ORDER RODENTIA - Rodents  

         CHIPMUNK       WOODCHUCK    TREE SQUIRRELS  FLYING SQUIRRELS
           BEAVER                MICE                RATS            MUSKRAT
            VOLES          LEMMINGS      JUMPING MICE         PORCUPINE

 

Rodents are the largest order of mammals in the Appalachian region (as well as the world), both in species and actual numbers. In fact, 40 % of the world’s mammalian species are rodents.   The diversification of species has been a relatively recent and rapid evolutionary event, with few extinctions, causing much consternation among taxonomic botanists.

Rodents are the "gnawing" mammals. Rodents are known for their pair of large upper and lower chisel-like incisors.   Each incisor is a segment of a true circle, continuously being pushed out of the end of the jaw.  Some species have incisor growth rates of one inch per month. Unlike lagomorphs that have enamel covering the entire incisors, rodents only have hardened enamel on the anterior (front) side of the incisors.  This keeps a sharp edge on the teeth, since the relatively soft posterior (back) side of the teeth wears more quickly than the front. Also unlike lagomorphs, rodents have only one pair of upper incisors, instead of two permanent pair.   These incisors grow throughout the life of the rodent, kept in proper length by grinding of the teeth, not necessarily by gnawing plants.  Rodents lack canines, with the gap between the incisors and molars known as the diastema.  This large gap allows rodents to curl their lips backward into it while gnawing and chewing.  This behavior also permits the rodent to exclude unwanted soil and debris from its diet.  This also enables muskrats and beaver to eat underwater without inhaling water. The grinding molars, or "cheek" teeth,  are a combination of vertical layers of dentine and harder enamel, which produce peculiar ridged patterns on the crown of the teeth, useful in classification by zoologists.

Rodents have diversified to adapt to a variety of lifestyles including terrestrial (mice and voles), arboreal (squirrels), fossorial (woodchucks), semiaquatic (beavers and muskrats), and volant (flying squirrels). They range in size from a third of an ounce of the harvest mouse, to the eighty pound beaver. All are herbivores.  

With the cooling and drying out of much of North America during the Tertiary and the Eocene (40-55 million years ago), forests transformed into grasslands, with the concurrent evolution and diversification of mammals.  Grasses became the most important of all the flowering plants and became the  nutrient source base of wildlife herbivores, domestic grazing livestock, and, in fact, mankind.  As the plants provided an abundant energy source, herbivores expanded in number and evolved into the ecological niches.  The ungulates evolved in the Eocene, the grass-eating marsupials arose 25-38 million years ago, and the voles of the microtus genus were the last to emerge, about 10 million years ago.  They have rapidly evolved and diversified for the past 6 million years filling all grassland niches.  

In order for rodents to fill out the grassland niches, two adaptations were necessary. First, as a result of the abrasive silicas in the cells of grasses, teeth, easily worn down by the silicas, became ever-growing throughout the life of the rodent.  The second adaptation was the ability of the herbivores to digest the complex carbohydrates contained in the fibrous portion of grasses through fermentation in the animal's gut by microorganisms.

The success of the rodents became a problem in itself as carnivores evolved to take advantage of this abundant new food source.  In response, special reproductive adaptations evolved to enable massive birth rates within the rodent order. This includes "postpartum estrus" in mice, with females being mated within hours of birthing.

Rodents have four toes (sometimes five) in front and five toes in the rear.   

Rodents are known from fossils in North America dating back to late in the Paleocene Epoch (60 million years ago).

Worldwide, the rodent order is represented by 29 family, 468 genera and 2,052 species (Nowak's Walker's Mammals of the World).  In North American, there are 9 families,  43 genera, and 217 species (Jones' Checklist of North American Mammals).  In the eastern United States, there are about 38 species and five introduced species.

Rodents include twenty nine species in the Appalachian region within five families. These include the squirrel - which includes the groundhog - (Sciuridae), beaver (Castoridae), porcupine (Erethizontidae), mice, rat and vole (Muridae), and jumping mice (Zapodidae) families.

 

Family Sciuridae - Squirrels and Woodchucks

This family can be divided into three groups; tree squirrels, flying squirrels, and ground-dwelling squirrels (woodchucks and chipmunks). Tree squirrels are diurnal, leading solitary territorial lives, living on nuts and fruit.  The woodchuck and chipmunk are also diurnal.  Flying squirrels are nocturnal and tend to be more omnivorous.  The family name means "shade tail", alluding to the large bushy tail of the arboreal tree sciurids. Most of these family members stand on their haunches to view their surroundings. Most members of the sciurids have high birth rates to compensate for their high mortality, especially to the weasel family (R-selected strategy populations, like the lagomorphs).  Squirrels come in different sizes, habits, and habitats to maximize utilization of available resources and to minimize competition among species.  They have the largest brains relative to their body size of all small mammals and are the most intelligent of the rodents, as is reflected in their complex vocalizations and social systems.  Some are arboreal (red, gray, and fox squirrels), some are semifossorial - burrowers (prairie dogs, ground squirrels, woodchucks), and some do both (chipmunks).  Some hibernate (woodchucks), some enter deep torpor and feed occasionally on cached food supplies (chipmunks), and many are active year-round.   

Squirrels manufacture enzymes that enable them to eat the toxic amanita mushrooms.  However, like the pit viper that produces its venom and the skunk that produces its musk, the squirrels produce these enzymes at a physiological cost, thus “balancing” the benefit.  

The front foot (hand) has four toes and the rear foot  has five toes.

Worldwide, the 51 genera and 272 species of the squirrel family includes marmots, woodchucks, prairie dogs, ground squirrels, chipmunks and tree squirrels (Nowak's Walker's Mammals of the World).  They range in size from 1/3 ounce of the pygmy squirrel, to 16 1/2 pounds of the marmots.

Of 8 genera and 68 species found in North America, seven species are represented in the Appalachian region (Jones' Checklist of North American Mammals). 


EASTERN CHIPMUNK (Tamias striatus) (treasurer, or storer; striped)

Appalachian Region Distribution: Throughout.
Continental Range: Eastern US and southern Canada.  Nine subspecies are recognized in eastern US, with three in the Appalachian region.
Abundance: Common
Population Density: 12 - 24/ acre; with great annual variation.  
Size and Molt: Head and body five to six inches; 2 ½ - 4 ½ oz. Two molts.
Mammae: Four pair.
Habitat: Open deciduous forests; especially rocky areas and forest/field bushy edges.
Active Period: Diurnal, with two peaks of daily activity, with a midday slump. Inactive in extremes of winter and summer. Whether chipmunks hibernate or not depends on your source and definition. They do not develop a layer of brown fat as does a true hibernator. Instead, they go through periods of torpor of variable length (rarely more than several days at a time) and frequency, normally starting in October or early November.   Not all animals in a population will become torpid.  During these periods of torpor, studies reveal chipmunk respiration rates drop from 60 to less than 20 breaths per minute, and temperature drops from 100 to 42 - 45 degrees. Chipmunks must wake about every two weeks to eat from their caches and defecate.  Will come out in mild weather any time.  (Mammal of Virginia states chipmunks have been seen in Blacksburg, VA at 15° F and three inches of snow on the ground.)  Individuals vary on length of torpidity, and can change from one year to the next.   Additionally, those of more northern habitat tend to spend more time “hibernating” while those of the south enter a torpid state only during severe winter weather.
Diet: Nuts primarily, with a preference for hickory. Also eats fruit, mushrooms, some invertebrates, annelids and arthropods (snails, worms, cicadas, and other insects). Chipmunks spend a lot of time caching food in their burrow, especially during fall. The food is used during waking time of winter's hibernation. Like the gray squirrel, the chipmunk disperses its food caches to deal with theft.  It has a primary storage site in its burrow and numerous smaller scatter hoards well hid throughout its territory.  As other chipmunks raid the primary storage site, the owner will refill it from the scatter sites.  If no thievery occurs, the scatter hoards often go unused, being left to rot or sprout. Carries food in its cheek pouches. One chipmunk was found to be carrying 70 sunflower seeds in its cheek pouches.  Another; 32 beechnuts.
Home Range: ½ - 2 acres, overlapping with others, with a smaller defended territory. Ranges may shift annually for food, winter protection, or for finding mates. Males have larger ranges than females. Within the home range is a protected territory, about 45 feet radius from the burrow opening.   Juveniles typically establish their own burrow systems near their birthplaces.    A PA study found a home range of .27 acre, with a 0.05 acre range when seeds were ripe.  An Adirondacks report was 0.5 - 1 acre.
Social Structure: Solitary and territorial mammals, although known to overwinter in small family groups. While ranges overlap, adults will strongly defend its smaller territory in order to protect it’s food caches and during breeding time.   There are no lasting pair bonds.
Life Cycle: Under favorable conditions, two seasonal breeding periods occur; with birthing in April and July or August, with usually four to five per litter. The second birthing period often consists of last years' young that failed to breed in the spring, although a number of chipmunks breed in both spring and summer, unusual in hibernators. This second birthing period does not appear in northern populations.  Females are in estrus for 3 to 10 days.  Gestation period of 31 days, weaned at 5 to 7 weeks, at which time they first leave the nest. At about 8 weeks, the female refuses to let the young re-enter the burrow and the young are on their own. This dispersal may be abrupt or take a week or two. At this time, adults will make continuous "chirps" near their burrows, perhaps advertising their own territories. Chipmunks can be sexually mature at approximately three months.  However, most individuals do not breed for the first time until they are one year old.  Life span of two to three years, although records of up to 13 years in captivity have been recorded .
Dens/Nest: Burrows fall into two categories.  They can be simple with one or two tunnels used for a hideaway or for food storage, or quite extensive with over 100 feet of tunnels (average is about 12 feet in length) used for nesting and storage.  Extensive tunnel systems include a ten inch diameter nest chamber and separate chambers for food caches approximately 3 feet underground. Surface opening is often straight down and 1 1/2 - 2 inches diameter. Openings are often plugged with soil each night and during the winter. Two side tunnels and openings may exist, but are often plugged and not used. May occupy the same burrow system for life. Burrows are not shared except briefly by the mother and young. Tree cavities are occasionally used.
Tracks: Four front and five hind toes approximately ½ to 5/8" wide and a long, depending on depth of imprint. Not common in winter since often will be hibernating. Straddle is 2 - 3". Holes of 2 inch diameter leading straight down with no trace of excavated soil is the diagnostic home of the chipmunk.
Scat: Small piles of four to six rice-sized droppings.

Remarks: Runs with bushy tail straight up. Perhaps best identified by it’s sharp chuck-chuck call in the woods as hikers pass. Well-developed cheek pouches stores have been known to hold up to 32 beechnuts or 70 sunflower seeds. Food caches also are kept throughout their range. Has been reported to overwinter with rattlesnakes, purportedly sharing the snake’s warmth. Understandably, the chipmunk enters the den after the snakes have become torpid, and exit in the early spring, before the snakes lose their lethargy.  However, chipmunks are a common prey of rattlesnakes.  The name chipmunk is of native Indian origin and probably relates to its chipping call.

Chipmunks from western Maryland are paler in color, and those from the Carolinas brighter than those from other areas.  The darkest individuals are found in the southern mountains, SW VA, Kentucky and Tennessee.   Both albinos and melanistic individuals are known.

