature, even in winter, where a white coat would stand out. The
three others, which include the long-tailed, short-tailed and least weasel,
all are known for their winter white coats. The long-tailed and
short-tailed weasels molts to an all-white pelage with a
black-tipped tail. The black tip on the tail has evolved as a
distraction to aerial predators, who tend to focus their aim on this dark spot
rather than the main body. The least weasel does not have the dark-tipped tail. This appears to be a
function of the least weasel's small size, where the decoy isn't far enough
from the vulnerable body to afford any protection.
However,
the white winter pelage is only an effective camouflage where there is a
reliable snow cover. As a result, there is a transitional zone where the
winter coat is a mixture of white and brown (piebald). This zone is found from
central Pennsylvania through Maryland and into northern West Virginia and
Virginia. South of this zone, the winter coats are solid brown.
The short-tailed weasel has white
feet, even in its summer browns, while the long-tailed weasel’s feet turn
brown.
The
long body form of the weasels causes a relatively large loss of body heat, as
just mentioned. The inability of the
weasel to curl into a ball augments this winter heat loss. This requires a
higher metabolism (read that, more food intake) than other mammals of similar
size or weight. In fact, the
metabolism is about 10% higher than other similar mammals (Nowak reports
50-100% higher).
The least weasel, in the Arctic portion of its range, has a metabolism
400% above average; the cost of a long-bodied mammal being active year-round
in a cold environment (and it has to be active all year because it loses its
heat too fast to replace it and can’t put on enough brown fat to get it
through the winter season).
Weasels,
active all winter, and requiring a high caloric input, must take advantage of
prey whenever it can take advantage of it.
They do this by caching its prey.
Thus, the stories of weasels killing all of the chickens in the hen
house, driven by a wasteful and uncontrolled instinct to kill is not
indicative of what is occurring. What it does not eat today, it will need/eat
tomorrow. Caches of over a
hundred rats and mice have been recorded.
Additionally, the long and narrow body form creates a small stomach, in
which only small amounts of intake can occur at any one time.
Thus, the body form, extremely efficient at hunting, also creates a
body form that is extremely inefficient at eating and staying warm/alive.
Finally, the need to maintain a svelte body form in order to chase its
prey through narrow burrows, results in the birthing of small, and
necessarily, altricial young.
All
weasels have three vocalizations; a trill, a screech and a squeal.
Respectively, these calls are for communication among the species, an
offensive call to startle prey, and an expression of pain.
The
domestic ferret is believed to be a descendant of the European polecat (Mustela
putorius), and is sometimes given the subspecific name M. putorius furo.
Another study indicated that the steppe polecat (M. eversmanni) may
also be involved in its ancestry. Its domestication has been recorded as
far back as the fourth century B.C.
The black-footed ferret, thought to be extinct several
times this past century, was found surviving in a Wyoming colony in 1981, with
an estimated population of 129. When the population collapsed in the mid
80's as a result of sylvatic plague, removing its prey base, white-tailed
prairie dogs, and the accidental introduction of canine distemper into the
wild ferret population, all of the ferrets known to survive, a total of 18,
were brought into captivity. By 1989, 58 were at a facility operated by
the Wyoming Game and Fish Department and another 12 were transported to the
Conservation and Research Center (part of the National Zoo) in Front Royal,
VA. Captive breeding has been successful, with reintroductions in the
Shirley Basin of SE Wyoming in 1991. Since 1991, more releases have
occurred. At present, there are no known non-introduced wild
populations. As a result, the IUCN classifies the black-footed ferret as
extinct in the wild.
The
mustelidae family dates back to the early Oligocene Epoch of North
America, Europe, and Asia, about 34 million years ago.
More information on the evolution of mustelids can be found at Velvet
Claw.
Worldwide,
there are 25 genera and 67 species (according to Nowak's Walkers Mammals of
the World). According to the Checklist of
North American Mammals, 6
genera and 11 species are found in North America.
In the Appalachian region, this family includes three genera
with seven species: the Martes
(fisher and American marten), Mustela
(long-tailed, short-tailed and least weasel, and mink) and Lontra
(river otter).
Of
these, the American marten is questionably found as far south as
Pennsylvania. It officially is listed as "undetermined" by the
Pennsylvania Biological Survey.
In
historical times, two other members of the weasel family resided in this
Appalachian region. Pennsylvania probably represented the southern
terminus of the geographic range of the wolverine in the east. Based on
records principally from northcentral Pennsylvania, the wolverine was always
rare in the state and disappeared during the mid to late 1800's. The wolverine is
considered officially extirpated
in the Commonwealth of Pennsylvania.
While
the badger was probably a resident of Pennsylvania during precolonial times,
only one record exists prior to 1900. Since 1946, four records of the
badger exist from Beaver, Fayette, Indiana, and Washington Counties.
Whether these are escapees, releases, or a natural expansion of the native
Ohio population is not known. The
status of the badger is considered "uncertain" by the
Pennsylvania Biological Survey.
BACK
TO THE TOP OF CARNIVORES
AMERICAN MARTEN (Martes
americana) (martin, from America)
ARTICLES
Appalachian
Region Distribution:
A species questionably found in northern PA.
Listed as uncertain in PA Mammals, with two specimens collected in 1963
(Wayne County) and 1970 (Mercer County). Thought to be
extirpated in PA since the turn of the century, but acknowledging a possible
expansion southward from New York. Virginia
was probably the historic southern limit of the marten’s range.
(Audubon and Bachman did not find any in Virginia in their efforts of
1851-1854.)
Continental Range: Basically
all of wooded Canada, south into the Catskills of New York, the western
Cascades and Sierra Nevada, and the US Rockies.
Abundance: Uncommon.
Population Density: Chapman and
Feldhamer report 1.5/square mile, with deep forest habitat studies reaching
densities of 2 1/2 per square mile. Nowak reports 1
per 1.3-4.4 square miles. Peterson reports 2/square mile.
Size and Molt: Head and body:
males, 14 ½ - 20 ½
inches, 1 ½- 2 ½ lbs;
females, 12 ½ - 17 inches, 1
- 1 ½
lbs. Two molts.
Mammae: Two pair. Chapman and
Feldhamer reports six inguinal mammae in both males and females.
Habitat: Although normally
associated with northern climax coniferous
forests and swamps, the marten has been shown to be quite adaptable to a
variety of forest habitats. In the Appalachian study area, mixed forest
or mature coniferous forests with dense underbrush and a closed canopy would
be likely. Also known
from high dry ridges and mountain tops.
Active Period: Chiefly crepuscular
and nocturnal. While active year-round, less so during the winter. With fur that is not waterproof
and mats, martens will den up in rainy weather.
Diet: Martens are opportunists,
taking a wide variety of foods. Foods
fall in four categories; small mammals, birds, insects, and fruits.
Martens need the equivalence of about three mice per day.
Several sources stress the arboreal nature of the marten and emphasize
the major role of the red squirrel in the marten’s diet.
However, the red-backed and meadow vole is the staple food everywhere, with some
chipmunks and red squirrels making up a large portion of their winter diet, caught while they
sleep. Additionally, other small
mammals, and insects, birds, fruit, and nuts are eaten.
Forsyth states that 80% of its food is animal prey.
Birds and eggs are an important food in late spring and summer.
Berries and insects are common summer foods, with yellowjacket hornets
a fall prey. Tracking subnivean voles and mice in snow tunnels is typical. Will cache food, as do weasels and mink. Males lay down
more winter brown fat than females.
Home Range: About one square
mile for males and 1/2 square mile for females. Chapman and Feldhamer
report a range of 0.4 to 1.7 square miles for males and 0.4 to 0.9 square
miles for females. Nowak reports 3.2 square miles
for males; 0.9 square miles for females. Rue reports a male territory of 5
to 10 miles across and a females range of 1 to 5 miles across. NAS
reports 5-15 square miles. Degree of
overlap varies. Males have larger territories and
overlap several females. Both
sexes tend to be territorial towards the same sex.
Home ranges are often delineated by clearings, since martens will not cross
open areas if they are more than 300 yards across. These open areas hide
predators and have little food sources for the marten.
Summer travels may be 5 miles per day. Will travel
to lower elevations in winter.
Social Structure: Solitary, and
fairly aggressive outside of the breeding season. Males
and females are
polygamous with the males playing no part in child raising.
Life Cycle: One litter of about
three (1-5 range) per year. Delayed implantation enables an April birth from a
late summer mating over a three to six week period in late July or August.
She will remain in estrus for about 15 days (Nowak reports females exhibit one
to four periods of sexual receptivity which last 1-4 days and recurs at
intervals of 6-17 day during the breeding season, although some individuals
may have longer estrus). Over the week the pair are
together, several matings a day may occur, with the female being mated by more
than one male (both males and females are polygamous). After
fertilization, development is arrested for about six to eight months.
After egg implantation on the uterus wall in late January or February, the
active gestation period is 22 to 30 days (for a total gestation period of
260-268 days), with birthing taking place in late March or early April. Weaning
occurs in six weeks, with dispersal in three months.
Maturation occurs in 15 months for both males and females.
Lifespan of 15 to 19 years found in the wild.
Forsyth says 5 or 6 years in the wild; 18 in captivity.
Dens/Nest: Dens high in hollow
trees (often vacated woodpecker holes or squirrel nests), with the nest lined with grass,
leaves and moss. Will also den in logs, under rocks, tree roots, or under ground.
Also known to use abandoned squirrel nests.
Tracks: Diagnostic tracks are
diagonally placed pairs of prints (individual prints are 1 3/8"), four inches wide and up to 6 inches long
(similar to the fisher). Walking
stride of 9 inches for a male; 6 inches for a female (shorter than a fisher).
When running (actually, bounding), strides are from 24 to 31".
Straddle is 3 - 6" in snow. Unlike other weasels, it has semi-retractable claws that can be
extended for tree climbing. Although
weasels have five toes front and back, the fifth toe seldom registers, nor do
the claws.
Scat: Scat is long, thin, looks
twisted and folded and tapered on both ends; 1 to 2" long (Rue says
3-5") and 1/8 to
¼" diameter. The
marten is fond of blueberries, huckleberries, mountain ash berries and pine
nuts, which apparently mink and weasels do not eat, and these fruit contents
characterize many marten scats.
Scat is deposited upon prominent logs or rocks, often lying in a
semicircle.
Remarks:
The
marten is the most arboreal of the weasels, yet, still will spend most of its
time on the ground.
Aka pine
marten. A mink-sized arboreal weasel. One
of the most valuable furbearers in North America. Fishers are the main
predator of the pine marten.
Martens
exhibit a range of pelage colorations. A
totally yellow marten is known in the fur trade as a “canary.”
The
Hudson Bay Company traded as many as 180,000 Canadian skins each year during
the mid-1800's. In
the season of 1976-77, 130,530 were taken in North America.
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FISHER (Martes pennanti) (marten; Mr. T. Pennant - a Welsh naturalist)
ARTICLES
Appalachian
Region Distribution:
It has been successfully reintroduced in the eastern mountains of West
Virginia (Dolly Sods and Spruce Knob) in 1969, and a few have wandered into
western Virginia, Maryland and southern Pennsylvania. Introductions from New
York have filtered down into northern Pennsylvania, around the Grand Canyon
and the Allegheny National Forest. Pennsylvania
has also reintroduced fisher in 1994 to the Sproul State Forest (see Wapiti
for similar introduction information). In
1996, fishers were released in the Pennsylvania Grand Canyon.