There are twenty four species of chipmunks in North America (Nowak's Walker's Mammals of the World - the Checklist of North American Mammals lists 22 species).  There is one eastern species and 23 (or 21) western species.  The 1994 edition of Nowak's states the smaller western species and eastern species were formerly placed in one genus; Tamias, but recent evidence had caused the western species to be split into a separate genus, Eutamias.  Thus, at that time, the eastern chipmunk was the only species in the genus Tamias."  However, the 1999 edition of Nowak has the above two genera combined again in the same genus; Tamias.  It goes further to say, "There is general agreement that the issue is not settled and further investigation is needed on chipmunk systematics."  

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WOODCHUCK (Marmota monax) (marmot; solitary)

Appalachian Region Distribution: Throughout.
Continental Range: Most of Canada and eastern US.  Four recognized subspecies, with one in the study area.
Abundance: Common; in fact, more common than in pre-Colombian times.
Population Density: W/H says 1 per 11 acres, occasionally up to 1 per 2 acres. Nowak reports a Wisconsin average of 1/125 acres.  Other sources say 2-6/acres.    Populations tend to vary greatly year to year.  
Size and Molt: Head and body 12-20 inches; 5 - 12 pounds. Hibernation results in the loss of about 30% of fall body weight.  However, weight loss immediately after emergence from hibernation was much greater, with energy derived from remaining stored fat reserves.  Males tend to be slightly larger than females. One summer molt, taking 3 and ½ weeks, occurring from late May into September.
Mammae: Four pair. 
Habitat: Prefers open fields, but found in mature woods, pastures and hayfields.
Active Period: Primarily diurnal to crepuscular (morning and evening, like deer). Only spends one to three hours above ground each day during the summer. True hibernators, entering their dens in the first week of November  and emerging in early February (sometimes requiring help for Feb 2).  Populations further to the north may hibernate for up to four months, while more southern populations may only hibernate for six to eight weeks or not at all.  Winter activity has been documented, but is atypical.  Older and fatter woodchucks enter their hibernacula first and emerge first.
Diet: Herbivorous grazers.  Seasonal herbs and fruits, but known to taste grasshoppers, beetles and snails. Does not cache food.
Home Range: 2 - 5 acres.  Woodchucks exhibit little territoriality, except in the direct vicinity of their burrows.  Home range may shift from winter to summer den sites with corresponding shifts in home  range.  Same sexes do not generally overlap, but males may overlap 1-3 females.  Female ranges are generally smaller than males in the spring, but may become larger than males after young are born before contracting again in the fall.  
Social Structure: Solitary, but may live in small family groups with a male dominance hierarchy. Woodchucks are not territorial, relying on a dominance/submission hierarchy to establish avoidance of dominants by submissives where home ranges overlap.  Burrows are occupied by a single male, a mother and her young, or occasionally, a male and a female.  Contrary to other marmots, the woodchuck is fairly aggressive.  This is a function of the length of the growing season.  The shorter growing season of the western marmots (60 days) requires more time together to assure ample breeding (the Olympic marmot shares its burrow with an adult male, two adult females and offspring from the previous two litters).  The eastern woodchuck can afford to be more picky (150 day growing season in PA).
Life Cycle: Mating shortly after spring emergence (late February  to early April), one litter of four to five is produced in April to mid-May.  Gestation period of 32 days. Weaned in six weeks and on their own (chased off by mommy dearest) at two months of age (July).  By fall, the young have established their own burrows.  Occasional young females will overwinter with the mother, like other ground squirrels.  10 to 25 percent may reproduce in the subsequent spring at one year of age.  Most will mate in their second or, more commonly, third year. Life span of four to six years. (Nowak reports 13-15 years).
Den/Nest: Will normally have both a summer and winter den. The winter den (with normally only one opening) is often situated in brushy or gently sloping wooded areas, whereas the summer den (with several openings) is in open, flat fields. Occasionally, the winter den is used year round and by succeeding generations. The burrow system includes nest chambers, and/or a hibernaculum chamber (both about 15" wide and 10" high, lined with leaves and grass), and a latrine chamber.  The summer system has a number of surface openings, easily identified by the excavated soil and a number of nests. In addition to the main opening, there may be up to five more or less obvious openings for emergency entrance or exit needs.  At least one of these hidden entrances will be a “plunge hole”; having a two foot drop from the surface.  Burrows may be four to five feet deep (reportedly up to 16 feet deep) and 25 to 50 feet long.  Other mammals will use woodchuck burrows (skunks, foxes, opossums, raccoons, rabbits, mice, and others).  A woodchuck burrow can be distinguished from others by the fresh pile of soil at the main entrance, since woodchucks clean out their burrows several times a week.  Unlike foxes, woodchucks will not defecate outside the entrance.  Rather, they use separate chambers in the burrow.
Tracks: Four toes on front feet, 1 ¾" by 2" long, and five hind toes, the front a little longer than the rear.  Running gait shows four feet tracks within 12" and 12" between sets of prints.
Scat: Quite variable, depending on diet.  Often 2 1/2" long by 1/2" wide.  Can be longer strings (if not separated) or more loose piles.  Fecal pellets are often deposited in a specific fecal chamber underground or buried in the loose soil excavated outside of the burrow.  This burying behavior is unknown in other squirrels.

Remarks: The common name comes from the Cree Indian word, wuchak.  The largest member of the squirrel family, with a flattened, bushy tail. Also, the most widely distributed and best known of all the marmots.  The only representative of a genus of circumpolar distribution. An accomplished climber and swimmer. True hibernators, with the oldest (and fattest) entering the burrow first (late October). In Autumn, after gaining 30% of it’s summer weight (mostly in the form of a half-inch layer of brown fat stored over much of the body, especially the back and shoulders), the ground hog will line it’s hibernaculum with grass and leaves and then plug the entrances (to maintain constant temperatures and to keep out curious visitors) before curling into a ball. During hibernation, heart rate drops from 100 to four beats per minute (W/H says 100 to 15), respiration rate drops to one breath per three or four minutes, and the body temperature drops from 98 to about 40 degrees (W/H says 96 to 47). Males usually exit a few days earlier than females in early March (similar to the hibernating jumping mice) (W/H says one month earlier). This allows males to compete for good home range and dominance over other males.  The period of hibernation is about three to four months, with each 10 miles northward adding one day of hibernation; given similar elevation.  Due to the shortened northern growing season, the emergence is much more precise than in the southern range, thus enabling the well-known "groundhogs day" of Punxsutawney PA on Feb 2.  In an eight-year period, the PA emergence date fell between January 29 and February 8, regardless of the weather.  They will awaken occasionally throughout the winter (about every two weeks) to defecate. This may occur in special chambers below ground or, less frequently, on the surface. They will emerge having lost approximately one half their fall weight (W/H says 20 to 37%).  Ground hogs have been observed every month of the year, even occasionally with snow on the ground and temperatures in the 20’s.

Melanistic (black) or erythristic (reddish-cinnamon) groundhogs are not uncommon. Albinos are uncommon. Is known to climb trees for fruit and is a good swimmer. It’s loud, shrill whistle gives it the common name "whistle pig" (call is made with vocal chords; thus, not truly a whistle).  At the beginning of European man's introduction, woodchucks were scarce.  As a result of human disturbances, the range and population of ground hogs have increased over the last 200 years.  

In Kentucky, between 1964 and 1971, some 267,500 ground hogs were taken each year!

There are six other North American species in the genus Marmota, all located in the west, called marmots. 

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EASTERN GRAY SQUIRREL (Sciurus carolinensis) (shadow tail; belonging to Carolina)

ARTICLES

Appalachian Region Distribution: Throughout.
Continental Range: East of the Great Plains and south of the Great Lakes. Basically, their range correlates with the eastern hardwood forests.   Five subspecies recognized in eastern US, with only one in the study area. 
Abundance: Common at lower elevations; rare at higher elevations. Populations reflect "mast" years (acorn supply).   Much higher numbers were found when the native American chestnut tree was common.                     
Population Density: Highly variable, with highest populations in late August and September.  Chapman and Feldhamer report four WVA state forest densities over a six year period ranging from 0.44-1.0, 0.24-0.84, 0.2-0.44, and 0.32-1.4 per acre.  Our friend, Dr. Vagn Flyger of Silver Spring, MD, found a range in his suburban yard backing up to the Northwest Branch in Quaint Acres from 0.8-4.0 per acre over a three year period.   2-20/acre in some studies, others report 0.1-6/acre; max up to 20 / acre (public park densities can exceed 50 per acre).  
Size and Molt: Head and body is 9 to11 inches; ¾ - 1 ¾ poundsSexes are alike in size and color.  Two molts; paler winter pelage, although the tail molts only once in mid summer.  Northern individuals are larger than southern populations.  
Mammae: Four pair.
Habitat: Mature oak and hickory hardwood forests.  Land use may be highest in forested river bottomlands, river valleys and swamp hardwoods.  Extremely adaptable, they are found anywhere, except spruce/fir forests, where red squirrels dominate.  Gray squirrels tend to prefer more dense woods than fox squirrels.  The more large trees an area has, the more gray squirrels will inhabit the area (larger cavities and more food).
Active Period: Diurnal in winter to crepuscular in summer, non-hibernating, primarily arboreal mammals.  Active year-round, but will will remain in their nests in very cold or stormy weather until food forces them out.  W/H states that females are more active in spring and summer, with males being more active in autumn and winter.  Most active in September and early October, burying acorns (this is also the peak time for their arboreal activity).  Additionally, spring born (and some adult) fox and gray squirrels frequently move to new locations at this time.  This dispersal period is also referred to as the “fall reshuffle”, with movement of 6 or more miles.  As noted in the remarks below, this fall reshuffle, in conjunction with a failed hard mast season, can result in massive fall migrations, more appropriately called movements.
Diet: Nuts are the mainstay, with buds, flowers, and roots in spring; maple samaras, fruits, berries, mushrooms, and insects in the summer; nuts and fungi in fall and winter (specifically oak and hickory nuts and maple samaras). They usually feed on just one food at a time, changing the item as additional sources come along.  They are known to eat bark of dead trees for the fungal mycelia within.  Shedd even notes gray squirrels are known to eat bird eggs and frogs.  In February and March, they chew twigs of maples, oaks and pine. Winter food storages, or caches, consists of each acorn buried separately, decreasing the risk of losing an entire stash.  Adults obtain minerals from bones, antlers and turtle shells.  See Articles above for more information.
Home Range: Most studies indicate one to four acres, up to ten acres (varies with food availability), larger for males than females.  Chapman and Feldhammer report 2 acres for males and 1.25 acres for females in a Maryland study (Flyger).  Nowak reports 1.3 acres for males and 1 acre for females in a Virginia study.  Male home range will overlap that of several females.  Overlaps other squirrel home range.  Range of gray squirrels are smaller than the fox squirrel.  Basically, their home range focuses on (and around) one nest tree, shifting as  food sources become available.
Social Structure: Usually solitary, shy and non-aggressive.    During the mating season, males will be territorial and exhibit antagonism toward one another.  Males are polygamous.  The same applies to females on a nest.  The male provides no parental care.  Mammals of Virginia say gray squirrels are gregarious and often congregate in considerable numbers, while W/H says they  are not social, only gathering in winter denning situations..   Chapman and Feldhamer says both fox and gray are relatively nonaggressive toward either their own species or the other species, but may share dens with a number of individuals of their own species (Shedd says only males and juveniles will den together in winter, with females – probably pregnant - being cantankerous and denning by themselves).  Wilson says at night and during bad weather, as many as seven or eight squirrels may occupy a communal den, where they will groom each other and conserve heat during cold winter nights.  Among squirrels with overlapping home range, especially at high densities, there is an established dominance hierarchy, with the oldest (male or female) normally assuming dominance (W/H says males over females, adults over juveniles, and residents over immigrants).  Dominance (i.e., aggression) appears at mating time, food concentrations (including bird feeders), and at den trees. 
Life Cycle: Normally two litters of about three (1-9) per litter per year (parturition about March and August).  Forsyth says only 20 to 40% have two litters.  Gestation period of 45 days, weaned in two months; about the same time they first leave the nest.  Breeding can begin as early as December.  Males play no role in child-rearing.  The spring brood stays with the mother until late summer, and the second brood will often stay with the mother over winter. Young make leaf nests at about 18 weeks of age.  Young breed the next year (may only have one litter).  Life span has been up to 15 years, although 6 years is more the maximum. Wilson says more like one year for the average.  One captured animal lived for 23 years.
Dens/Nest: Winter and summer nests are made.  Will make winter nests in tree cavities and summer leaf nests in branches (occasionally a winter leaf nest is maintained).  A favored den tree may be used for many years, but an animal always has several other nests where it can escape enemies.  The tree cavity must be 12 inches deep and have an opening at least 3 inches in diameter.  Often, several leaf nests (called dreys) are built around different food sources. Gray squirrels average 1 1/2 to 2 leaf nests per squirrel. The leafy nest is composed of leaves and twigs forming a water-resistant form lined on the inside with moss, grass, and shredded bark. The main entrance is positioned to face the main tree trunk.  The winter nest is high off the ground in a tree hollow, lined with vegetation.  Normally, the first brood is had in the tree cavity with the second brood in a leaf nest.
Tracks: Has five toes on hind feet (2 5/8" l x 1 1/4" w) and four on the front feet ( 2" l x 3/8" w).  Straddle is 4 to 5". Running stride of 16 - 36".  Front and rear tracks are often lined like a square, so it can give the appearance of two question marks (!!), with the front tracks behind the rear tracks (or somewhat behind and between the rear tracks) .
Scat: Pea-sized droppings (1/4 – 3/8” x 3/16”).