Over 150 fishers have be reintroduced throughout north
central PA. They have been reintroduced
from Algerine Wild Area north to Colton Point State Park. The fisher
reintroduction was completed in Jan of 1997.
The
reintroduction program proved very successful in the north central region of
PA, and the WVA fisher are expanding into the southwest PA region.
As of 2000, the fisher has not reached the Poconos.
A decision not to release fisher into the Smokies was made recently.
Continental Range: Basically
Canada, with southern extensions along the west coast, the Rockies, and the
New England. (Originally found along the Appalachians as far south as
Georgia. It remained in the wild in Baxter State Park, Maine, and has
spread from there since the 1920's, when State protection was given.
Separate introductions in the Adirondacks have established a stabilized
population around 3,000 to 4,000.)
Abundance: Becoming common in
introduced areas.
Population Density: Nowak reports
that Powell (1981-82) has found densities ranging from 1 per 6.7-19.5 square
miles in preferred habitats. Other studies report 1 per 1 - 4.5
square miles. Forsyth says
fisher tend to follow a ten year cycle, a year or two behind the cycle of the
snowshoe hare (especially in areas where the hare is the primary food source).
Size and Molt: Substantial sexual
dimorphism exists, with males averaging a total body length of 36” to 48”
(including a tail which accounts for about one-third of it’s length),
weighing 8-12 pounds (records of up to 28 pounds); females, from 30” to 38”
total body length, weighing 4
½ - 5
½ pounds.
27 males from the Adirondacks averaged 37 ½"
(13.75" being the tail), weighing 8.18 pounds. 42 females averaged
31.5" (11.75" being the tail), weighing an average of 4.6 pounds.
Two
molts.
Mammae: Two pair.
Habitat: Quite adaptable.
Realistically, they are found where their prey can be found. In the
Appalachian study area, mature deciduous
forests (unlike martens) and second-growth coniferous woods are
utilized. Old growth northern
coniferous forests, near streams is common in the boreal regions of Canada.
Like the American marten, a closed canopy is required. Smaller females are a little more arboreal than males and tend to avoid
open areas.
Active Period: Most active at
night, although daytime (specifically, crepuscular) activity is not uncommon;
year-round, as well as on the ground or arboreally.
Diet: Fisher are opportunists.
More varied than martens, fishers have a fondness for porcupine, and
are a major predator of marten. The quills of the porcupine are softened
when they penetrate the fisher, and apparently do little harm to the
fisher. In
addition, favored foods include snowshoe hares, red squirrels, red-backed
voles, shrews, flying squirrels, grouse, deer mice, and carrion.
Birds, bird eggs, some vegetation, and a few berries and nuts are added on occasion.
Even raccoons, foxes, and, in one exceptional case, a lynx have been worn down
and killed by fisher. Despite their name, they do not catch fish (see remarks below).
While both sexes have winter fat deposits, males have substantially
more.
Home Range: Various sources, with 6 square
miles (females) to 8 square miles (males) being the average.
Nowak quotes Roger Powell (1994), who found home ranges of 6 square
miles for females and 14 square miles for males. Wilson
reports 7 to 30 for males; with overlapping range of females, whose home range
is 1.5 to 13.5 square miles. Rue reports
10 square miles for females and 30 square miles for males. Range
overlaps among both sexes and ages. Known to travel along
forty to sixty mile circuits within their home range (like wolves). They will
use these circuits every 4 to 12 days, traveling about 5 to 10 miles a night. It
will check every porcupine den, as well as other prey species, along this
route.
Social Structure: Solitary.
Males are polygamous. Both
males and females will defend their territory only from other members of their
same sex. Males provide no parental care.
Life Cycle: One litter per year
with an average of three per litter. Fisher mate in
March to April and give birth in March/early April.
This is possible due to a long
delayed implantation (ten to eleven months), resulting in a birth a year after
mating (an average of 352 days, including a gestation period of 30-50 days).
The females comes into estrus six to eight days after the young are born,
remaining in heat for two or three days. In
fact, she is not pregnant for only
about ten days. This means that when the young are about one week old, the
female temporarily leaves them to seek a male. Weaning occurs by 12 to 16 weeks, with the young dispersing
normally by fall. Mating of
females occurs at one year of age and produce their first litter at two years
of age. Males breed at two years
of age, producing sperm starting in February and ready to breed by early
March. Life span of 6-10 years,
with 18 years being the record.
Dens/Nest: Temporary dens, used for
cover and protection are found in hollow trees, log piles, or underground.
These dens are seldom used for more than two or three days.
Nesting dens are commonly found high in hollow trees (like raccoons) or
in rocky ledges and even abandoned beaver houses or woodchuck burrows have
been used. They do not burrow. During
good weather, will rest on tree branches, and, during cold weather, will rest
in holes in the ground or trees.
Tracks: Tracks are 2 ½" long
and wide with five pointed toes. Rue says 1 1/2 to 2 1/4" in
diameter, with all five toes showing (whereas a small dog or large cat will
only have four toes showing). Walking stride is 6-7", with a
leisurely bound of 32". Maximum stride has been measured
at 16 feet.
Scat: Often contains porcupine
quills! Similar to a martens, but is a little larger, being 5/8" in
diameter (vs 3/8"
), 4-6" long, dark and cylindrical, often segmented. May show fur,
bone, berries or nuts.
Remarks:
The
name fisher probably comes from the early immigrants noting this animals’
similarity to the European polecat, or fitchet, fitche, or fitchew.
The fisher
resembles a large, dark slender cat with a bushy, long tail. The smaller (by a
third), yet finer pelt of the female is highly prized by trappers.
Fisher
pelts brought a price as high as $345 apiece in 1920, and, as a result, fisher
were virtually extirpated from North America over the next two decades, only
surviving in remote isolated mountain pockets.
The
mean annual harvest of fisher from 1967 to 1976 for North American was 13,078.
With predators removed, porcupine populations soared in New England
states, resulting in the (successful) reintroduction of the fisher in numerous
states, including the Catskills.
The
25 fishers introduced into West Virginia in 1969 were received from New
Hampshire in exchange for wild turkey, which had been hunted to extinction in
New Hampshire. 15 were released in Tucker County and 8 in Pocahontas
County, with one pair held at the French Creek Game Farm. By 1993, an
estimated 400 fisher had populated the region, with the largest populations
found in Grant and Tucker counties. Trapping in 1972 has resulted in a
harvest of 137 animals up to 1993.
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ERMINE,
or SHORT-TAILED WEASEL (Mustela erminea) (weasel; French word for the white winter pelage)
Appalachian
Region Distribution:
Boreal. Coniferous-hardwood
forests of the north, found as far south as southern Pennsylvania.
Pre Columbian bones have been found in three western Virginia counties
and in West Virginia.
Continental Range: Canada,
western US. and northeastern US. Circumpolar,
having the largest range of all the mustelids. However, whether this is the
same species as the Eurasian species is subject to debate. Two subspecies recognized, with only one in the
Appalachian
region.
Abundance: Less common than the
long-tailed weasel.
Population Density: Can be found in
populations of up to one per 25 acres in ideal habitat. Chapman
and Feldhamer reports one per 20 acres in good habitat. However, W/H says one per 32 –160 acres in good habitat, PA mammals
reports one per 24-128 acres.
Densities will reflect the prey populations.
Size and Molt: Head and body:
males, 6 to 8 inches, 3 - 6 oz;
females, 5 to 7 ½ inches, 1 - 3 oz.
Tail length is 30-45% of the head and body length.
Two molts. The fall molt
from brown to white starts from the belly and works up to the middle of the
back. The spring molt from white
to brown, however, starts from the middle of the back and works down to the
belly. The whole process takes
approximately three to five weeks, occurring in April-May and
October-November.
Mammae: Four pair. (Peterson’s
says 8-10 mammae.)
Habitat: Woody or brushy areas near
water. Appears pretty adaptable to various habitats. Often found along stone walls and hedgerows along wood
borders.
Active Period: Primarily diurnal in
summer and nocturnal in winter (not what one might expect). Within
this context, they tend to be active day and night for brief periods of 10 to 45
minutes, with interluding 3 to 5 hour rest periods.
Diet: Mainly small mammals. Due to
their smaller size, they can’t feed on hares or rabbits like the long-tailed
weasel. Known to eat shrews,
especially in winter. Will cache
excessive kills for later food reserves.
Will feed worms to its young.
Hunting may actually be easier in winter as prey species often become
social and build communal nests to share warmth.
Weasels commonly eat communal voles and take over their winter dens.
Home Range: Ranges from 25 to 100
acres, with records from as little as 5 acres to 250 acres or more.
Chapman and Feldhamer reports about 37 acres for males and 10 acres for
females. One study found males with a range of 85 acres; females, 18 acres.
Males have larger territories and overlap several females. Ranges of the same sex do not overlap. Ermine will actively defend their territories from other
trespassing ermine. Ermine may travel 6-8 miles a night, although 3/4's
of a mile is an average.
Social Structure: Chapman and
Feldhamer says that weasel populations are solitary except during the
breeding season. However, other
sources indicate parents seem to be paired throughout the summer season (or,
even the whole year), with the male assisting in child rearing.
Wilson says females usually rear young alone, although male assistance
has been reported.
Life Cycle: One litter of an
average of 6 to 9 per year (ranges from 3-18). Polyestrous females exhibiting
delayed implantation
(arrested growth after 15 days of egg development until implantation in March) enables
one April/May litter from July/August mating (total period of delay (nine months) and gestation (30
days) of ten months). The female exhibits spontaneous ovulation, with an estrus cycle
every four weeks until fertilized. Weaned at 8 to 12 weeks. Will
reach 85% of their full size at four months.
Females breed in first fall, males not until the next summer.
It has been reported that a male will mate with the mother and
her daughters during one breeding visit (with the nine month delayed
implantation, the daughters have time to mature in size before the egg
implants in the uterus. During
mating, males grab the females by the scruff of their necks and drag the limp
female around (the original “Neanderthal Man”).
Copulation is repeated often over the course of several hours. Life span of 4-7 years.
Dens/Nest:
Will have several dens and nests throughout its range. Like the long-tailed, they
usually will make their dens in "vacated" prey tunnels.
Dens can also be found in rock crevices, among tree roots, or in a hollow
log. The male has several nests in its home range.
Since weasels can’t curl into a tight ball, large volumes of
insulation can be found piled in a weasel nest.
The fur of prey and dry vegetation is used to line its nests.
Tracks: Diagnostic tracks are
diagonally placed pairs of prints, with the exception of the skunk, who tends
to meander. Frequently the fifth toe will not register in the
tracks.
Scat: Scat is long, thin and
tapered on both ends; 1 to 2" long and 1/8 to ¼" diameter.
Remarks:
Aka short-tailed weasel. Ermine really applies to the winter white pelage
form. Also called “stoat”,
which applies to the summer brown coat. Thus,
short-tailed weasel is probably the most appropriate vernacular name.