Remarks: Can be blonde, black (melanistic), erythristic (reddish), or albinos (Olney, IL is famous for its protected albinos - Trenton, NJ and Greenwood, SC also have albino populations). Black squirrels are more common in the northern portions of their range.  Gray squirrels from MD and the western parts of VA and NC are slightly darker and larger than those from eastern VA and most of the Carolinas. It is common for one of the color variants to be dominant in an urban setting, since the predatory natural selection (culling out) of these colored aberrants does not exist.

Melanistic gray squirrels of the Washington DC area owe their existence to two shipments of black squirrels from Ontario being released in the National Zoological Park in 1906.  It appears that the dark pelage gives them an advantage over the gray winter coats of the normal squirrels in winter through energy savings due to the additional absorbed solar heat (lower heat loss and lower basal metabolic rates).

Formerly known to make massive movements in search of food.  Ernest Thompson Seton estimated one mass movement at more than one billion individuals in 1920.   Such migrations are necessitated by local high populations and erratic annual acorn mast crops.  A more recent mass movements on a reduced scale was reported in October of 1968 in the southern Appalachians of TN, GE and NC.  This followed a mast crop the previous year, resulting in  an abundance of young squirrels.  Unfortunately, 1968 was a poor mast year, resulting in a major food shortage.   Such a phenomenon is incorrectly called a migration, when it actually is nothing more than a big fall reshuffle.

Caching of seeds and nuts ensure tree generation. Nuts are buried separately, about 1/4" to an inch deep and are recovered by any squirrel that may smell them (one study found 85% of buried nuts were found over the winter). Nuts buried by scientists were recovered at the same rate as nuts buried by the squirrels, indicating that memory is not involved in nut recovery.  The nuts can be smelled when buried under a foot of snow.  A thicker pelage and layer of fat help insulate the squirrel in winter. While fox squirrels and gray squirrels inhabit similar habitats and share common foods, they are rarely found in the same area (mutually exclusive, or allopatric) and do not interbreed. Fox squirrels prefer the more open woods, the gray squirrels in the more dense woods. When 10% of the land is wooded, both species seem to be equally abundant.  When 70% of the land is wooded, fox squirrels are absent.  Gray squirrels are a major prey species of timber rattlesnakes. In the late summer, swellings under the skin are signs of the developing larvae of the parasitic botfly, which emerges in the fall. They do not seriously endanger the squirrel. 

Due to the extraordinary amount of tannins in their systems afforded the gray and fox squirrels by their acorn digestion, they are unusual in rarely having either tapeworms or roundworms, which is a deadly poison to these parasites.  

Much more abundant a century ago.  Gypsy moth defoliation and subsequent loss of acorns in the 1980's practically wiped out squirrel populations in southern PA.  Important game species with 40 million "harvested" each year in the US.  In Kentucky, an average of 1,309,000 gray and fox squirrels were taken annually from 1964 to 1971.

There are seven species of the genus Sciurus in North America.

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EASTERN FOX SQUIRREL (Sciurus niger) (shadow tail; dark)

Appalachian Region Distribution: Throughout.  
Continental Range: East of the Great Plains and from PA south.  The range extends slightly farther west than that of the gray squirrel but not as far northward.  W/H says to the west of a line from Harrisburg PA, Harpers Ferry WV, Roanoke VA, and along the Blue Ridge to the Smokies, with a disjunct subspecies found on the eastern shore, although other sources show  the fox squirrel ranging throughout all SE US.  However, declining populations are found in the piedmont and coastal plains regions of both Virginia and North Carolina.  Eight subspecies recognized in the eastern US, with two subspecies found in the study area.. (The well-known federally-designated endangered species, the Delmarva fox squirrel; Sciurus niger cinereus, is one of these eight subspecies.  It is only found on the Delmarva peninsula of Virginia and Maryland.)
Abundance: Uncommon in central PA and the piedmont and mainland coastal plain of VA and NC, common to the west of these locations, but with declining numbers.  Due to the decrease in the open, mature forest habitat in the east preferred by fox squirrels, their numbers are declining and often confined to small and shrinking localities.
Population Density: Highly variable.  Reported densities of 0.4 - 2/acre, up to nearly 10 per acre.  Weigl, working with piedmont and coastal plain populations in North Carolina, found densities averaging 0.002/acre.  
Size and Molt: Head and body 10 to 15 inches; 1 ¼ - 3 pounds.  (Weigl's NC piedmont and coastal plain populations averaged 2.2 lbs.)  Sexes are alike in size and color.  Largest tree squirrel in the Western Hemisphere.   Chapman and Feldhamer says two molts, with one tail molt.  Nowak says there are two molts per year in some,  perhaps all, species (of the scuirus genus), but the tail fur is shed only once yearly.  W/H, PA Mammals, says one molt in late spring.  Twice the size of gray squirrels.
Mammae: Four pair.
Habitat: Fox squirrels prefer higher ground and larger trees than gray squirrels.  Open hardwood forests and pine woods where occasional fires promote grassy surface growth are ideal. Will not be found in the closed forests of the gray squirrel.
Active Period: Crepuscular in summer, diurnal in winter; non-hibernating, they start foraging later in the morning than gray squirrels. Tends to aestivate (summer dormancy) in summer if hot.  Most active in summer in light rain or just after rains (cooler temperatures, nuts and fungi are easier to smell, and the ground is easier to dig).  Most active in September and early October, burying acorns.  Additionally, fox and gray squirrels frequently move to new locations at this time.  This dispersal period is also referred to as the “fall reshuffle”, with movement of over 6 or more miles.  However, mass movements by fox squirrels have never been as massive as gray squirrels.
Diet: No apparent difference is observed between the gray and fox squirrels.  Preference is for hickory and oak acorns.  Pine seeds from cones; green or mature and the cambium tree layer are preferred in some habitats. Also buds and berries, fungi, insects, bird eggs, and corn.  Nuts and seeds are buried individually or two or three together like gray squirrels, versus the caching done by red squirrels.  Early summer may be the hardest time for fox squirrels to find food, especially in pine forests.  The buds, flowers and young fruits of tulip trees are heavily foraged when available.  Studies on recovery of cached acorns reveal tremendous range from 33% to 99%.  Succulent vegetation will normally satisfy their moisture requirements. Water is utilized if present, but the lack of it is not a limiting factor.
Home Range: Varies by densities, food supplies, and habitat quality.  7 - 24 acres and greater are commonly reported.  Weigl's NC piedmont and coastal plains populations had home ranges estimates of 66 and 42 acres, or 107 and 62 acres, respectively for males and females.  A study of a Florida population revealed a home range of 106 and 41 acres for males and females.  This is larger than the gray squirrel, not just due to size, but also the relative paucity of food in the preferred more open woods habitat.  Home range may overlap.
Social Structure: Solitary, except occasionally to feed in common areas and share winter dens among family members.
Life Cycle: Similar to gray squirrels (but breeds slightly earlier), with two litters (from two year olds) with an average of two or three (1-6) per litter per year. (Weigl's NC piedmont and coastal plain populations revealed no evidence of two litters per year.)  If  a female produces 2 litters per year, they may produce none the next year if food conditions are bad.  Birthing usually occurs in  March and again in July, although pregnant females have been found every month of the year.  Weaned, able to eat solid food in eight weeks, and soon thereafter are independent.  Gestation of 44 days.  Sexual maturity in one year (first year females usually having only one brood).  Will disperse a distance of 9 miles or more from their birthing site.  Life span up to 12 years.
Dens/Nest: Prefers hollows in trees for winter and natal nests, but will make large leaf nests in summer (and winter if tree cavities are scarce). Cavity openings are 3 inches wide with a hollow of six inches wide by sixteen inches deep. Outside leaf nests vary greatly, averaging 20 inches in diameter. Like gray squirrels, the opening faces the trunk. Winter nests have an outer layer of twigs with leaves attached, a series of inner layers of damp leaves pressed together, with a lining of shredded bark and leaf fragments.  A leaf nest may be used for several years.  Fox squirrels average about three to six active leaf nests per individual (one study reported in Nowak found an average of nine nests were used per year).  Platforms, made just for sitting, are sometimes made.
Tracks: Four-toed front feet are 1 and 1/2" and five-toed rear feet are 2" in length.  While running/hopping, the front foot prints are parallel and behind the rear feet.  Straddle is 4 1/2" with 2' stride.  Food debris is often found scattered about the base of a tree used as a feeding perch by fox squirrels.  
Scat: Pea-sized droppings.

Remarks: Fox squirrels get their common name from their fox-like tails.  Species name comes from southern subspecies, which is much darker than other regional populations.   