Has a mane on its nape. Spends most of its time on the ground. Also
like other weasels, will kill their prey by piercing the skull with their
canines. Will first lick the
blood from their prey, giving support to the false notion that they suck
blood. Populations vary with
rodent pops. Voice a shrill shriek when agitated. The winter white pelts of
all three weasel species are lumped together by fur dealers and called ermine.
These are the pelts that are the traditional trim on the robes of
royalty. However, the short-tailed is the most commonly trapped of the three. Smaller
than the long-tailed weasel, but similar in markings. The difference being the short-tailed weasel has white
feet, even in its summer browns, while the long-tailed weasel’s feet turn
brown.
The
number of ermine pelts bought in the US and Canada averaged over 35,000 a year
from 1971 through 1976.
In the trapping season of 1976-77, 59,897 were harvested in the US and Canada.
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LONG-TAILED
WEASEL
(Mustela frenata) (weasel; bridled,
mask)
Appalachian
Region Distribution:
Throughout.
Continental Range: Throughout the continental US. and Central
America (a much more southern range than the short-tailed weasel).
Five subspecies recognized in
eastern US, with but one in the Appalachian
region.
Abundance: Common.
In fact, one of the most widespread carnivores of the Western
Hemisphere.
Population Density: 13-96/square mile. W/H says one
weasel per 7 acres in good habitat, or about 91/square mile. Chapman and Feldhamer and Wilson
report 16 per square mile for favorable habitats.
Rue says 1 per 160 acres, in average weasel territory. A
study in PA that had been opened up with piles of slash and abundant
underbrush found a density as high as one to 6 1/2 acres. Nowak
reports a range from 1 per 6.5 acres to 1 per 650 acres (or, about 1 square
mile).
Size and Molt: Head and body:
males, 9 to 10 ½ inches, 7-10 oz;
females, 8 to 9 inches, 3-6 oz. Tail
is more than 44% of the head and body length.
Two molts. (In PA, the northern 30% molt to white in winter, the
central and southern 70% don a pale brown coat for winter. In WVA, some of
both winter colors are trapped. Only a small percentage from MD will turn
white. Where the pelage does not turn white, it will turn a much lighter shade
of brown.) Total molting time is about three to four weeks. Rue says the spring
molt takes about two months, beginning in mid-March and the fall molt takes
about 70 days, beginning in mid-October. In the transitional area of
central PA and northwestern New Jersey, some change, some don't, and some
change partially, known as "graybacks". In transitional areas
of New York, those that did not change to white were almost always
males. Relocated specimens from both brown-coated southern
populations to the north and white-coated northern populations to the south
would retain their color molts despite the habits of the surrounding
populations.
Mammae: Four pair.
Habitat: Tends to adapt to all
habitats, both open and wooded, preferring forest and field edges and dense
cover of briars and thickets close to water, including marshes.
Active Period: Although presumed to
be nocturnal, they are often out by day.
More active by hunger than time of day.
Active year-round.
Diet: Although a generalist, they
are heavy feeders on voles, rats and mice (95%of their diet is small mammals),
also rabbits. (A Michigan study found that mammals comprised 83% of the
diet, with birds making up 9%, and insects , 7%.)
Shrews were found
to be part of the normal diet of weasels in some studies. Bats, birds, eggs, snakes and carrion are also eaten.
Can also get accustomed to poultry. Reportedly eats up to 40% of it’s
weight each day. Their killing instinct leads to occasions of excessive kills,
which they will cache for later consumption.
This leads to disastrous results in the chicken coup. Kills its prey with a bite to the base of the skull and is known to lap
up the blood. Will eat the head
and thorax first.
Home Range: Males have much larger
home ranges than females, and winter ranges are larger than summer range.
Sources vary widely, but most sources give ranges between 20 and 50
acres, with some sources as high as 400 acres for males and 150 acres for
females and as low as 16-35 for males and 5-25 acres for females.
Chapman and Feldhamer reports 30-40 acres for both sexes. Nowak
reports a range from 10 to 300 acres. Rue reports about a half mile diameter, or about 300 acres.
Males have larger territories and overlap several females.
Each sex defends their territory from others of the same sex.
One study showed both the long-tailed and ermine took ten days to make
the circuit of their range.
Social Structure: Solitary, except
when males (on occasion) supply food for young.
With a population with more males than females, weasels are probably
monogamous, leading to the idea that the male, in some cases, may help to
raise the young.
Life Cycle: As with most weasels,
delayed implantation (in this case, nine months with a 28 day
gestation period) allows for an April/May birth from a July/August mating.
Females are monestrous. The
one litter averages about four to six young (Chapman and Feldhamer says 6-9). The male will assist in child
care on occasion (perhaps commonly, depending on source). Young are weaned at
five to six weeks of age (Nowak reports 3.5 weeks) and fully grown at ten weeks.
The family disbands in fall. Female young reach sexual maturity in
three to four months, but the males take a year to mature. Life span is about
three to four years, with a captive living to ten years of age.
Dens/Nest: Like other weasels,
utilizes "abandoned" chipmunk tunnels; does not make it’s own
burrows. Dens may be under tree roots, hollow stumps, sawmill slab piles,
crevices, rock piles or buildings; often in dense brushy vegetation in or
around dry creeks and drainage ravines. Nest is a 12 inch chamber about two
feet into the burrow. The nest may consist of layers made with hair from its prey
and grass. This dude
defecates in it’s own nest as well as outside.
Tracks: Tracks are only ¾"
wide, 1" long. (Rue says 3/8-1/2" wide by 1/2-5/8" long.) Diagonal paired track pattern is diagnostic in all three weasel species.
Frequently the fifth toe will not register in the tracks. Stride is
about 15 - 18" at a leisurely bound, and 3 to 6' when moving
fast. Straddle of 3". Often piles of
discarded bones and fur of recent prey can be diagnostic around the entrance
to the weasel’s home.
Scat: Scat is dark brown and long, thin, twisted
and tapered on both ends; 1 to 2" long and 1/8 to ¼" dia.
Often found at prominent locations, marking the home range of a weasel.
Remarks:
As all weasels, they tend to be long and slender, enabling them to pursue
their rodent prey through their tunnels. The long-tailed weasel is chestnut
brown with yellowish or creamy underparts (ventral side). The tail is a little
less than half the body length; brown, with a black tip. Spends most of it’s
time on the ground, but can climb. The long-tailed weasel is extremely fast,
agile and aggressive. Their long and slender body allows them to take over
shallow burrows of their rodent/lagomorph prey for their home. Voice a shrill shriek when agitated.
In the northern
region, the long-tailed weasel molts to an all-white pelage with a
black-tipped tail, while the southern population retains its brown coat year
round.
See Size and Molt
above for details. The winter white pelts of
all three weasel species are lumped together by fur dealers and called ermine.
These are the pelts that are the traditional trim on the robes of royalty.
The
elongated body form of weasels results in a higher surface-to-volume ratio
than standard shaped mammals of the same weight.
As a result, weasels lose almost twice as much heat to the environment
as comparable sized mammals. In
addition, weasels are unable to minimize their heat loss at low ambient
temperatures by rolling into a nearly round ball assumed by most mammals.
Instead, they can only coil their elongated bodies into a flattened
disc, exposing more body surface area, thus losing more heat.
Evolution of a greater insulative pelage to compensate for the heat
loss has not occurred.
The
number of long-tailed weasel pelts bought in the US and Canada averaged over
47,000 a year from 1971 through 1976.
In
the 1976-77 season, 61,175 were taken in the US and Canada.
The
species name comes from the subspecies found in Mexico, that has white facial
markings, resembling a horses bridle. Our northern subspecies do not have
these markings.
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LEAST
WEASEL
(Mustela nivalis) (weasel; snowy)
Appalachian
Region Distribution:
It extends throughout the Appalachian mountains as far south as the Smokies
(but never actually recorded in the Smokies).
Specimens have been found on four occasions in western North Carolina
and once in Tennessee (Roan Mountain). Has been found in Big Meadows of
Shenandoah National Park.
Continental Range: To the north, it has a totally circumpolar range.
Like the ermine, whether this is the same species as the Eurasian
species is subject to debate. Only
one subspecies found in the eastern US.
Abundance: Hard to catch,
uncommon, but probably fairly common in some areas.
Population Density: 5-65 /square
miles (with 10 per square mile more common), depending on prey. Nowak reports
densities of 1/2.5-250 acres, Chapman and Feldhamer reports as many as 62 per
square mile.
Size and Molt: The smallest of the
true carnivores. Head and body:
males; 6.5 - 7 inches, 1 2/5 - 2 ¼ oz;
females, 5.5 inches, 1 1/3 - 1 2/5
oz.
The tail length is 25% or less of the head and body length.
It is the smallest carnivore in the world. Two molts. The winter white
molt does not occur in southern PA, rather, like the long-tailed weasel, a
pale brown pelage occurs. Unlike the two larger weasels, the winter white pelage
does not include a black-tipped tail.
Mammae: Three pair.
(Mammals of Virginia says eight mammae.)
Habitat: Wide variety of habitats,
including marshy areas, meadows, brushy fields, open woodlands, old fields and
pasturelands (i.e., where the mice are).
In this study area, the habitat is commonly the deep forests of the
high Alleghenies.
Active Period: Active any time of day or night, year round.
Will alternate periods of feeding with sleeping.
Diet: Feeds almost entirely on
meadow voles and mice, but will also eat birds/bird eggs and insects. Consumes about 40% of
their own body weight per day. Will
cache food when too full to eat. Like
other weasels, commonly kills its prey by a piercing bite to the base of the
skull.
Home Range: The least weasel is
fairly sedentary. Chapman and
Feldhamer reports 17 to 37 acres for males and 2.5 to 10 acres for
females. Nowak reports home ranges
of 1.5-65 acres for males and 0.5-17.5 for females.
Mammals of Virginia, NAS and Forsyth say 2 acres.
Males have larger
territories and overlap several females.
Both sexes will vigorously defend their territories from others of the same sex.
Social Structure: Solitary.
The male plays no role in child raising, and will drive the female out
of an area in times of meager food supply. Non-territorial nomadic
individuals exists.
Life Cycle: Two or three litters occur per year (having been observed in all
four seasons), with an average of four or five per litter (ranges from 3-11). Delayed implantation does
not occur in the least weasel. This
is believed to be the result of the high mortality of the least weasel and
subsequent need for a higher birth rate. Females
exhibit postpartum estrus. Males are sexually active in all months except December and January.
Gestation period of
35 days. Weaned in four to six weeks. At
three months, the young disperse, with females breeding at four months; males
at eight months (thus, females of early litters can bear young their first
summer). Most individuals
die in their first year, though a few live up to three years. Have lived to 10 years in captivity.
Den/Nest: After “removing” the
hosts, the least weasel will use prey tunnels for nesting, using the prey’s
fur to line the burrow and nest. The
burrow entrance is usually one inch in diameter leading about six inches down
to a four-inch chamber (lined with vegetation and fur from the former
inhabitant). Weasels may have more than one den in its range.
Tracks: Similar to those of larger
weasels, but much smaller. Straddle of 1 1/4"-1 3/4". Leaps
occasionally 2'.