The populations of the Appalachians and to the west differ from the eastern populations in being smaller (~2 lbs) and more consistently reddish in color.  The eastern populations of the piedmont and coastal plains averaged more like 3 pounds in size and were quite variable in coloration, being silver, gray, black and gold, often with black masks and with distinct white marking on the nose, ears, and feet.  Additionally, western populations inhabited deciduous forests while the eastern populations occupied mature pine-oak woodlands.  Weigl and others suggest that the southeastern and western fox squirrel populations evolved in isolation in separate refugia during the Pleistocene, eventually colonizing different regions to the north and subsequently establishing variable zones of overlap and interbreeding.

Fox squirrels have the widest range of colors of any other mammal.  Fox squirrels can be found in several dorsal (back) color morphs (subspecies); brown, brownish orange, gray-black, blackish brown, steel gray, or all black (color variations tend to match local habitat - yellow midwestern squirrels blend with the yellows of the hickories in fall, black of southeastern squirrels match periodic burning of the pine forests, etc.- its just someones' thought). Along the coastal area of Virginia and Delaware (S. niger cinereus) the population is colored steel gray with no tawny. The ventral (belly) can also vary from creamy yellow to rusty orange to black.  Fox squirrels have a darker head (than gray squirrels), some white on the muzzle and white on the back of the ears, and a larger, more fluffy tail than the gray squirrel.

More terrestrial than gray squirrels (less agile in trees than gray squirrels).  Fox squirrels spend more time foraging and running about on the ground than do gray squirrels and will more often run on the ground between trees while grays will jump from one tree branch to another tree branch.  Wilson says fox squirrels are more “easy going”, getting up later in the morning and turning in earlier in the evening.  Fox squirrels have home ranges of up to ten times the size of grays, due to the more open (poorer food supply) habitat.

Fox squirrel bones are pink (due to the accumulation of porphyrin compounds); gray squirrel bones are white. Of the three tree squirrels, the fox is the quietest, the gray more vocal, the red squirrel, the most vocal. Mass movements, well-documented among gray squirrels, are not common, nor as large, among the fox squirrels.

Due to the extraordinary amount of tannins in their systems afforded the gray and fox squirrels by their acorn digestion, which is a deadly poison to tapeworms or roundworms, they are unusual in rarely having either of these parasites.

An account by Seton (1953) states; Arlington Cemetery had always been a haven of fox-squirrels.  About 20 years ago, they had increased to surprising numbers.  Then one day, they seemed to be possessed of a migration craze; they all set out eastward.  At once, they were met by the broad Potomac; but plunged in, swimming away toward Analostan Island (Roosevelt Island), the nearest wooded tract.  Here many of them stayed; but many moved on, and were lost sight of.  They still frequent Arlington Cemetery.

Approximately 18 Fox-squirrels were released in the National Zoological Park from 1899 to 1916 from various states across the country (see remarks for gray squirrels above).  

When Audubon and Bachman were conducting their research for the Quadrapeds of North America, they noted that in South Carolina the fox squirrel "takes possession of the deserted hole of the ivory-billed woodpecker."

In Kentucky, an average of 1,309,000 gray and fox squirrels were taken annually from 1964 to 1971.

There are five species of the genus Sciurus in North America.

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RED SQUIRREL (Tamiasciurus hudsonicus) (steward, shade tail; the Hudson Bay)

Appalachian Region Distribution: Throughout.
Continental Range: A boreal species of the north across Canada, south along the Rockies to southern Arizona and New Mexico, and down the Appalachians to Smokies.  Five subspecies recognized in eastern US, with two found in the study area.  In fact, one of the widest distributions of any North American squirrel.
Abundance: Common, especially in conifer forests.
Population Density: 1-3 / acre. W/H says up to18 per acre with great seasonal variability.  Wilson notes up to 17 – 20 per acre is possible in good habitat.  Nowak reports from 2 - 11 per acre.  Population densities reach a high every three to four years in the Adirondacks of New York.
Size and Molt: Head and body 7 to 9 inches; 5 to 9 oz.  No differences in size or color by sex.  Two molts, although, the tail only molts once in the middle of summer.  
Mammae: Four pair.
Habitat: Highly arboreal.  Apparently, it originated in coniferous forests, but now is found also in mixed hardwood forests and swamps of higher elevations.  In southern limits of its range (southern Appalachians), the red squirrel is found in the same areas as gray and fox squirrels, with resultant competition for food and den sites.
Active Period: Diurnal in winter, crepuscular in summer, spending much time on the ground as well as arboreally; year-around.  Red squirrels do not hibernate, but may spend several days in their dens during inclement winter weather. 
Diet: Quite diverse diet (more omnivorous than the gray squirrel).  Due to high metabolism, a high energy content diet is required.  Some brown fat is present in winter.  Most of the energy is derived from the hemlock, pine and other conifer cones, which are stored in mass food caches ("middens") if not eaten on the spot.  Also acorns, hickory and beechnuts, tulip tree and sycamore seeds, when seasonally available, buds, twigs, occasional insects and mushrooms (including the very poisonous amanita; aka, destroying angel or fly agaric).  In the Smokies, fruits of the cucumber magnolia, mountain holly, silverbell, beech, buckeye, serviceberry, black walnut, American chestnut, and blackberry; seeds of mountain maples, hemlock, and pines; cones of fir and spruce; mushrooms; the buds of the rosebay rhododendron and the buckeye and roadside garbage cans are eaten.  Fungi are cut and placed in trees to dry for later winter eating, or later cached in middens.  Terminal evergreen buds are a main stay in winter diets.  Have been known to eat young birds and bird eggs.  Unlike the single nut burial philosophy of the gray and fox squirrels, the red squirrel goes for middens, used for winter food, which is vigorously defended. These middens (made up primarily of pine cones) may grow over the years to amass several bushels of nuts. Red squirrels can afford to make this middens where they only have other red squirrels to defend against.  However, in regions cohabited with gray squirrels, red squirrels must scatter their hordes, since gray squirrels are not intimidated by red squirrels’ threats.  Hole eaten into nut is irregular in shape.  They have favorite feeding sites, as opposed to gray squirrels, that pretty much eat their acorns where they find them.  The size of this debris pile is measured in bushels and varies with conifer species, seeds, proportion of diet, forest age, squirrel population and the feeding place, but can be up to 20 feet by 12 feet and 3 feet deep.  Red squirrels are also known to "tap" maple trees for sap. 
Home Range:  2 - 5 acres, with no overlap of range (unlike gray squirrels), but only 0.5 to 3 acres defended in the area of the nest and prime feeding areas.  In high quality habitat, red squirrels have been observed to be non-territorial.  
Social Structure: Solitary. Very territorial and aggressive in protecting their core home range (1/2 to 2 acres), especially in late summer when juveniles are dispersing.  Females allow males into their territories in late winter for mating.  Not known for communal denning in winter like gray squirrels. 
Life Cycle:  One or two litters per year (April - May) with an average of five or six (1-7) per litter. Females are receptive for only one day, at which time, she allows males to enter her territory.  Gestation period of 35 days.  A second litter is had in August in good seasons. Weaning at 9 - 11 weeks of age (W/H says 6 to 7 weeks, Novak says 7 - 8 weeks). (PA mammals says weaning occurs after the female makes a nest on the periphery of her range for her young. W/H says the female is known to occasionally leave the area to the young, who then subdivide it.)  Spring young disperse at around 18 weeks (September).   Second brood overwinters with the mother. Young are sexually mature the following season.  Life span two or three years common, with ten years known in captivity.  Only 5% of a cohort live beyond five years.
Dens/Nest: A winter and summer nest is common.  Tree cavities are preferred for winter nests, while leaf nests (~15 feet high) in summer are common (about the size of a basketball, often made of grapevine bark, while gray squirrel nests are larger and coarser), especially in conifer woods, where cavities are less numerous.  Will also build on abandoned bird nests or make use of underground dens.  Often, a second winter nest is made in the form of a weather-tight structure located in the densest foliage of a tree.  Can tunnel and make nests in the ground under rocks or stumps in the winter. Burrow holes are 2 ½ to 3 inches in diameter, often with cone remains near the entrance.
Tracks: Four front toes (1/2" l x 3/8" w) and five rear toes (7/8" l x 5/8"w).  Straddle is 3 to 4".  Running stride is 9 - 30".  In winter, makes extensive runways through the snow. 
Scat: Small, 1/4" - 1/2" elongated droppings.

Remarks: Known in WV as the "fairy diddle".  A northern species, the red squirrel is smaller than the gray squirrel, with somewhat different summer and winter pelages. In summer, a lateral black stripe separates the dorsal brown from the white ventral fur. In the winter, although the black stripe disappears, the back and tail is rusty red and tufts of hair appear on the ears. Red squirrels are distinctly darker on the head and sides in the spruce and fir forests of the higher southern Allegheny Mountains.  Both albinism and melanism is known among red squirrels.  Very vocal and active; usually heard before seen. Smaller than the gray and fox squirrels. Vocally protects it’s territory, many hunters have had their hiding place announced by the red squirrel.  Noted for its food caches, which may accumulate in size over several years, usually located in hollow trees. The seed caches (middens) are favorite sources of high quality seed used by foresters, which are cleaned and used in nursery propagation.  

Hickory nuts eaten by red squirrels will have a ragged hole opening.  Flying squirrels have smooth edges of the opening, while white-footed and deer mice will have several openings.  Gray and fox squirrels crush the nut.

The western Douglas squirrel is the only other species of this genus in North America.  Both species are known as pine squirrel, mountain boomer, chickaree, or fairydiddle.

Several million red squirrels are trapped each year for the fur trade.  

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NORTHERN FLYING SQUIRREL (Glaucomys sabrinus) (gray, mouse; Severn River)