Scat: Scat is long, thin, twisted
and tapered on both ends.
Remarks:
Smallest of the three native weasels (and, in fact, the smallest carnivore), the least weasel is about the size of a
mouse, it’s common prey. It has
only a few black hairs on the tip of it’s tail.
Males are only slightly larger than females.
Voice a shrill shriek when agitated.
Like the other weasels, the least weasel will lap up blood from the
cranial wound and will start with the brain before going on to the heart,
lungs, and ultimately, the whole critter. Also like other weasels, uses its
potent anal musk glands to mark its range.
Its range in hearing includes the lowest threshold sounds found among
mammals.
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AMERICAN
MINK
(Mustela vison) (weasel; scout, or a
Swedish word for a type of marten that lives in water)
Appalachian
Region Distribution:
Throughout.
Continental Range: Canada
and US. Seven subspecies are recognized
in eastern US, with basically
only one in our Appalachian
region.
Abundance: Common along water
courses.
Population Density: 3-21 per square
mile have been reported. While most figures are for coastal marshlands
and do not apply here, one Montana river study estimated 21 per square
mile. Presumably, densities in the Appalachian study area are much
closer to the lowest reported densities due to lack of wetland
habitat.
Size and Molt: Sexually dimorphic,
with males being 10% longer and 20% heavier than females. Head and body:
males, 15 1/2" - 18 1/2"; 2
- 3 ½ pounds and females,
12 1/2" - 15 1/2";
1
½
- 2 ½ pounds. Two molts.
Mammae: Four pair. (PA Mammals
and Nowak say three
pair.)
Habitat: Freshwater habitats
with forested or brushy areas are preferred.
During winter, will resort to inland rabbit burrows. Mink
have a semi-aquatic lifestyle.
Active Period: Nocturnal to
crepuscular, year-round, perhaps due to Man's pressure. In wild areas,
mink can be found outside anytime of the day or night. May limit activity in winter, but does not hibernate
or go through periods of torpor. Known to spend up to a week or more in
its winter den if adequate food caches exist.
Diet: Spring and summer includes
muskrat, crayfish, frogs, fish, snakes, small terrestrial mammals, and
waterfowl. A North Carolina study of 335 mink showed fish made up 61% of the
diet, with mammals , 34%, and the rest miscellaneous, while a New York study
showed muskrats in 49% of the samples, fish 41% and diving beetles, 39% of the
samples. These three items made up 79% of the diet. Winter focuses on muskrat, but small rodents make up a portion of
their diet. Will cache their prey in winter (one winter cache was found to
contain over a dozen muskrats, two mallard, and an American coot).
Also feeds well in terrestrial environs, making meals of mice, voles,
rabbits, birds and eggs.
Home Range: Chapman and Feldhamer reports a study finding one male mink in about a mile
and a half of stream length and one female covering about one mile of stream
length. W/H and Nowak report 1900 acres for males, and 20 to 50 acres for
females. Winter ranges are
smaller for both sexes. A mink may take
5 to 7 days to complete a circuit of its range, traveling about 12 miles a
night. As with
all weasels, male ranges overlap several females, with both sexes being
territorial against others of the same sex.
Social Structure: Solitary, and
unsociable, except
for family groups of mother and young. Males
are polygnous, but will often stay with the last female and help with the
child raising (bringing food to the nest).
Life Cycle: Utilizing delayed implantation, mink have one litter of four to five
(1-10) a
year in April to May. (Rue says almost all babies are born between April
25 and May 15.) Mates February through
March. (Rue says females usually breed on the exact same day
each year and it is usually the exact same day as when their mothers were
bred.) Females are seasonally polyestrus, in estrus for about 8 days.
Ovulation is not spontaneous but is induced by mating. The arrested period of embryo
development varies (from 12-43 days) depending on the time of the season. The
later the mating, the shorter the delay. The total time from mating to birth
varies from 40 to 75 days, with a gestation period of about 30 days. The young are weaned in five weeks
(Rue says 8 weeks) and stay with the mother/parents until fall, with females becoming sexually mature in ten
months (males often require 18 months), with a life span of six to eight years
(Mammals of Virginia and Forsyth say three to four years, with ten years in
captivity).
Dens/Nest: Mink may dig their own
burrow, or use one made by muskrats, beaver or woodchucks. Females are known to kill/eat muskrats and use their dens for
nesting. Mink make their one foot
diameter nest in various places, usually at the end of 5-8 feet tunnels, 1 - 3
feet underground with several 4 - 5 inch tunnels opening near the water, such as
hollow stumps, in the banks along streams, under logs and even
"abandoned" rodent tunnels or muskrat dens. Nests are lined with
grass, plant fibers, feathers, and fur. Male
dens have no nests. Multiple dens
throughout the mink's range are common (one family within a 77 acre range had 20 dens). Nests are
normally lined with grasses leaves, feathers, bits of fur and remnants of
prey.
Tracks: Tracks are 1 ¼" long
and wide with five pointed toes. Diagnostic tracks are diagonally placed pairs
of prints. While bounding leisurely, the stride is from 12 to 18 inches,
with a full speed distance of about 24". Tracks at a slow speed
form a general square, while high speed tracks form the traditional weasel
diagonal line.
Scat: Scat is dark brown and long, thin,
twisted and tapered on both ends; 1 to 2" long and 1/8 to ¼"
dia. Normally cylindrical and sometimes segmented scats, 5-6 inches long.
Feces are deposited in
piles near the den site.
Remarks:
While mink cannot climb as well as marten, swim as well as otter, or fit into as
small a rodent hole as a weasel, it is a composite of all of these specialists,
and does well in its generalist's role among the weasel family. It can
swim underwater for up to two minutes, traveling up to 50 feet.
Mink are slightly shorter and heavier than pine martens (which makes sense,
with the mink needing a more compact body to conserve heat in its aqueous
environment, while the marten needs to be light and long to chase red squirrels in tree
tops). Mink are semi-aquatic
mammals. When irritated or excited, the mink expels a very odoriferous liquid
from it’s anal glands, perhaps as obnoxious as the skunk, but cannot project
it. Larger than the weasel, the mink is a solid chocolate brown with a white
chin and occasional white spots on the throat, chest and belly. The winter
coat is highly prized and is much thicker and heavier than the summer coat.
Various color variations are raised on mink farms.
Courtship
is quite violent and prolonged, with the male savagely biting the female’s
neck.
They
are known to purr when content.
Over
4,500 mink were "harvested" in PA in 1982-83, and 40,000 were
harvested in New Y0ork in 1976, although most of these were from mink farms
(~90%). In 1976-77, 320,823 were caught
in the US, with another 116,537 caught in Canada. Mink farms peaked with high pelt prices in the 1960s, with about 11
million pelts annually harvested in about 7200 mink ranches.
The highest prices for mink was in 1966 for the "black willow"
color, with the Hudson Bay Company auctioning off the entire output of these
pelts for an average price of $450 each. Forty were deemed to be extra
special and sold for an average price of $1100 each. But like other furs, those of mink are nearly worthless today.
The
sea mink, Mustela macrodon, was
another species found on the east coast of the US that has been hunted into
extinction. The last one was
trapped at Campobello Island in New Brunswick in 1894.
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NORTHERN RIVER OTTER (Lontra
canadensis) (otter; from Canada)
ARTICLES
Appalachian
Region Distribution:
Theoretically, throughout; but may be extremely rare in the mountainous
region. Otter have been reintroduced in all five of this Appalachian
region states. Gone since 1936,
reintroduced into the Smokies in 1986 and 1988 (Abrams Creek and the Little
River), followed by introductions in Cataloochee Creek and Hazel Creek in
1992. Finally, 100 additional
river otter were released throughout the Park in 1994, ending the restocking
efforts in the Park. More information on
North Carolina and Pennsylvania restocking can be found in the ARTICLES
above. Expanding
naturally throughout Virginia, although western VA has been restocked along
the Cowpasture River (17 released in 1988).
In WV, 30 otters have been released in 1984, some to the Little
Kanawha River. Otter, common in the Chesapeake Bay basin, have been
reintroduced into the western counties of Maryland (Garrett and Allegany).
Continental Range: All of
Canada and US. Along with the timber wolf and beaver, the river otter occupied
one of the largest geographic areas of any North American mammal. Since
the river otter has been reintroduced, the subspecies would reflect their
source, with two subspecies being found native to eastern US.
Abundance: Rare in this study area, except where
reintroduced. Not found in food-poor mountain streams.
Common in coastal plain.
Population Density: Restricted to
larger streams in the Appalachian study area, densities best approximating
these conditions are based on linear stream lengths. For example,
Chapman and Feldhamer reports studies finding otter densities of one animal
for each 1.2 to 1.8 stream mile. Other studies indicate ~2 / square mile of surface water, or one per
every 2- 3 linear stream miles. In prime areas of the otters' range
(outside of this Appalachian study area), one study
suggests 5 per 40 square miles in favorable Ontario habitat.
Rue reports 1 per 20/25 square miles is considered a good
population.
Size and Molt: Head and body 24 to
33 inches; Males, 15-30 pounds. Females, 10-25 pounds. The
record is a 50 pounder. Females are about
one third less in size and weight.
Mammae: Three pair. (Petersons’
and Rue say two pair.)
Habitat: All aquatic situations.
This includes swamps, marshes, rivers, and lakes.
Active Period: Nocturnal or
crepuscular, or even diurnal. Active
year-round.
Diet: Carnivorous diet consists of
fish (including trout), crustaceans (crawdads and snails), amphibians (frogs
and salamanders), reptiles (snakes and turtles), mammals (voles, muskrats and
even young beaver), birds and other animals. They are not highly selective of
the fish they catch, preying mostly on slow, abundant fish such as suckers,
catfish and carp. (In the Smokies
- Abrams Creek - crawdads make up 95% of the summer diet.)
Some grasses are included in their summer diet.
Will cache extra food (Rue says no!). Otters
are known to use their noses to dig out hibernating frogs and turtles. When
eating, otter bring the food out onto a rock to eat.
Home Range: Varies with food supply
and breeding time. Ranges are larger in
winter and during the breeding time. Male home ranges are much
larger and variable than females, with considerable overlap among opposite and
well as same sex ranges. Some
range may contain three to ten linear miles of river shoreline.
Other studies show over the course of a year, an otter may range over
50 to 100 linear miles of streamline. Another
found a home range of about 6 square miles, with home ranges of a mother and
her young ranging from a half a square mile to 4.2 square miles.
As with all weasels, male ranges are larger and overlap several females, but no other
males. Studies of European river
otter in Sweden reveal both male and female otters maintain territories within
their home ranges that are defended and maintained exclusively by the resident
otter. Such territoriality may be a function of population density, and hasn’t
been clearly seen in northern river otter populations. It takes about 7
to 10 days (or even 2 to 4 weeks, according to some researchers) for the otter
to complete a circuit in its range.
Social Structure: Unlike other
weasels, very sociable, living in family groups year-round.
Families normally consist of the adult female accompanied by her pups.