Appalachian Region Distribution: High elevations (> 2,680') of the Appalachian Mtns. as far south as the Smokies. Can be found continuously from Maine to central PA.  South of central PA, only two disjunct relic populations exists.  Both, by their isolation, are recognized as subspecies and designated as Federally listed Endangered Species.  In six eastern WV counties (Greenbrier, Pendleton, Pocahontas, Randolph, Tucker and Webster) and Highland County, VA, the subspecies Glaucomys sabrinus fuscus was first described in 1936.  The type locality is Mill Point, Cranberry River, Pocahontas County.  The second subspecies, Glaucomys sabrinus coloratus, first described in 1953, is found in SW Virginia near Mount Rogers, VA (Whitetop Mountain) and along the Appalachian Mountains of the North Carolina/Tennessee border through the Smokies as far south as Georgia.   Populations identified for study by Weigl included Roan Mountain, Bald Knob Ridge, Grandfather Mountain, the Black Mountains (including Craggy Mountains), and the Great Smoky Mountains, among others.  For the first time since 1958, three northern flying squirrels were found in the Smokies in 1987 on Clingman's Dome. The type locality is Bald Knob, 5,000 feet south of the summit, Mt. Mitchell, NC.
Continental Range: Throughout Canada, extending south along the Rockies and the Appalachians.  Four subspecies recognized in eastern US, with the two Endangered Species mentioned above and a third found in PA making up the population of the Appalachian region. 
Abundance: Becoming rare - listed federally as Endangered in VA, NC and WV.  In WV,  the characteristic spruce-fir and northern hardwood habitat of the G. s. fuscus subspecies is relatively abundant, potentially more continuous and at lower elevations, thus suggesting some potential for sustained populations.  The subspecies G. s. coloratus, resides only on high elevation ridges and peaks, and thus occupies habitat islands which are both highly disjunct and of limited size.   It is very limited from southern Virginia to the Smokies due to the more aggressive southern flying squirrel (and, to some degree, a parasite that is transmitted by the southern flying squirrel).  This limited range, along with the possible impact of warming trends, recent droughts and high elevation loss of conifers from introduced insects and acid-rain impacts, suggests a more vulnerable status of this southern subspecies.   These disjunct populations are relics of former broader populations that existed in historically cooler climatic conditions.  Populations have been shown to fluctuate, with peaks reached in the late 1980's in areas studied in WV, VA and NC.
Population Density: <1 to 4/acre.
Size and Molt: Head and body 5 ½ to 6 2/5 inches; 2 - 4 ½ oz. (Weigl's study populations in NC and TN had a mean head and body length of 6" and weight of  3.85 oz.  These are the subspecies G. s. coloratus.)  Females are generally larger than males.  The northern flying squirrel is slightly larger than the southern flying squirrel. (In addition, the northern subspecies, G. s fuscus, is smaller with a more muted pelage than the southern subspecies, G. s. coloratus.  One molt.  Shedd says two molts, unlike the southern flying squirrel.  Shedd also says the northern’s tail molts only once, like the gray, red and southern flying squirrel.  
Mammae: Four pair.
Habitat: In the southern Appalachians, a mixed ecotone of dense coniferous forests and northern hardwood forests (birch/beech/maple/cherry) are favored habitat.  The WV subspecies (G. s. fuscus) is generally limited to habitat over 3,000', while the more southern G. s. coloratus is most commonly found at elevations over 4,500'.  Habitat in this Appalachian region is limited by extent of  spruce forests and competition with the southern flying squirrel.  See remarks below.
Active Period: Nocturnal, primarily in the evening and just before sunrise. Active year-round.  It is known to withstand cold and wet conditions lethal to red squirrels and southern flying squirrels.  Has been found foraging on the forest floor even to -24
° F (Weigl reports -4° F).  However, Weigl found that when inactive and exposed to cold temperatures, the northern flying squirrel will drop it's temperature from ~98 to 86° F and assume a curled position.  Red squirrels under similar conditions are not able to reduce their body temperatures, and thus are not able to survive similar conditions without adequate store.  Southern flying squirrels show an intermediate response, with a slightly reduced metabolism and body temperature.  Weigl notes this reduced metabolism and body temperature is not torpor, since the northern flying squirrel is capable of immediate activity at these reduced levels.
Diet: Somewhat more omnivorous than the southern flying squirrel.  Lichens and fungi, including mycorrhizal fungi (which is a major source of minerals, such as sodium and phosphorus, as well as energy), can constitute a major part of their diet .  The staminate cones of conifers are a major part of the spring diet.  Nuts are eaten, however, less so than the southern flying squirrel due to the absence of oaks and hickories in its range. Also eats buds, fruit, various seeds and a number of insects (beetles and moths). They are known to raid the middens of nocturnal red squirrels during the night.  Will eat meat (young rodents, birds and bird eggs, but less than southern flying squirrel); are known for stealing bait. Creation of food caches in the summer for winter use is contradicted by various authors (as a minimum, the behavior is not as common as with the southern flying squirrel).  It has been found that many of the mycorrhizal forms of fungi that provide food for the forest trees, depend on the dispersal of fungal spores through the defecation of these squirrels.  In fact,  a northern California study correlated the fungal biomass positively with the numbers of northern flying squirrels.
Home Range: 2 ½ - 7 ½ acres. (W/H says 5 - 19 acres or more.) One North Carolina/ Pennsylvania study reported a home range of about 5 acres.  Weigl's North Carolina work found ten squirrels had a mean of 23 acres, with a winter range of 29 acres and a summer range of 15 acres, possibly a function of remote conifer food sources and mate-finding scenarios.
Social Structure: Very gregarious, although not as much so as the southern flying squirrel.  Weigl's study found 33 instances of nest sharing, averaging 2.8 per nest (2-6).  Most groups consisted of only two individuals (13 out of 33) and 15 groups were composed of adults of both sexes.  About equal numbers of all male or all females groups (7 and 4 respectively) were observed.  In groups of three or more involving juveniles, the adult was always a female.  Males do not help in child care.
Life Cycle: Usually one litter with two or four (1-6) per litter per year.  Parturition from April through September, after a gestation period of 37 - 40 days. Weaned in eight to nine weeks, often spending the first winter with the mother, normally breeding the following spring.  Life span 3 to 5 years, with 13-14 years in captivity.
Den/Nest: Prefers woodpecker holes or tree cavities, although even witch’s brooms and mats of moss have been used in northern regions.  Will also use leaf nests (dreys) in spruce trees.  (Being larger than the southern flying squirrel, it must make more leaf nests, since less suitable trees can be found.)  Also uses old crow or red squirrel nests.   Weigl found 12 summer nests included 7 cavities and 5 dreys, with 27 winter nests including 15 cavities and 12 dreys.  Urban (1988) found an almost exclusive reliance on drey nests in WV.  Nests are covered with firmly matted spruce twigs, lined with shredded yellow birch bark, lichens, grasses, sedges, and moss.  Outside nests are 8" - 10" in diameter, and 6" - 8" deep, usually high (14-28') in red spruce (exclusively spruce for Weigl's study).  A single 2" opening leads to the nest.  Weigl found an average of 3.25 nests per squirrel were used.  70% of Weigl's nests were found within 300' of the coniferous/hardwood borders.  A third category of nest is recognized as a retreat nest, of marginal nest quality and serving as sheltered breeding stations, food storage areas or defecatoria.
Tracks: The give away is the "sitzmark", or landing spot, with the pattern of feet leaving the site, much like a gray squirrel, only smaller (rear foot 1 5/8" in length, with a straddle of 3 3/4 inches).
Scat: Indistinct piles, each dropping less than 1/4" in length.

Remarks: The northern and southern flying squirrels are the only two species in the genus.  The northern flying squirrel is much larger and heavily built than the southern flying squirrel. Belly hairs basically white with gray at the base (but occasionally white throughout), while the southern flying squirrel belly hairs are a solid white.  Individuals from the southern Appalachians tend to be darker than northern individuals. Mean average glide is 66 feet, although flights up to 270 feet are recorded (the distance is more a function of height; the glide course is about three horizontal feet for every vertical foot drop).  Their tail allows them a good deal of maneuverability.  In fact, flying squirrels have been observed turning more than 180° during a glide.   Less vocal than the southern flying squirrel.  

The northern and southern flying squirrel are generally not sympatric (occurring in the same area; thus, they are allopatric); the smaller southern flying squirrel being more aggressive and tending to displace the larger northern flying squirrel.  Where they overlap, populations of both are limited and unstable.  Overlap areas generally support one species or the other.  However, where there are good populations of the northern flying squirrel, red squirrel populations are almost always abundant.   There is also evidence of a nematode parasite of the southern flying squirrel that is lethal or debilitating to the northern flying squirrel.  When northern flying squirrels come down from their mountain habitats and come into contact with the southern flying squirrel, it would very likely pick up the parasite and perhaps suffer either sickness or at least a competitive disadvantage.  On the other hand, when southern flying squirrel populations invade the spruce forest habitats of the northern flying squirrel, it cannot store adequate winter reserves of acorns to enable it to competitively survive the winters.  Still, another factor comes into play regarding the nematode.  The staminate spruce cones that make up a significant portion of the northern flying squirrel's spring diet are filled with highly aromatic oils that are known to have some potential as "vermifuges".  It is possible that these cones provide the northern flying squirrel with some protection in the high elevation spruce forests which is lost when it leaves the coniferous forests for the lower elevation oak forests.  Interestingly, it has also been found that the success of the nematode is severely limited at colder temperatures.

With southern flying squirrels found at the highest elevations in Virginia, it does not look good for the future of the northern flying squirrel in Virginia.  

The introduced balsam wooly adelgid will have a major impact on these squirrels by the loss of the nesting sites and food source.  High concentrations of heavy metals found at high elevations in NC (lead, copper, zinc, manganese) can also be harmful to these squirrels.

At night, the eyes of the flying squirrel will shine red by the light of a flashlight.

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SOUTHERN FLYING SQUIRREL (Glaucomys volans) (gray, mouse; flying)

Appalachian Region Distribution: Throughout.
Continental Range: All of eastern US.  Three eastern subspecies recognized in eastern US, with only one in the Appalachian region.
Abundance: Common wherever there are oak/hickory forests.  In fact, often outnumbers the diurnal gray squirrel in mature woodlands. 
Population Density: 1-3/acre, up to 5/acre.     
Size and Molt: Head and body 5 ½ to 5 2/3 inches; 1 - 3 oz. One fall molt.  Females are generally larger than males.  Smaller than the northern flying squirrel.    
Mammae: Four pair.
Habitat: Prefers mature hardwood forests, as opposed to the preferred coniferous forest of the northern flying squirrel, since they rely on stored middens of acorns, unlike the northern flying squirrel.
Active Period: Nocturnal. Does not hibernate, but undergoes periods of torpor and inactivity, more often than the northern flying squirrel (who, apparently, is more used to the cold weather). NAS says body temperatures can drop to 22°F and will take up to 40 minutes to wake.  Tends to aggregate in winter nests (in one study of 841 winter nests, 676 - 81% - had two or more in the nest, and, of those, 79% housed only adults).  16 were found curled together in a wood duck box one February day at the Patuxent Research Refuge in Maryland (50 have been recorded in one nest).  Low body temperatures seem to coincide with larger denning numbers.
Diet: Most carnivorous member of the squirrel family; eating insects, birds, eggs, small mice and shrews, and even carrion. Animal sources dominate summer diet. Winter and spring diet includes buds, catkins, and shoots of trees.  Also mushrooms, berries, buds and maple sap. Forages mainly arboreally. Known to cache food (unlike the scurids, this squirrel hides its nuts above ground in tree hollows. The southern flying squirrel may store up to 15,000 nuts in a season.  Hole eaten in nut is circular with a smooth edge. (It is a single hole versus numerous smaller holes of the mouse.)
Home Range: 1 - 7 acres.  Females are territorial in summer.  Males are less territorial, with broadly overlapping ranges.  A Maryland study a home range of 6 acres for males, 5 acres for females and 1.5 acres for juveniles.   Ranges of males overlapped extensively, with females overlapping very little with other females or males.  
Social Structure: Somewhat gregarious, especially in winter nests.  Very shy.  Males overlap ranges extensively, but females ranges overlapped little among themselves or with male ranges during the breeding period.   Reports vary on male role in rearing young; one says they help raise young, SE Mammals says male kicked out at child birth; raised by the mother, then male reappears for second mating when young are weaned, others make no comment about male role. Gregarious in winter months, with usually three to eight sleeping in the same cavity (although 28 and 50 – in an Illinois tree hollow - have been recorded).   Shedd states the southern flying squirrel is considerably more aggressive than the northern, and generally is dominant where the two species are sympatric.    
Life Cycle: Usually two litters, with two to four per litter per year, born in April and July. Females are polyestrus, in estrus for only one day, with a gestation period of 41 days.  Weaned (and can glide) at eight weeks. Mother and young will stay together until next litter.  Will breed in one year (although many studies show summer births often bear young the following spring). Young females usually have one litter, while older females often have two litters.  Life span of three to five years, with records of up to 13 years in captivity.
Dens/Nest: Dependent on cavities in trees, often  made by woodpeckers (15 - 20 feet above the ground). Has a primary nest and several secondary nests used intermittently as feeding stations and, even some for defecating stations, with openings of 1 ½ to 2 inches. Are known to make summer leaf nests, but being smaller than the northern flying squirrel, it can more often find a suitable tree cavity.  Nests are lined with lichens or finely chewed bark.  Outside nests are 8" - 10" in diameter.  Known to reuse fox or gray squirrel nests, or even bird houses.
Tracks: The give away is the "sitzmark", or landing spot, with the pattern of feet leaving the site, much like a gray squirrel, only smaller (rear foot 1 5/8" in length, with a straddle of 3 3/4 inches).
Scat: Indistinct piles, each dropping less than 1/4" in length.

Remarks: A very small tree squirrel with loose skin between the limbs. Belly hairs totally white, which differentiate the southern from the northern flying squirrel (whose white belly hairs have a gray base). Extremely arboreal, can glide up to 260 feet (normally at a 30 degree slope), although 30 to 50 feet is more common, and capable of turning 90 degrees in mid-flight. Nut-caching fall habits are photoperiodically triggered (short days). Those from SC and western NC are darker than those from MD, VA, and eastern NC. Shy and docile, they make good pets, except they can be quite noisy at night.  

Audubon and Bachman reported seeing at least 200 in and under several large beech and oak trees near Philadelphia.

At night, the eyes of the flying squirrel will shine red by the light of a flashlight.

The northern and southern flying squirrels are the only two species in the genus. 

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Family Castoridae – Beaver

With only two species worldwide, this is truly a small family.  The other species, Castor fiber, is native to portions of Europe and Asia.  Numerous closely related family members existed in prehistoric times, including the Pleistocene and late Tertiary.  One was a 700 - 800 pound, muskrat-like animal that fed on marshy vegetation.  Another extinct group constructed deep, spiraling burrows. 

The beaver, the only species in North America, is the largest rodent in North America, weighing 88 pounds, or more.  Although it is frequently reported that a beaver will continue growing throughout its life, studies indicate that growth basically terminates at age four or five. 

AMERICAN BEAVER (Castor canadensis) (beaver; from Canada)  

ARTICLES

Appalachian Region Distribution: Throughout, due to restocking. Was basically extirpated from eastern US by the turn of the century.
Continental Range: All of North America.  Only one recognized eastern US subspecies.
Abundance: Becoming more common.
Population Density: Depending on habitat quality, studies show .2 to 2 colonies/square mile (up to 8/square mile in ideal habitat)  (one colony equals 4-8 individuals), or one colony per 0.4 - 1.5 miles of stream habitat, up to a maximum of 4.2 per stream mile.  
Size and Molt: Head and body 25 to 35 inches. The largest rodent in the Appalachian region, weighing 35 to 70 pounds, with a record as of 1981 of 115 pounds.
  Second largest rodent in the world, with only the capybara of South America being larger. While many references state that beaver grow continuously throughout their life, others say they reach their practical full size after 3 -5 years.  Beaver are somewhat smaller in the southern part of their range.   It can be assumed beaver found in Appalachian streams and rivers will be on the small size, based on food quality and quantity compared with coastal marsh/ broad piedmont-coastal plain rivers.  One molt.
Mammae: Two pair.
Habitat: Live along water courses having adequate tree supply.
Active Period: Nocturnal and crepuscular, year-round. Most active in the fall to repair the dam and create a food cache.
Diet: Vegetarian, feeding on the cambium layer of buds and twigs in winter, aquatic plants and grasses in summer. A colony of 6 to 8 beaver will consume about 1,000 trees a year.  Known to "mow down" an entire aspen forest before other trees are eaten.  Coprophagy is known to occur among beaver.  Beaver are unable to digest cellulose any better than any other non-ruminant mammal, thus, large quantities of woody fibrous material must be eaten.  Will cache branches in fall underwater (cache can be ten feet high and forty feet wide) for winter food, which, in the north, must last for up to six months.  Caches are not cut until after the sap has returned to the roots, minimizing chance of spoilage.  In the south, such caches are not made.  In addition, brown fat, stored in the tail, is utilized to provide needed winter energy.  One study found witch hazels were cached for food, while maple was eaten on the spot.  Beaver will discriminate among aspen trees, “testing” the bark on aspens, and selecting those individuals with a lower concentration of natural toxic plant compounds in the bark.
Home Range: Within 660 feet from the lodge.
Social Structure: Monogamous, gregarious and very territorial (as a colony).  The social structure of a beaver colony is based on the mating pair.  Living together in a lodge, beaver live in social units of about 6, consisting of a mating pair, the yearlings, and the kits (and occasionally one or more that are about 2.5 years old).  Larger colonies (up to 12 members) are found in higher quality habitat.  Most sources say beaver mate for life (monogamous).  PA mammals says the female is reported to mate for life, although males are polygynous.  There usually is only a single breeding female in a colony.  The female appears to be dominant over both males and young most of the time.  Bonds normally last only a few years, with the death of one of the mates.  At this time, a member of a younger generation from another colony replaces the adult.  This difference in age in the couples is common. It is normally the female that selects the home site.  If the paired male dies, the female remains at the existing site.  If the female dies, the territory may be abandoned.  The two-year olds are driven off (or instinctively disperse) a few miles to establish their own range (one to five miles upstream or downstream), at which time they have reached sexual maturity. Castor scent mounds are made to stake a claim, which may lead to territorial fights, or the finding of a unmated beaver of the opposite sex.  Family unit will protect home territory from other beaver, although more than one family may share a lake.
Life Cycle: Usually only one litter with three to four per litter per year. Adult females may not successfully reproduce every year.  Mating occurs from December through February, with birthing from April through June.  Copulation occurs in the water.  Estrus lasts two weeks, with the female being receptive for 10 to 12 hours.  The gestation period is variously reported to be from 98 to 128 days.  Precocial young, weaned after six weeks (but may last for more than 3 months), live with the parents for two seasons until forced out prior to the third litter. Highest mortality occurs at this time. Until young reach 30 days of age, high buoyancy prevents them from submerging and leaving the den.  Sexual maturity is reached at two or three years of age. This is an extremely long time for rodents, and may reflect the learning and experience required prior to setting off on its own.  Life span of 15 is considered maximum, with one reaching 24 in the wild.  Some beaver in captivity have attained ages of 35 to 50 years in zoos.
Den/Nest: Lodges are along the bank or on islands measuring six feet high and 12 to 15 feet in diameter. The inner chamber is six feet wide by two feet high.  Lodges are added to throughout the lifetime of the beaver and may get to be eight feet high and forty feet across.  After the major initial construction of the lodge is completed, the beaver dives underwater and cuts his/`her way into the center of the mass.  When they are above the waterline, they cut out a chamber that will be 3-4 feet across and perhaps 18-24' high.  Normally, two levels exist; a lower level, only 3-5" above the waterline for feeding and preening, and an upper level, 8-10" higher, used for bedding.  Several entrances into the lodge may exist.  A small air hole, or chimney, is made in the top for ventilation.  The outside is coated with mud for insulation, waterproofing and defense in winter (when it freezes rock hard).  Only the peak of the den is not mud coated, functioning as an air vent.  Occasionally, a winter lodge is also constructed, in addition to the summer lodge.  Beaver won’t make dams in watercourses of adequate depth (or swift current). Dens will be made in the banks in these circumstances ("bank beavers"), with burrows as long as 30'.  Occasionally, in beaver colonies, both lodges and bank dens will be made.  Scent mounds (mud and vegetational debris, 8-10" high and 10-12" wide) are placed in piles near the colony territorial boundaries and wetted with urine, castorium, and perhaps contents of the oil or anal glands.
Tracks: Notice the webbed rear feet, approximately 6" long by 5" wide, often obscured by the dragging tail.  Often along heavily used trails from the body of water into the woods.  Four toes in front and five toes in rear.  The front foot can have a grooming spur on the side so it looks like five toes in front. Another sign of beaver is the scent mound, or sign heaps; a mound of soil about a foot high scented with castoreum marking the beaver's range.  There may be over a hundred scent mounds throughout the home range.                  
Scat: As noted above, beaver practice coprophagy.  Using microbial action in the caecum, located between the large and small intestines, to ferment digesting fibrous tissues, a soft green fecal material is produced, which they reingest.  Another kind of feces, not reingested, is usually excreted in the water (in fact, it is difficult for beaver to defecate out of water), thus, it is unlikely to find beaver scat.  They consist of oval pellets of coarse sawdust-like material, 1 1/4" long by 3/4 inches wide.

Remarks: Beaver are more specialized for swimming than any other rodent.  When beavers swim, only their head is exposed, while both the head and back are exposed with the muskrat.  On land, a mother can carry her kits on her tail,  or even walk erect and hold them in her forepaws.  Beaver have been observed walking bipedally, carrying a bundle of twigs in their arms. 

Beaver have scent glands (castor glands) at the base of the tail which produce a bitter, orange-brown secretion known as castoreum, used in the making of perfumes. Most of the oil is shipped to France or Orient for processing.  The tail is important in temperature regulation, fat storage, and as a means of communication.  Rarely, a beaver will be killed by a falling tree cut by the beaver. When alarmed, beaver will slap the water surface with their tail and then submerge. Beaver, as well as other rodents, keep their incisors worn down by grinding their teeth together; not by constantly chewing wood, as is often believed. In cutting, beaver use their upper front teeth for leverage, the actual cutting being done only by the lower ones.  The outer surfaces of the large, ever-growing incisors are covered by an orange layer of enamel, harder than the enamel of most mammal’s teeth because iron is substituted for some of the calcium.    

Beaver stay underwater for ten to fifteen minutes.  This is due to a metabolism that slows down to half its usual rate underwater and an extremely efficient oxygen uptake within the beaver’s lungs, which can use 75% of the available oxygen, versus only 15% of man.

Beaver tails act to store brown fat as a winter food reserve, a rudder in swimming, a fifth leg, and as a warning to other beavers of danger by slapping the water surface.  Interestingly, beaver ignore the slaps of certain beaver, as they do most juveniles.  Yes, they can distinguish among beaver by their tail slap.

Dams are made as a means of protection for the beaver (they can hide in the water).  An average dam will be 5 to7 feet high and 75 feet long.  Many dams will be over 1,000 feet long, with a few reaching over 2,000 feet.  The record dam, measured in Montana, was 2,154 feet long, or 0.4 mile.  Dams have been found that are ten feet high in narrow gorges.  When all of the nearby trees have been cut, the beaver will make canals reaching up to 100 feet.  They not only facilitate food gathering but also allow the beavers to escape from predators.  The stimulus for building dams seems to come from the sound of running water.

It can be reasonably stated that the beaver trade allowed the settlement of North America.  Although nearly extirpated in the eastern US, E. T. Seton suggests that there were as many as 60,000,000 beaver in pre-colonial times in North America.  