Usually, the pups stay with the mother until the female would give birth
again, although, occasionally the pups of the previous breeding season will
stay with the mother and newborn pups. Adult males are normally
solitary, although some studies have
found males to rejoin the females and young when the cubs are about six months
old. Usually, family groups are isolated, but occasionally, two families will
co-mingle. During breeding season,
males will spend most of their time with one female, although they will mate
with others (polygyny).
Life Cycle: One litter per year, averaging two to three
(1-6) per brood,
with birthing normally around March or April, subject
to a delayed implantation of 240 – 280 days (not including a gestation
period of about 50 - 60 days, which begins in January or early February). The
mother mates immediately after giving birth (like the post-partum estrus of
the rodent family), with ultimate birth about a year later. Although the male
is around prior to birth, it usually is excluded from the birthing chamber for the
first several (up to six) weeks (Nowak reports up to six months). After
this time, the father returns to help supply food to the kits. Young are weaned about 14 weeks of age (Rue says 6 - 8 weeks)
and learn to swim and travel at
about this time. The kits stay
with the parents until fall or the following spring, some females capable of
breeding at that time, but most females require two years.
Males are not sexually mature for two years, however, males do not
successfully mate until territories are established, often not until five to
seven years of age. Life span of
8 to 12 years in the wild, with a 23 year-old known in captivity. Mating
usually occurs in the water.
Den/Nest: River otters do not excavate their own dens.
Numerous dens and temporary shelters will be used in the course of a
year. Dens are made in the banks of their environments, often using abandoned
beaver (or nutria) burrows, or utilizing hollow logs, or log jams, with the
nest chamber well above water. Each
den has an underwater entrance with a tunnel leading to a nesting chamber.
Nests will be made of plant material.
Otters will on occasion build a nest-like structure in aquatic
vegetation. Openings may include
both an underwater and above water entrance.
Tracks: Tracks are 3 ½" long
and wide with five pointed toes and a tail-drag in snow or mud. Otter
slides are not normally seen, but are 8" wide or more if heavily used.
Scat: Scat consists of fish scales
and not much else in commonly used "scent mounds". There may be as
many as 30 to 40 of these scat sites along commonly used trails along the
watercourses. When well-formed, they are usually in 2 or 3 segments, about
3/4" in diameter. Their presence can be confirmed by noting their "latrine
sites" or "scent mounds".
Remarks:
Otters are the
closest things to seals that our fresh water environments contain.
They are highly intelligent. They
can be readily trained to perform a wide variety of activities, including
capture and retrieval of objects from land or water.
One captive otter learned to retrieve waterfowl by watching a Labrador
retriever perform. They tend to
make games of every activity. They
also have exceptional memory. In
one account, a European river otter was trained to operate a self-feeding
device, and after a 26 month absence, when re-introduced to the device,
immediately operated it successfully.
They
also have a reputation for being extremely playful animals.
In captivity, they exhibit repetitive actions, such as sliding on mud
bands or in the snow. One otter was noted to chose a small pebble, carry it to the
water, swim out and drop it, and before it reaches the bottom, the otter will
dive and come up underneath the stone and catch it on the flat top of its
head, continuing to balance the stone on it’s head as it engaged in a series
of underwater acrobatics. Otters
will wrestle together, play tag and duck each other in the water.
An otter will play hide-and-seek with a dog in a pile of straw.
Gregarious
and playful, the river otter anthropomorphically shows that otter have more
fun than any other mammal. “Tobogganing”
is a favorite sport, both in winter and summer.
Otters
can remain underwater for up to eight minutes.
The river otter, like
all weasel, have potent musk glands, very noticeable if one is trapped.
Winter
pelts are highly valued by fur dealers.
It is famed for its luster, strength and durability and is considered to
be 100 percent on the furrier's scale, the standard by which all other furs
are judged.
In
the 1976-77 season with 26 states reporting, 32,846 were taken in the US, with
another 19,932 harvested in Canada. Louisiana is the largest provider of
pelts in the US.
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Family
Mephitidae - Skunks
North
American skunks are well-known for their anal scent glands, which can be
sprayed at potential predators. They
all have black and white color patterns that serve as a warning to predators.
Additional behavioral patterns give warning to all of the skunks’
intentions (which all predators can easily read – with the possible
exception of dogs). Skunk anal glands can “shoot” its musk two or three times
before emptying out its load. It
then only takes about a half an hour to “reload”.
It
is not surprising that, with such a powerful built-in deterrent to predators,
skunks are not known for their intelligence, strength, speed, or stamina.
The skunks have five clawed toes on each foot.
Until
recently, skunks were classified as a subfamily of the Mustelidae family,
along with the weasels. However,
new DNA studies (1997) have classified the skunks into their own family, the
Mephitidae. There are nine
species in three genera in this family occurring in the New World.
Two additional species of Oriental stink badgers, genus Mydaus,
are included in the Mephitidid family.
There
are six species of skunks in North America representing three genera
(according to the Checklist of North American Mammals).
Two
species, each representing different genera, are found in this
Appalachian region.
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EASTERN
SPOTTED SKUNK
(Spilogale putorious) (spotted
weasel; a stench)
Appalachian
Region Distribution:
Northern limit is south central PA.
Continental Range: Most of US, but absent in the NE and north
central states. Not found in the piedmont or coastal plain in the middle
Atlantic states. Also found throughout most of Central America.
Three eastern US subspecies
recognized, with only one in the
Appalachian
region.
Abundance: Common in
mountainous areas.
Population Density: 5-23/square
mile.
Size and Molt:
Head and body 17 to
21 inches long for males; 16” to 21” for females.
1 to 2 ½ pounds, with males
averaging 1 ½ pounds and females
1 pound. The spotted is the
smallest of native skunks. Northern
individuals are larger than southern (the Appalachian region is in the
northern range). Males are about
10% larger in length than females. Two molts.
Mammae: Four pair.
Habitat: Prefers drier habitat than
the striped skunk. In the northern limits of its range of VA and PA, the
spotted skunk is found in dry, rocky mountainous areas (rock talus or scree
slopes). South of this area,
prefers open forests, brushy areas and fields, avoiding wet areas.
It is also fond of farmyards.
Active Period: Highly nocturnal,
year-round, with periods of dormancy in severe winter weather. It is
credited with being more nocturnal, quick and alert than the striped skunk.
Diet: Like the striped skunk, its
diet is opportunistically omnivorous, with perhaps a larger percentage of
insects and mice than the striped skunk.
In summer and fall, it eats insects, small mammals, fruit, corn, birds,
and bird eggs. Winter diet may be
90% small mammals, including cottontails and rats.
The spotted skunk is much quicker and more agile than the striped
skunk, resulting in rodents making a larger percentage of their diet.
Their climbing abilities also allow for more bird young and eggs than
striped skunks. Spotted skunks
are also known to raid weasel caches, but will not cache food themselves.
Spotted skunks have been observed stealing chicken eggs, picking them
up and dropping them on hard surfaces, or kicking them against hard objects,
in order to lap up the contents.
Home Range:
Somewhat nomadic without a home range. Figures
range from 16 acres to 25-740/acres. W/H and NAS say they have no identified
territories (similar to opossum). Wider
summer range than winter (which in one study was only 2 acres).
Home range of females is much smaller than
males. Nowak reports a winter home range of about 150 acres.
Social Structure: Solitary, but not
territorial. More
social than striped skunks, they are more likely to den together during
winter. Males can be either
polygamous or monogamous. Males don’t help with
child-rearing.
Life Cycle: Usually only one litter
with an
average of four or five kits (2-6) are born per litter, the largest recorded being
7. A second litter
in late summer or early fall is known under favorable conditions. Most
sources (including Chapman and Feldhamer and Nowak) indicate spotted skunks have a
short delayed implantation period of about a week or two, with a March/April
mating and a May/June birthing (total period of 50 - 65 days). W/H and
NAS say
there is no delayed implantation associated with the 50 - 65 day gestation,
while Mammals of Virginia says a delayed implantation of 180 to 200 days with
a 30 day gestation period is the norm (which, I believe, was information
gathered on the western spotted skunk, S. gracilis, when it was
considered co-specific with the eastern spotted skunk). Females are polyestrous, with
spontaneous ovulation upon copulation, having estrous cycles from September
through January. If communal winter denning has occurred (which involves one
male and a number of females), the male will mate with the den mates.
Kits weaned in 8 weeks, and
on their own by the first fall. They are able to emit musk when only about 46
days old. Most kits reach sexual
maturity in 10 to 12 months, but a few males can breed in September of their
first fall, when five months old.) Life
span is five to six years (Forsyth says ten years).
Den/Nest: Usually make their own
dens (with, or without burrows) in brush heaps, rock piles or under building
foundations, but also uses woodchuck burrows and are known to shelter in
trees. Dens do not
appear to have a specific ownership, rather, they share a communal use by a
local population. They usually have more than one den site within their home
range. Of course, females with
young will maintain sovereignty of a den during the spring. Nests are of grass or hay.
Skunks not only have reportedly denned with raccoons and opossums, but have
curled up together for mutual warmth.
Tracks: Two types common: while
hunting, the hind feet are placed in the tracks of the front, 4 to 5 inches
apart, or while at a half-bounding gait, leaves tracks in pairs, like weasels,
with pairs about 9 to 15 inches apart. Hindprint is 1 1/4" long.
Scat: Usually found along skunks’
runways, about 1/3 - 1/2" in diameter and irregular in shape, with scat
accumulations occasionally reaching a depth of 2". Scats
are indiscriminately scattered about a den site. Spotted skunks are less
inclined than striped skunks to make latrine sites.
Remarks:
Aka civet cat, this small, squirrel-sized carnivore has various white stripes
and spots on its black coat. This genera is the only skunk having a broad,
triangular nose patch and more than four white body stripes. The proportions of black and white varies significantly. The
black and white coloration, also found in porcupines, seems to be a “flag”
that can be easily seen, both day or night, warning potential predators to
avoid confrontation. This
strategy usually succeeds.
The
spotted skunk is more active, agile and alert than the striped skunk.
They are excellent climbers (much better than striped skunks).
They
also eat four times as many mammals as the striped skunk.
The
unusual defense of the spotted skunk starts with the skunk stomping the ground
rapidly with its front feet. The
next stage includes doing a series of handstands with the rear end and tail
held straight up in the air. If the intruder hasn’t caught on by now, the
spotted skunk will either drop to all fours, or remain in its handstand
position, and let go with the spray. (It is by this time that most dogs will
usually catch on as to what’s happening).
The potent musk glands secrete the spray 12 to 15 feet in distance,
which is recognized by many to be a more sickening and sweeter spray than the
striped skunk (also described as being “sharper and more pungent”, or “similar
to highly concentrated onion extract”). The sulfide spray (mercaptan) can cause
momentary blindness. However, the
smell doesn’t last as long as that of striped skunks.
They
can be easily “deskunked” with a pair of sharp scissors by snipping off
the ends of the two musk ducts that open just inside the vent of each side.
The
pelt of the eastern spotted skunk is the finest and silkiest of the skunk
furs.
In
the 1976-77 trapping season, the reported harvest in the US was 41,952.
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STRIPED
SKUNK
(Mephitis mephitis) (bad vapor
coming out of the earth)
Appalachian
Region Distribution:
Throughout.
Continental Range: Throughout North America, from southern Canada to
northern Mexico.
Five recognized subspecies in
eastern US, of which, two occur in the
Appalachian
region.
Abundance: Common.
Population Density: Nowak
reports 1.8-48 per square mile, with most ranging from 5-12.5 per square
mile.
Size and Molt: Head and body 14 -
22 inches, 4
- 10 pounds
(record is 16 pounds).
Males somewhat larger than females. (One study of 197 adults averaged 5.7 lbs
for males and 4.4 for females.) One molt beginning in April with the
shedding of the underfur followed by the guard hairs in July, at which time
both the underfur and guard hairs are replaced, from the head to the tail,
over the next six weeks.
Mammae: Variable; from 10 to 14.
The usual number is 12.
Habitat: All habitats, but
highest concentrations are in brushy or open wooded areas and along
forest-field margins.
Active Period: Basically nocturnal
or crepuscular, usually late day and night, but can be active in the day as
well. Does not hibernate; can be seen on warm winter nights. Otherwise, can
spend long periods of winter in its den (up to three weeks, or even up to 100
days in northern range), living off its fall-accumulated brown
fat (fat can make up 30-50% of total weight in late fall).
Female and young tend to den
the longest.
Diet: Unlike the mustelids, skunks
are omnivorous, eating equal parts of animal and plant matter. Much of their
eating habit consists of smell and digging up its prey.
Spring menus include voles and beetle grubs.
Summer diet is insects and their grubs.
Bird eggs are consumed by biting off one end of the egg and licking out
the insides, leaving the eggshell intact. They also prefer wasps and bees and
yellow jackets, despite observed stings on the body, tongue and in the mouth.
(They can be a pest for beekeepers. Skunks
will roll the bees in their tough paws. This
rolling technique is used to process hairy caterpillars.) Fall diet includes fruits (especially persimmons), berries,
nuts and vegetation. Winter includes small mammals. Other foods include
salamanders, lizards, crayfish, earthworms, clams, and carrion. Also known to deskin and eat toads and to eat small domestic
cats. It is said overturned
cow patties in a pasture is the work of a skunk looking for grubs.
Home Range: Varies
considerably, with studies ranging from 25 acres to 1250 acres (Rue reports
2500 acres-4 square miles). Males wander over a large area in
autumn. Will not fight others to defend their home range.
Overlapping ranges are common among skunks.
Social Structure: Polygamous and
solitary, although known to communally den in winter. They are tolerant
of other skunks. Females may den together
in winter with one or two males in the northern limits of their range, but the
males are more apt to be solitary in this Appalachian study area.
A record of 20 skunks (19 females and one male!) have been observed in
one winter den. Usually there averaged one adult male and 6 females per
den.
Life Cycle: Only one litter per year
occurs, with an average of four to six (Chapman and Feldhamer says 6-8,
ranging from 2 - 10) per litter (four in the first litter).
The record brood was eighteen, set in PA.
A second brood can occur in cases of a loss of the first litter.
The limited breeding period is in
February/March, with a short delayed implantation (about 19 days) a part of
their life cycle. Gestation period of about 65 days after implantation.
Females are usually monestrous but might have a second estrus a month later if the first
pregnancy is not successful. Polygamous males go looking for females in their dens to find the ones having
their four to five day period of heat and do not help in child rearing. Males
exhibit aggressive behavior for about 36 days from early February to early
March. Young, born in May or early June, are weaned in 6 to 8 weeks, staying
with the mother until fall, following her in single file (most disperse in
fall, but some skunklets - gotta love those names, also known as kits -
overwinter with the mother). Many
road kills in fall when the young disperse.
Up to 90% of the juveniles don’t live through the first winter. Young
kits can breed in the following spring. Life span is five or six years. Wilson says 2 to 3 years in the wild; up to ten in
captivity.
Den/Nest: Has several dens with
several entrances and will
sleep any place in mild weather. Will use abandoned
woodchuck/fox holes, or can dig it’s own burrow. Will often have several
well-concealed entrances (8" diameter burrows) leading 6 to 20 feet (or
more) to one to three nest chambers 3 to 4 feet below ground.
The nest chamber is usually 12” to 15” in diameter with flooring of
grasses and leaves. Females with young
able to travel will change dens every one or two days. Summer dens
without nests can be less than 20” underground or above ground, in hollow
logs or rock piles. Winters in
former woodchuck or badger burrows. Known to share winter burrows (but separate chambers) with
opossums, woodchucks, and cottontail rabbits and other skunks. Rue says
they actually will curl up together to share warmth.
Tracks: Front tracks are 1"
long and wide (hind feet 1 ½" long and 1" wide) with five pointed
toes on front and rear feet. Stride of 4-6". The diagonal loping tracks are diagnostic.
Scat:
1.5
- 5" L x 1/2 - 3/4" W, with rounded or flat ends, usually very dark,
composed of mostly insect parts.
Remarks:
Striped skunks have
a quite variable pelage, usually consisting of two white stripes of varying
lengths and widths, but can be one stripe; large or very small.
Albinism is known to occur, but no melanistic skunks.
The
skunk uses a wide repertoire of behavioral actions to warn potential predators
prior to the actual spraying. This
is because, like the venom of pit vipers, the physiological cost of
manufacturing the musk is an energy drain.
This makes skunks hesitant to spray.
First, it will arch its back and walk toward the intruder. It hisses, clicks its teeth, stamps its front feet and
occasionally uses the handstand in its defensive posture, but that behavior is
much more common in the eastern spotted skunk.
More often, the striped skunk will bend its body into a U-shape with
its head and rear end pointed in the same direction and let loose.
The
famous musk glands can shoot the tiny acrid, pungent spray up to 15 feet.
It can be atomized or sprayed as a liquid. About one tablespoon of scent is contained in each gland. The
spray can cause temporary blindness and nausea. Despite numerous sources that indicate if the tail is held
down, the musk glands cannot act, holding a skunk by its tail does not prevent it from being able to spray.
Most skunks will not spray when held this way, but some will (do you
feel lucky?). Young are able to emit their spray at 8 days, but cannot aim until
their eyes open at 24 days. Two
well-known methods for removal of the odor are to soak the clothing in tomato
juice or ammonia. A chemist
recommends a concoction of hydrogen peroxide, baking soda and soap to counter
the thiol compounds responsible for the odor.
His formula is one quart of 3% hydrogen peroxide, ¼ cup of baking
soda, and one teaspoon of liquid soap. Soak
and scrub in this and then wash off with tap water.
Another recommendation is to bury the clothes for a month. A dilute solution of chlorine bleach also works for some
people.
Neutroleum-alpha
is probably one of the most useful chemicals for alleviating skunk scent.
(Hospitals may be the the best source of this product.)
Moth
balls or naphthalene crystals are generously used to repel skunks from attics
or beneath buildings.
Its
musk may be used as a perfume base once the odor is removed.
The refined fluid has a great capacity to fix and retain aromas.
The active ingredient is a sulphide called butylmercaptan.
Skunks
are preyed upon by great-horned owls, who, although having terrific hearing
and sight senses, suffer a bit in the olfactory sense. (In fact, it has been
recorded by researchers, that practically all great-horned owls in the skunk’s
range smells of skunks, one of its main prey items.) One owl nest had 57 skunk
carcasses beneath it. Of course, dogs will
attack skunks, usually just once. It
is not surprising that, with such a powerful built-in deterrent to predators,
skunks are not known for their intelligence, strength, speed, or stamina.
Striped
skunks conserve energy in winter through several practices including
development of a layer of brown fat, denning communally, reducing activity
levels and reducing body temperature.
About
50% of all confirmed rabies come from skunks (the leading carrier in the US,
ahead of raccoons). Rabies can be
either the “furious” kind or the “dumb” kind, normally associated with
bat rabies.
At
the turn of the century, skunk pelts were sold in the fur industry as “sable”,
but only after the white stripes were removed.
Skunks
make good pets if surgically descented by removal of the scent glands.
In fact, skunks were popular as pets in the early 1900’s, but sold
under the name of “sachet kittens”. Today,
they are illegal in most states as pets, due to their susceptibility of
transmitting rabies.
In
the 1976-77 season, 175,884 pelts were taken in the US and Canada.
BACK
TO THE TOP OF CARNIVORES
Family
Felidae - Cats
Felids
include the lynxes, lions, leopards, jaguarundi, tigers, bobcats, mountain
lions, ocelots, and cheetahs. They are separated into two basic groups; the big cats (genus Panthera) and the small cats (genus Felis).
Small
cats purr---bobcats, ocelots, lynxes, and even mountain lions.
(Kenneth Logan, with the Hornocker Wildlife Institute has been in a
cage with a purring mountain lion, describing the sound as “thunderous”.)
Purring is the main distinction between the two genera (the other
difference is that the eyes of the small cats have pupils that narrow to
vertical slits). The big
cats (true lions, tiger, leopards, and jaguars) can't purr, but can roar.
The
cheetah is in it's own genus since it can't retract it's claws completely.
It is also considered a big cat that purrs and can’t roar.
It is considered to have changed little from the primitive stock that
gave rise to all other cats. It is apparent that both the cheetah and
mountain lion evolved from a common ancestor in North America.
Cats
are the ultimate carnivores. With
no molars behind the carnassial scissor-teeth, cats are committed to a life of
carnivory. The epitome
of these carnivores was the saber-, scimitar- and dirk-toothed cats that
roamed North America up until the end of the last ice age.
At that time, the warming environment caused the extinction of the
large herbivorous megafauna, and with it, the demise of these predaceous
specialists, unable to compete for a changing prey base.
A
life of carnivory has the cost of battle with the prey and its attendant
dangers. Prey can also be hard to
find. However, meat is easy to
digest and is energy rich. Conversely,
herbivores can always find food, but must eat large quantities of the
low-nutrient plant matter, requiring large stomachs and the services of
bacteria to break down much of the hard to digest woody material.
Herbivores must also commit energy to the production of enzymes that
enable the mammals to overcome various toxins produced by the plants as
defense mechanisms. They also
must seek out salt sources, which are basically absent in vegetable matter,
but adequate in meat.
Master
hunters, their senses of smell and hearing in felids are acute. They have larger eyes
than most mammals that are pointed forward to provide binocular vision and
depth perception vital for hunting. Their night vision is six times better
than man. They are one of only a few mammals that have color vision. Their highly sensitive whiskers also help them maneuver at night.
They are also known for their remarkable sense of balance that enables them to
always fall on their feet. Recurved
horny projections on the tongue aid in grasping food. Cats have four toes, front and rear. Unlike the canids, their
claws are retractable, serving as highly efficient meat hooks and slicing
knives. Their long canines help them grasp their prey and their carnassial
teeth help them shred and rip the flesh apart. Cats are excellent climbers and
can readily climb trees to escape danger. Cats are not long distance hunters
like the canids. However, they
are excellent sprinters. Hunting
is done by stalking or lying in ambush for prey to approach. Their short
snouts enable the cat to breathe as it bites and buries its teeth into the
neck and throat of its prey.
Both
of our native cats (bobcat and mountain lion) are territorial, using urine and feces to mark their
territories. Rubbing and
scratching posts are another way of marking territories.
They are both solitary and nocturnal, like most cats.