Beaver were extirpated in Virginia between 1885 and 1911.  Between 1932 and 1938, 35 were released in nine VA counties.  By 1943, enough had reproduced that surplus beaver were redistributed to new areas, with trapping started in 1953.   

Beaver in West Virginia were extirpated by 1923.  It was reintroduced during the period of 1933 through 1940 in Randolph, Pocahontas, and Tucker Counties.  Since that time, they have spread throughout the state, though most conspicuous in the Canaan Valley.

Roughly, 500,000 total pelts have been harvested annually from Canadian and US, based on reports from 1950 to 1977.  In the process of trapping beaver, usually one river otter is caught for every 8 to 10 beaver, in addition to mink and raccoon in water sets and bobcat and fox in land sets.  In one season, (1976/77),  45 states in the US recorded a total harvest of 232,710 pelts.  During the 1983/84 season in Canada, 341,354 pelts were taken.

Due to the increase in beavers in northeastern US, the moose population has also increased, benefited by the ponds made by the beaver.  Other species benefiting from the beaver’s operations include muskrat, otters, fish, waterfowl, cavity-nesting birds, amphibians and reptiles.  Once all the trees within 300 to 600 feet to the dam are cut, the beaver move.  Even after the beaver leave, the remaining beaver meadow provides habitat for numerous plants and animals.  Eventually, trees and shrubs revegetate the meadow, and, ultimately, the beaver come back and the cycle starts over again.  

Beaver have been bred to produce strains with white, blue, jet black and golden pelts.

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  Family Muridae - Mice, Rats, Lemmings and Voles

This family is the largest family of mammals in the world, as well as in the eastern United States. They make up about 25% of all of the known species of mammals.  This family includes many small to medium-sized rodents. Additionally, the larger muskrat is included in this family. As a whole, the Muridae family is usually nocturnal and omnivorous, has multiple litters and does not hibernate. They have varying habitats from arboreal, terrestrial, subterranean to aquatic.   Tails are rarely bushy. Mice and rats have large ears and eyes with long tails, while lemmings and voles have small ears and eyes with short tails.  Most have four front toes (some five) and all have five back toes.  Nests are commonly shredded grass and leaves forming a 6 to 8 inch diameter sphere.  

Mice and voles have four front toes and five hind toes approximately ¼ to 3/8" wide. Vole trails are wider than shrews, averaging 1 ½" wide, often without a tail track, as is common with shrews. Both shrews and voles tunnel in snow.  Mice generally do not tunnel and can be identified by their galloping trail, which resembles a small squirrel, with sets of prints (often including tail print) a few inches to a few feet apart.  Entrance holes are generally 1 ½" in diameter.  Mice generally use holes and tunnels made by voles and moles.

The Muridae family is subdivided into three subfamilies; the Arvicolinae, Sigmodontinae, and the Murinae. 

The Arvicolinae subfamily includes voles, lemmings and muskrats.  These rodents tend to be compact, short-tailed, round-headed creatures.  Originating 70 million years ago, it wasn’t until the recent Pleistocene epoch (1 million years ago)  that they exploded in their speciation.  Voles and lemmings are the dominant small mammals of the far north and provide the major food source for predatory mammals.  They have extremely high reproductive rates, exhibit post-partum estrus, quick sexual maturity, and short pregnancies.  Most have 8 mammary glands.  Such factors have combined to enable one meadow vole to have 17 litters in one year with 83 offspring and 78 grandchildren before her first birthday.  Of course, in nature, high fecundity must be reflected in high mortality.  The average life expectancy of the meadow vole is one month, with one year being reached only in ideal conditions.  They also exhibit population fluctuations ranging from 1 to 1,000’s per acre in a three or four year cycle.  They are all herbivores, benefiting from having grinding teeth and a enlarged intestinal chamber for fermenting the low-value foods.  Many practice coprophagy.  Voles and lemming do not drink water, but gather it through the vegetation. 

The Sigmodontinae include white-footed and deer mice, harvest mice and wood rats. 

The third subfamily, the Murinae, include the introduced house mouse and two introduced rats.  Although there is no biological difference between rats and mice, rats are generally larger.

World-wide, the Muridae includes 281 genera and 1,326 species. 

There are 14 genera and 26 species in the eastern United States, of which 9 genera and 15 species are represented in the Appalachian region (Jones).

    Subfamily Sigmodontinae

EASTERN HARVEST MOUSE (Reithrodontomys humulis) (groove-toothed mouse; small)

Appalachian Region Distribution: Extirpated in  Maryland; now found to the south.  
Continental Range: SE US.  Two subspecies have been recognized in eastern US and in the Appalachian region.
Abundance: Uncommon in mountains. 
Population Densities: Tends to be found in localized populations of 4 – 10 per acre.  One record of 90/acre has been recorded.
Size and Molt: Head and body 2 3/5 to 3 inches; ¼ - ½ oz.  Smallest rodent in the Appalachian region.  One molt.
Mammae: Six
Habitat: Inhabits old fields, marshes, and wet meadows. The greatest numbers have been found in broom sedge.  Shares habitat with least shrews, meadow mice, and golden mice.  Seldom found in forests.
Active Period: Nocturnal, active year-round.
Diet: Weed seeds, butterfly and moth larvae (caterpillars), shoots of vegetation, and some insects. Some caching of seeds has been identified. 
Home Range: ½ - 1 acre, with male range being larger than female.
Social Structure: Somewhat gregarious.  Females protect the young for the first three weeks (known to pull young back into the nest when alarmed).  Males are normally not part of the family unit, making their own nests.
Life Cycle: Breeding throughout the warmer months, beginning in March.  Three litters averaging two to four (1-8) per litter.  Young can breed at eight to twelve weeks. Gestation period of 21 days. (One female in captivity had eight litters in 11 months.)  Weaning in two to four weeks.  Life span usually less than one year.
Nest: A baseball-sized (4") globular nest, made of shredded grass and plant fiber, either on or just above the ground in brushy shrubs.  These single-opening nests are utilized by the harvest mouse year-round, as these mice do not hibernate.  Occasionally, a winter nest is located in burrows and small crevices.
Tracks: You’ve got to be kidding.  Did you see how small this gu
y is?  They use runways of other rodents. 

Remarks: The smallest mouse (and rodent) in the SE and one of the least known mammals. An excellent climber. Cotton rats and eastern harvest mice occupy similar habitats, but are not found together, suggesting mutual exclusion (see habitat above). 

Originally described by Audubon and Bachman.   

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WHITE-FOOTED MOUSE (Peromyscus leucopus) (might be Greek with pero meaning "defective" and myskos meaning "mouse", or Latin with pero meaning "pointed", or little pouched mouse; white-footed)

Appalachian Region Distribution: Throughout.
Continental Range: East of the Rockies and lacking in the SE piedmont and coastal plain.   Four subspecies known in eastern US, with two in the Appalachian region (two on islands, including Martha's Vineyard).
Abundance: Both the white-footed and the deer mouse, members of the Peromyscus genus, are the most common rodents in many habitats in the Appalachian mountains.
Population Density: 2-15 per acre.  One study  in Virginia showed a mouse population increase from 1 to 42/acre after a good mast year, only to fall back to 5/acre the next year.
Size and Molt: Head and body 3 3/5 to 4 1/5 inches; ½ - 1 oz. Two molts. Nowak says one molt.
Mammae: Three pair. Nowak says four or six.
Habitat: Brushy areas, deep woodlands or wooded forest edge areas. Warm, dry hardwood forests rather than cool, moist coniferous forests.  Also takes up residence in homes.  Generally found at lower elevations than deer mice, but large overlap occurs considerably.
Active Period: Principally nocturnal, with diurnal tendencies in winter.  Non-hibernators.  By mid-October, mice begin to communally nest in trees.  In mid-winter, communal nests are moved to below ground.  Even during the coldest weather of winter, most white-footed mice remain active.  Some become torpid, with body temperature dropping from 96 to 65
°, and breath rate decreasing from 700 to as few as 60 per minute.  Has been recorded huddling with deer mice. Communal nesting, nesting below ground, and torpor are all energy-saving adaptations against cold that can yield an energy savings of nearly 75%.
Diet: Omnivorous.  During fall and winter, up to 75% of the diet is made up of arthropods (insects, centipedes, spiders). Stokes says nuts and seeds, supplemented by over-wintering insects and leaves/twigs.  Summer diets include up to 50% seeds and fruit, but insects are still a staple. Is known to cache food in the fall for winter.  Stokes says caches food year-round. Rose hips from multiflora roses, cherry pits and jewelweed seeds (Impatiens) are  favored foods.  Tends to eat more insects than the deer mouse.  (A Smokies summer study found seeds to comprise 2.2% of the total volume for the white-footed mouse, while they comprised 57.7% of the deer mouse summer diet.
Home Range: 0.2 - 3 acres, with males having larger home ranges. Ranges are generally larger in summer than winter.  Nowak reports a northern VA study finding an average home range of 0.25 acres for both sexes, while a Quebec study found home ranges of 3.15 acres for males and 2.28 acres for females.  Females sometimes have the better quality habitat.  When that happens, the female is bigger than the male.  Females are often more aggressive in protecting their territory, especially when on a nest.  Intruding females will almost always kill the young of another female.  Males occupy home ranges overlapping those of one or more females.  Female home ranges overlap male home ranges, but the home ranges are mutually exclusive within sexes.
Social Structure: Nests may be shared by pairs or families and for winter grouping.  Both sexes share in the child rearing (the males to a lesser, and not clear how often, extent).  Normally polygamous, but can be monogamous, and in one case, it appeared to be polyandrous (one female and several males). Promiscuous.  Females reside in non-overlapping home ranges maintained by mutual avoidance at low densities, by overt aggression at high densities.  Males occupy home ranges overlapping those of one or more females, and mate with the included females.  While the male may share the nest with a female, but he is evicted at partus, perhaps as a protection against infanticide, being allowed to return at a later date.  Both members of the Peromyscus genera in this Appalachian region behave territorially as one species; defending their territories against other animals of either species.  See remarks below. 
Life Cycle: Three to four litters with an average of four per litter per year (less in the southern range).  Mammals of Virginia presented five-year studies at Mountain Lake, with an average of 1.4 litters per year.  One female is known to having given birth to 26 litters over a two year period, and another; 14 over a twelve month period.  Gestation period of 21 – 23 days (up to 37 days when the female is nursing).  Females are polyestrous, with post-partum heat.  If a female mates while still nursing, a delayed implantation of the fertilized egg will occur for 2 to 7 days.  Young are weaned in 3-4 weeks, dispersing in another month.  Females can breed in 40 days.  Life span of 2 - 3 years.  W/H and Wilson says annual turnover in this species is almost total.  Mammals of Virginia says four to eight months in the wild, with captives living over five years.         
Nest: Nests of both the deer mouse and the white-footed mouse are often made from old bird and squirrel nests in trees. Look in the winter for covered nests. Often winter nests are made in tree hollows or in the ground.  Entrance holes are generally 1 ½" in diameter.  Mice generally use holes and tunnels made by voles and moles.  Will also use abandoned bird houses, especially in winter or to produce its young. Two studies in Giles County, VA revealed deer mice preferring nests high in hollow trees, while white-footed mice favored more variable sites, including ground and underground winter  nests.  When a nest becomes soiled, the mouse will abandon it and build a new one.
Tracks:  Hindprint 5/8" long with 5 toes; foreprint is 1/4" long and wide with 4 toes.  Straddle is 1 3/8", with foreprints printing behind and between hindprints (like squirrels).  Mice and voles have four front toes and five hind toes approximately ¼ to 3/8" wide. White-footed mice and deer mice, unlike voles, do not create tunnels through the grasses, nor do they dig burrows.  However, they will use the tunnels and burrows of voles and other small mammals if available.
  Mice can be identified by their galloping trail, which resembles a small squirrel, with sets of prints (often including tail print) a few inches to a few feet apart. 