It is
believed that our domestic cats are derived from the African wild cat (Felis
silvestris libyca), who
befriended the Egyptians some 4,000 years ago, and has been keeping man as
their servants ever since.
The cat was the object of a passionate cult in ancient Egypt, where a city,
Bubastis, was dedicated to its worship. The followers of Bastet, the
goddess of pleasure, put bronze statues of cats in sanctuaries and carefully
mummified the bodies of hundreds of thousands of the animals. The
veneration of cats in Egypt intensified about 3,000 year ago and persisted at
least into Roman times.
The domestic cat is known to decimate native
wildlife, especially songbirds. For example, two cats were released on a
French island in 1956. As of 1994, from these two cats, there is a
population of 10,000 cats on the island, consuming an estimated 3 million
birds per year. So say the authors of that study.
Historically,
the lynx (Lynx candensis) existed in
PA (Audubon and Bachman 1852). However, only one specimen has been collected; in 1923 from Tioga County.
Being highly reliant on its main prey, the snowshoe hare, the lynx
undergoes cyclic fluctuations in population in response to the hare’s 9 to
10 year cycle. As the hare
population begins to fall, the range of the lynx expands greatly in search of
food. It is at these periods that the lynx would most likely be
found in PA.
The
lynx has been assigned the status of “undetermined” in PA, and will not be
discussed in this study.
The lynx is making a marked recovery in Maine since the early 1990's.
Records prior to 1895 document the lynx in Garrett County, Maryland.
No verified records exist for Virginia. Charlie
Sisk, a mountaineer of the Shenandoah National Park area, purportedly sent a
specimen to New York, which was confirmed to be a lynx.
The
earliest representatives of the Felid family are known from
fossils dating back to the Late Eocene Epoch (38 million years ago) in North
America and Europe.
According
to Nowak's Walker's Mammals of the World, worldwide,
there are only 4 genera, representing 38 species of cats. These four genera are Felis (small cats, lynxes, and cougar);
Neofelis (the single species of clouded leopard); Panthera (big
cats-leopards, tigers and lions); and Acinonyx (the single
species of cheetah).
According to the Checklist of North American Mammals, there are
7 species in five genera in North America alone (8 species in six genera, if you include the feral
cat).
The cats are represented in the Appalachian study area by the bobcat
and, in some form, the mountain lion.
BACK
TO THE TOP OF CARNIVORES
MOUNTAIN
LION
(Puma concolor) (cougar; one color)
ARTICLES
Appalachian
Region Distribution:
Many reliable reports document the existence of mountain lions in the remote
areas of the Appalachians, including the Shenandoah National Park. Perhaps the
real questions do not center around whether the mountain lion is found in our
region, but, rather, do these sightings represent a natural migration of
native stock (versus human release of individuals) and whether it is possible
for a population to sustain itself on a long-term basis in the Appalachians.
While many reported sightings come from the western counties of VA and the
Southern Appalachians, especially in the Cataloochee area of the Smokies
(North Carolina), park wildlife officials maintain that most of these are
probably escapees from captivity, released outside of the park.
Currently, there is no evidence to support the assumption that viable,
sustainable populations exist in eastern North America, except in southern
Florida and northern Maine and into Canada. See remarks below for
further discussion.
Continental Range: Found
from Canada to the southern tip of South America, the cougar has the largest
range of any mammal in North America. Two subspecies exist in eastern
US; the Puma
concolor couguar,
of NE US and Canada, and formerly the rest of eastern US, and the P. concolor coryi,
the very Federally endangered Florida cougar.
Abundance: Eastern subspecies (Puma
concolor cougar) listed as a Federally designated Endangered Species.
Population Density: In its western
range, 1 per 20 to 40
square miles of suitable habitat, although Nowak reports a Idaho study that
found a density of 1 per 14 square miles.
Wilson
reports 1 per 8-50 square miles.
Size and Molt: Head and body 42 to
54 inches, standing about 30" high at the shoulder. 80 - 230 pounds (averaging
176 to 198 for males and 75 to
176 for females). The heaviest on record was a 220 pounder shot by Teddy
Roosevelt, but it is believed that many individuals are larger (Shedd reports
a 275 pounder, Rue, a 276 record from Arizona). Adult weights are reached in two to four years.
Mammae: Peterson’s says four
pair, but only three pair are functional.
Habitat: Remote areas, far removed
from human impacts (and dogs). The mountain lion is restricted largely to the
habitat of its primary prey; the open forests of the white-tailed deer. Marshes
and swamps are also preferred habitats. Audubon and Bachman (1851) associated mountain lion habitat with the
canebrake wetlands of the southeastern US.
Active Period: Nocturnal and
crepuscular, year-round.
Diet: The mountain lion is one of
the most specialized carnivores. Their
preferred diet includes mainly deer as well as porcupine.
As the cottontail is to the bobcat, deer are to the mountain lion. Other small mammals, such as rabbit, rodents, raccoons et al, seem to
be minor, opportunistic dietary items. Must
have large prey which they can cache and feed on for several days between
kills. Wilson and Rue note a cougar kills about 48 ungulates per
year, or about one every 7 to 10 days. Nowak reports one deer every
3 days for a female with large cubs to one every 16 days for a lone
adult.
Home Range: Figures mentioned here
apply to western populations, since no data on eastern populations exist. Males require a home
range approaching 100 + square
miles. Females require only about 75 square miles.
Chapman and
Feldhamer report Seidensticker's Idaho study finding a home range of 181
square miles for males, 78 square miles for females with kittens, and 135
square miles for females without kittens. Wilson reports an average of 108 square miles for males and 54 square
miles for female home ranges. Rue
reports 30-60 square miles for males and 5-25 square miles for females. Home
ranges are larger in summer and fall than in winter and spring, and in an
Idaho study, were separate, and contiguous.
The smaller winter range is apparently a function of the movements of it's prey (elk and
deer). However, these ranges are not defended. Nowak
reports the Idaho study with summer ranges from 42 to 117 square miles and
winter ranges from 12 to 97 square miles. Seidensticker's Idaho study
found winter/spring versus fall/summer to be as follows: males, 48 and
117; females with kittens, 36 and 44; females without kittens, 51 and 74 (all
units are square miles). Females overlap extensively, males overlap
minimally, and males overlap those of several females. However,
these results varied in other studies. Chapman and
Feldhamer reports that, rather than a true territory that is
actively defended, lions have a land tenure system, in which home ranges are
protected by resident lions, but not transient lions. The home range consists
of a primary home area, used primarily for resting, and a much larger area
used for hunting. Transient lions are tolerated by resident lions, with no
evidence of fighting. Home
ranges are maintained more by avoidance (recognition of scratchings and
scrapes), rather than by active defense. Lions will travel 20-25 miles a day.
Cougar may take a week to
complete a circuit of it's home range.
Social Structure: Solitary,
except for 1 to 6 day (NAS says two week) breeding period. Mutual avoidance is
practiced among the lions, since in a fight, both often are the losers.
Males are more territorial than
females. Resident and transient
lifestyles are known (see home range above).
Males play no role in child rearing.
Life Cycle: Litters of two to four (6 have been recorded) are had
normally every two years (consecutive years are known in ideal conditions). The males only associate with the
females to mate, which occurs often over a 2-4 day period, and then are off again. Breeding can occur any month of the
year in southern regions, but is most common from December to March with
births peaking between April and September.
Mating, which may induce ovulation, is by the dominant male (the female
does not choose the mate).
Acknowledging ovulation is induced by copulation in cats, Forsyth
suggests, in the case of mountain lions, estrus is induced by the abundance of
food. Females are seasonally polyestrous,
with the estrus cycle lasts
approximately 23 days, with the estrus usually lasting 8 days.
Gestation period of 90 days. Youthful spottings will disappear at 12 to
14 weeks (Nowak says 6 months), about the time the young begin to hunt with the mother.
Young are weaned in three months (Forsyth says 4 to 5 weeks), and may
stay with the mother until late in the second winter. Litter mates stay together for 2-3 months after leaving
the mother. Males will disperse from 25 to 50 miles and
females 2 to 20 miles from the birthing site.
Females reach sexual maturity at two and a half to three years of age
and will normally breed every other year, except in optimal conditions. Males may not mate until at least 3 years, but regular reproductive
activity does not begin until a young animal establishes a permanent home
area. Life span seldom exceeds 12 to 15 years, with the record in
captivity reaching 22 years.
Dens/Nest: Dens in any concealed,
sheltered spot, including caves, rock crevices, under uprooted trees, or in
dense vegetation. Little, or no
nests (bedding material) are made. The
birthing site, free of feces and prey remains, is abandoned after 40 to 70
days, but is often used in subsequent years.
Tracks: Front feet, 3 ¼” x 3 ½”
(L x W); rear, 3” x 3 ¼”. Cats
(often) walk with rear feet going into front footprints (direct register).
Straddle is 8”. Stride is from 14” (slow) to 36 – 72” (fast).
The regular gait may be about 20". Four toes front and rear, no claws.
Mountain lion and domestic cats have all toes of equal size.
Scrapes, made primarily by resident males, transients, and females
without kittens, are sometimes made by kicking up piles of dirt by the hind
feet, serving as boundary markers. Such
scrapes are 6 to 18” long and 1 to 2” high.
Scat: Cat scat tends to be segmented, unlike canids.
Scat is ~1 ¼” diameter and 9” long.
Signs of scratchings to cover the scat are often visible.
Like the bobcat, urinates on “scrapes,” made of leaves and twigs,
to mark its territory. Such scrapes can be 2-3 feet wide.
Remarks:
Aka cougar, puma,
and panther (especially in Florida). This large cat has a large, long tail,
with a black dorsal side. Very secretive, these cats swim and climb trees
well. The loss of this predator, along with the wolf, has resulted in a
dramatic increase in the eastern population of deer (along with an increase in
suitable deer habitat).
They
can leap 18 feet up into a tree.
Sight
is the most acute sense and hearing is also good, but smell is thought to be
poorly developed. The
mountain lion’s eyesight is highly adapted for night vision, thus requiring
a large pupil and iris to gather light. This
high sensitivity to light require increased protection for the lion’s retina
in daylight. Hence, the pupil
contracts to a vertical slit, or “cat’s-eye”, in bright light.
It is
interesting to note that reports of black panthers are made each year despite
the fact that a black, or melanistic, panther has never been documented at any time in North America.
The only documented case is from Brazil.
(However,
Rue
reports several records of melanistic lions in Florida.)
The
last cougar shot in the Smokies, was near Fontana Village in 1920.
The last in Pennsylvania was killed in 1871, in Virginia in 1882, and
in West Virginia in 1887. The last holdout in northeastern US was in the Adirondacks,
where the last known cougar was killed in 1903.
A small population has survived from central Maine northwards into Nova
Scotia and New Brunswick (Canada),
and in Alabama and further south.
Reports
of mountain lion sightings in the east are numerous. Pennsylvania officially lists the mountain lion as
"undetermined", based on numerous sightings and the possibility of
releases from private owners and game parks.
Between
1979 and 1994, a total of 279 reports of cougars in Virginia have been
received. Of those, 124 were deemed reliable. Most reports center
around the New River Valley of Montgomery-Giles-Craig counties and the Peaks of
Otter area of Bedford and Botetourt counties. One report comes from a
veteran US Forest Service technician who spent 25 minutes watching a female
cougar with two cubs sunning themselves near Peaks of Otter in 1990. The
situation in Virginia is best summarized by Handley (1991), who stated: There
most likely are mountain lions in western Virginia, but hard evidence is
lacking. How many there are, where they are, whether they comprise an
established breeding population, and whether they represent native Felis
concolor couguar or introduced, exotic subspecies are uncertain. This
same position can be said of any state in this Appalachian study area.
The Shenandoah National Park
receives numerous cougar sightings every year (~10). Over 20 reported
sightings were received in 1997. While Park
officials will acknowledge mountain lions have been present in the
Park, they believe these are probably human releases.
(It has been reported that the embryo from a doe killed by a panther
had been removed and eaten. Coincidently, in the winter of 1997, an embryo was found
lying on top of a doe’s corpse in the Shenandoah National Park by this
author.)
Mountain lions usually open the chest or belly area of the prey and eat
the organ meats first. The do not eat the stomach or its contents, but
often roll these out of the carcass intact. What cannot be eaten at that
time will be covered with leaves, sticks and even logs.
Regarding
the Smokies, Culbertson(1977) states, “The number of lion sightings through
the years suggest that the mountain lion may never have actually been extinct
in the Great Smoky Mountains area. The
lion may have been able to maintain itself in small numbers in the more
inaccessible mountainous regions in or around the park.
The present lion population could be derived in part from this small
reservoir…It is believed that there were three to six mountain lions living
in the park in 1975, and other lions were reported to the southeast and
northeast of the park as well. “ Officials
recognize this possibility, but see more likely the likelihood that they may
be captive animals that have either escaped or been released, especially
acknowledging that Tennessee residents are legally allowed to possess captive
western mountain lions.
The
Florida panther, a distinct subspecies, is the only reproducing population of
mountain lions in the east, in southwest Florida, extending northward to the
latitude of Lake Okechobee. This
population has an estimated population of up to 50 animals.
Eight Texas cougars (Puma concolor stanleyana) were released into South Florida in 1995
by the state of Florida with the intent of increasing genetic variability.
This highly questionable action opens the question of the existence of
a pure P. concolor coryi subspecies,
and appropriateness of Endangered Species protection status.
More information on the Florida panther can be found at FLORIDA
PANTHER.
About
four humans are attacked by mountain lions each year with 14 fatalities in the United
States and Canada in the twentieth century.
Five of those people have been killed and numerous others mauled throughout the
western states in the past ten years.
Most are children or adults traveling alone. Such encounters are on the increase due to increasing cougar
populations, residential development in cougar habitat, and lack of fear of
humans resulting from a ban on hunting cougars in California.
Biologists
have “estimated” a total figure of 25,000 to 30,000 cougars in the US and
Canada. Rue suggests
15,000 in the US and another 6,000 in Canada. As of 1991, about 2,100
cougars were killed annually in the US and Canada.
BACK
TO THE TOP OF CARNIVORES
BOBCAT
(Lynx rufus) (cat; reddish)
ARTICLES
Appalachian
Region Distribution:
Throughout.
Continental Range: Most of US (with the exception of the mid-western
States - Great Lakes area) and Central America. The most widely distributed
cat in North America. Four
subspecies in the eastern US, with only one
subspecies in the
Appalachian
region.
Abundance: Common.
Population Density: .04 to 4 /
square mile, with the lower limits more common. Chapman and Feldhamer reports numerous studies that average about
0.25 per square mile, or about 1 bobcat per four square miles. Nowak
reports maximum population densities of 1 per square mile in the southeastern
US. Wilson reports a range from .1 to 7/ square mile.
Size and Molt: Head and body
average for North America is 29" for males and 26" for females (
ranging from 25 to
35 inches ), standing about 22" at the shoulder. Males are up to a
third larger than females, males average 26 pounds, ranging from 16
to 57 pounds, and females
average 20 pounds, ranging from
8 to 33 pounds.
Record size from Maine is 76 pounds.
Bobcats from VA, WV and NC are larger than more southern populations.
And, for those who are interested, the average tail length is about 6"
long! Two molts; the summer more red than the more gray winter pelage.
(Interestingly, the lynx has only one fall molt.)
Mammae: Mammals of PA says two pair. Peterson’s, Mammals of
Virginia says three pair.
Habitat: A wide variety of
terrestrial habitats including deep woods, open areas, riverine and
semi-developed residential areas. Prefers areas with heavy underbrush,
adequate prey, protection from severe weather, availability of rest areas, and
freedom from disturbance. The
importance to bobcats of rock piles or broken rocky ledges for use as dens and
mating is well documented. The
habitat of the bobcat is much broader than the lynx due to the generalized
dietary needs of the bobcat.
Active Period: Predominantly
crepuscular to nocturnal, year-round, but may be abroad at any time of the
day, especially in the winter.
Diet: Exclusively carnivorous, but,
unlike the lynx that is dependent almost exclusively on snowshoe hares for its
diet, the bobcat is quite the generalist.
Rabbits and large rodents and opossum-sized mammals are the preferred
food (weighing between 2 and 12 pounds). The second most frequent prey size
group taken comprised those larger than 12 pounds (beaver and ungulates).
Third choice will be prey less than two pounds (squirrels, rats),
followed lastly by smaller prey (mice, shrews, voles) and carrion (as a last
resort). Will also eat grouse, turkey
and other ground-nesting birds and their eggs. Will cache food (especially large prey like deer).
In winter, capable of killing deer in deep snow, or in times of limited
prey.
Home Range: Studies reveal quite a
range, from .2 to .6 square miles to 15 to 25, even 80 square miles for males,
while the female has a much smaller range (often less than half the male
range), the boundaries which are marked by urine, feces or scratchings, on
prominent objects. Home range
varies depending on prey and population density, sex, age, season and climate.
Chapman and Feldhamer reports a Minnesota study that had a male range of 24
square miles and a female range of 15 square miles. A Louisiana study
found home ranges for males to be about 2 square miles, with only 1/2 square
mile for females. Rue reports 60 square miles for males and 6 square miles for females (only one square mile for mother and
young). Winter ranges are much larger than summer range. W/H says summer
ranges are about 0.3 square mile for males; 0.15 square mile for females;
while winter ranges are 10 to 20 square miles for males with females having
much smaller home ranges.
Range overlaps are variable. Most references indicate female ranges were
almost exclusive of one another, but the ranges of males overlapped one
another, as well as those of females (Nowak, Chapman and Feldhamer , and
W/H). Wilson says same sex doesn’t overlap, but opposite sex of both overlap.
Stokes says neither male or female range overlap. Finally, Brown says males do not overlap.
Clearly, bobcats appear to be quite adaptable. Chapman and Feldhamer says resident animals
may share prime habitat sites, but transient animals – often sexually
immature animals - are almost always excluded from these areas. All
observed changes in resident home ranges were attributable to the death of a
resident. A bobcat will take a week or two to
complete a foraging circuit of its range, traveling about 2 to 7 miles a
night.
Social Structure: Solitary,
mutually avoiding others in the same range. Male
has no role in child rearing (some records of staying and helping with the
raising of the family do exist, but with some males known to kill kittens,
this help seems highly unlikely to be accepted by the females). As
mountain lions, bobcats can have either resident or transient lifestyles.
Transients appear essential to the stability of the resident populations due
to their ability to fill quickly any vacated range and won't mate until they
fill in a vacated range. Transients are usually dispersing juveniles.
Life Cycle: One
litter per year is commonly born in April or May, with an average of
two or three cubs (1-7) per litter. Two broods in a
year may occur if the first brood is lost, or in favorable situations in the deep
south. In this study area, breeding
peaks in February and March, although breeding may
occur any month of the year in the deep south. 1 1/2 year old females
may also give birth in the fall. Chapman and Feldhamer suggests three
spontaneous (versus induced) ovulations possible, occurring 44 days apart
(assuming pregnancy does not first occur), although both spontaneous and
induced ovulation may be occurring.
Males are sexually active all year. Gestation period of 62 days. Cubs are weaned in
two months and will stay with the mother until fall (normally), late winter, or even
later. Females can breed at one year, but most require two years, as do all
males. Life span is eight to twelve years, with one living 34 years in
captivity.
Den/Nest: Females make a natal den in rocky outcrops with ledges, under
logs concealed by vines, brush piles, thickets, rock ledges, hollow logs,
stumps, or in the roots of fallen trees. Bobcats do very little digging
of their own. Makes little or no nest of leaves and
grass. Otherwise, several
shelter, or auxiliary, dens throughout their home range are used. Note the "cat" smell.
Tracks: Tracks are 1 ½” to
2" diameter and round; four toes and no claws. Stride is 10 to 16"
(domestic cats have 1" tracks and average strides of 6 to 8").
Tracks are more rounded than canids, with no claw marks.
Canids are more in a direct line, while bobcats zigzag. The ball pad of the bobcat is distinct from that of the coyote in that
the anterior border is two-lobed.
Scat: Scat is similar to fox and
coyote, but more segmented, or, even in pellets. Look for scratches around scat. Bobcats may cover their feces or leave them uncovered
on unprepared or prepared sites such as a scrape.
Most uncovered feces are found around dens and well-used trails.
Scrapes are made with the hind feet in leaves on which they defecate to
mark their territory (10 to 20” by 4 to 6”).
Urination sites are commonly used throughout the bobcats’ range.
Also known to make “scratching trees”; dry, barkless snags that the
bobcat uses by standing on its hind legs and scratching with its front feet.
Remarks:
Bobcats are
slightly smaller than the lynx, with shorter legs and smaller feet. The
tip of the bobcat's tail is white with a black bar, while the lynx's tail tip
is black.
What snowshoe hare is to lynx, cottontail rabbit is to the bobcat.
However, the bobcat is much less the specialist than the lynx, both in
terms of prey and habitat.
This
medium-sized cat, half-way between a domestic cat and a mountain lion, has a
short tail, between four and six inches long.
Color variation is considerable, with melanistic bobcats identified in
Florida.
Bobcats
and lynx are allopatric (they don’t share the same habitat).
Where the bobcat has been introduced into lynx habitat, as on Cape
Breton Island, the bobcats have segregated themselves into the coastal
regions, while the lynx has taken over the higher elevations.
Bobcats
are active climbers and can often be seen foraging or resting high in trees.
It is
believed the tufted hairs on the tips of the ears aid the bobcat in hearing,
acting as a sort of antenna in catching sound impulses.
Male
bobcats have been known to breed with domestic cats, having fertile young,
with or without bobbed tails.
The US Fish and Wildlife estimates there may be as many
as one million bobcats in the US. Another study in 1981 estimated a
bobcat population of between 725,000 and 1,020,000 in the US.
During
the six seasons from 1970 to 1976, bobcat harvests in the US averaged 21,860
animals per season.
In the season of 1976-77, 72,220 bobcats were taken in the US, with an
additional 3,459 taken in Canada. The total known annual kill in the US
was approximately 92,000 in the late 1970's. (Numbers probably increased annually
until the early 80's, reflecting pelt prices which reached a peak of $300-$400
each in 1975-76.)
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