Remarks: This genus, which includes the white-footed and the below described deer mouse, are by far the most common of the rodents.  Members of the Peromyscus genus are considered physiological generalists, thus explaining their ubiquitous nature and variable diet.  The reproductive characteristics are readily modified in response to environmental conditions.  Litter size is greatest in the northern regions.  At low population densities, most juveniles attained maturation by fall; at high densities, they often did not.  The presence of an adult suppresses maturation in juveniles.  This seems to encourage dispersal and certainly reduces in-breeding.  Members of both these species behave territorially as one species, defending their territories against other animals of either species.  They will be more defensive of their territories at high densities (10 per acre); especially females.  Good climbers. One of the first small mammals to colonize reclaimed strip mine sites and clearcuts. Aka woodland deer mouse, the tail is equal to, or shorter than, the head and body length and is indistinctly bi-colored. 

The tail of the white-footed mouse is usually slightly less than half the animal's body and head length (~75mm).  It is indistinctly two-toned.  The deer mouse has two forms; the woodland and the prairie form.  Both have a tail that is distinctly bi-colored, being dark on top.  However, the forest form's tail is longer than, or equal to it's to body and head (~90mm), while the prairie form's tail is much less than it's body and head (~50mm).

In the Appalachian region, this species can easily be confused with the larger, long-tailed forest form of the deer mouse (see below); both often sympatric (found together).   Where the two coexist, the deer mouse is much more apt to climb than the white-footed mouse.

The white-footed mouse has a larger and paler race that is normally found in the southern Appalachians from MD south.

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DEER MOUSE (Peromyscus maniculatus) (either Greek with pero meaning "defective" and myskos meaning "mouse", or Latin with pero meaning "pointed", or little pouched mouse; hand)

Appalachian Region Distribution: Throughout.
Continental Range: The most widespread rodent in North America.  All of North America, except south and east of the Appalachian region and far north.  Quite messy regarding the number of subspecies.  As many as 57 subspecies have been recognized in North America.  However, W/H only recognizes two subspecies in eastern US, with one in the Appalachian region.  The subspecies of deer mice segregate into two broad categories; long-tailed, large-eared forest inhabitants and short-tailed, small-eared open country forms. See remarks below if you're into this sort of thing.
Abundance: One of the most common mice in the Appalachian mountains, but known for their population fluctuations.  
Population Density:  Normally from 0.4/acre to 10/acre, with a range up to 36/acre, with some populations being colonial in winter.  Populations fluctuates in 3 – 5 year cycles. 
Size and Molt: Head and body 2 4/5 to 4 inches; 2/3 - 1 ¼ oz. Two molts.  Nowak says one molt.
Mammae: Three pair.  Nowak says two or three pair.
Habitat: Quite diverse, preferring woody or brushy areas, also coniferous forests.  Prefers cool, moist forests and is found most abundantly at the higher altitudes, while the white-footed mouse tends to occur in greater numbers at the lower elevations.  In general, favors more moist habitats than the white-footed mouse.  Nowak says it does not regularly occur in moist places.  In the Smokies, these two species come together at about 3000’.  However, there is considerable overlap.
Active Period: Strictly nocturnal (versus the diurnal shrews and moles). (Wilson says nocturnal and crepuscular.)  Active year-round, but enters torpidity and employs communal nesting (occasionally with white-footed mice) during winter cold spells.
Diet:  More primarily a seed eater than the white-footed mouse.  Its diet includes seeds, fruit, nuts, fungi (Endogone), insects, centipedes, and green vegetation.  Also, insects may make up to about 10 - 20% of their diet.  Makes food caches of nuts and seeds for winter food.  
Home Range: ½ - 3 acres.  W/H says 25,000 to 32,000 square feet, not including the arboreal dimension.  Males usually have larger home ranges than do females.  Nowak reports an average home range of 2.5 acres for males and 1.5 acres for females.  Females are often territorial during the breeding season.
Social Structure: Promiscuous.  See remarks for the white-footed mouse.  Usually solitary, except a brief stay after mating, and during cold weather, where up to 13 individuals have been recorded huddled together.  Nowak reports a Canadian study (Banfield) that considers the deer mouse to be a sociable mouse, tolerant  of other sexes and ages.  Banfield further finds the male lives with the family and helps care for the young.
Life Cycle: Litters are three or four with an average of five (1-9) per litter per year with sexual maturity at six weeks. Gestation period of 23 - 29 days. Exhibits post-partum estrus. Young are weaned in 3-4 weeks, dispersing when sexually mature in six weeks.  Life span of 1.5 to 2 years, although up to 8 years in captivity. 
Den/Nest: Entrance holes are generally 1 ½" in diameter.  Mice generally use holes and tunnels made by voles and moles.   4" spheres of grass lined with down from plants or with shredded materials in trees, stumps, under logs, stumps and boulders.  As nests are soiled, another nest will be made, so that several nests are made in the course of a year.  Nests of both the deer mouse and the white-footed mouse are often made from old bird and squirrel nests in trees. Look in the winter for covered nests.  Two studies in Giles County, VA revealed deer mice preferring nests high in hollow trees, while white-footed mice favored more variable sites, including ground and underground winter  nests.
Tracks: Hindprint 5/8" long with 5 toes; foreprint is 1/4" long and wide with 4 toes.  Straddle is 1 3/8", with foreprints printing behind and between hindprints (like squirrels).   Mice and voles have four front toes and five hind toes approximately ¼ to 3/8" wide.  Mice can be identified by their galloping trail, which resembles a small squirrel, with sets of prints (often including tail print) a few inches to a few feet apart.  When moving rapidly, they leave two closely spaced pairs of tracks, unlike the trotting gait of shrews and woodland voles. The tail often leaves a mark in the snow or sand. White-footed mice and deer mice, unlike voles, do not create tunnels through the grasses, nor do they dig burrows. However, they will use the tunnels and burrows of voles and other small mammals if available.

Remarks:  Two subspecies exist: one (Peromyscus maniculatus maniculatus) being a large, long-tailed (equal to the head and body length), big-eared woodland form and the other, (Peromyscus maniculatus bairdii) a much smaller, short-tailed (much less than half the total length), small-eared field, or prairie form.

This presents an interesting example of the difficulty of taxonomic placement.  These two morphological and behavioral types occur together geographically in large areas of Pennsylvania, New York and Michigan, but in different habitats.  However, they apparently intergrade through a series of populations in Wisconsin and Michigan.  Thus, the overlapping populations have well-developed secondary isolating mechanisms and are acting as true species, whereas, the Wisconsin populations are not even separated by primary isolating mechanisms.  This situation is called “circular overlap”.  Quoting from W/H, “If the two forms are deemed separate species, then one is in the position of accepting the fact of intergradation between two “species” in Wisconsin.  But if they are called separate subspecies of one species, then one has two “subspecies” occurring together but not breeding.  The latter choice, the more conservative of the two, is generally accepted.” 

In addition to these two subspecies, there are two “races” in the Appalachian region within the larger woodland subspecies; one with a longer tail, and one with a shorter tail. The common race is the long-tailed, found throughout the Appalachian region. The short-tailed race is a recent immigrant of the MD-VA coastal plain and piedmont regions. (There are other examples of long-and short-tailed forms of P. maniculatus , and other examples of circular overlap within this species in the western US.  In general, the longer tailed race is the more arboreal. (From what information I’ve read about these Peromyscus, it appears there are many more master’s theses to be had here.)

Both subspecies are similar to the white-footed mouse, Peromyscus leucopus, which is essentially intermediate in several characters between the two.  The tail in the white-footed mouse, however, is less distinctly bicolored and is just slightly less than half the total length of the animal.

The deer mouse is more common at higher elevations than the white-footed mouse. Range overlaps at 2,000’ in SNP and 3,000’ in Smokies.  Where the white-footed and deer mouse are sympatric, the deer mouse is more apt to be arboreal.

Deer mice are commonly used as research animals.  

The first documented case of hantaviruses in North American were diagnosed in May 1993, when several Native Americans died of a respiratory aliment on a reservation in Arizona.  The first case east of the Mississippi was confirmed in January 1994, when a man in Indiana died.  Apparently, hantavirus had been present nationwide for some time, but had gone unrecognized.  Hantavirus has been found in a number of other closely related mice species, including the white-footed mouse.

The deer mice and white-footed mice are major hosts in Lyme disease.  The mice are hosts to the larval stage of the tick that carries the bacterium.  

Deer mice may be destructive to forest regeneration due to its propensity to feed on tree seeds, especially conifer seeds.

Wilson adds that deer mice are scansorial; meaning being able to climb.  How that differs from arboreal, I don’t know, and frankly, my dear…   

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GOLDEN MOUSE (Ochrotomys nuttalli)

Appalachian Region Distribution: It is found from central Virginia south.                        
Continental Range: Southeastern and southcentral US.  Four subspecies recognized in eastern US, with basically only one in the Appalachian region.
Abundance: Common and localized, especially south of the Appalachian region.
Population Density: Nowak reports 1.25/acre in TN, a range from 1.2 - 17/acre in the Smokies, and from 4.25 - 185/acre in Illinois.  W/H reports 2.8 to 3.6 per acre.  
Size and Molt: Head and body 3 2/5 to 3 4/5 inches; 2/3 - 1 oz.  Two molts.
Mammae: Three pair.
Habitat: It is an semi-arboreal species, often found 30 feet above the ground, running adeptly along narrow branches.  Found in a variety of habitats, commonly dominated by greenbriar or honeysuckle.  In the mountainous areas, they occupy the pine and greenbriar thickets, talus slopes of dense hemlock forests, and on the edges of sedge fields.  They are more common in lowland, heavily forested floodplains with extensive undergrowth of greenbriar or honeysuckle.
Active Period: Nocturnal to crepuscular.  Active year-around.
Diet: Omnivorous; preferring seeds of greenbriar, cherry, sumac, dogwood and insects.  Golden mice have cheek pouches, like chipmunks, and carry their food to their feeding platforms to eat.
Home Range: W/H says 0.1 to 1.5 acre.  Difficult to compare with other mice, since their arboreal nature adds a vertical dimension to their range. Home ranges overlap extensively.
Social Structure: Known to be gregarious, with as many as eight having been found in the same nest.  In captivity, the male and female remain together until the birth of the young, at which time the male leaves.  
Life Cycle: Four or five litters with an average of two to three (1-4) per litter per year, weaned in 21 days, with sexual maturity at six weeks.  Post-partum estrus enables an interval of 25 days normally occurring between litters, from mid-March through October.  One captive female had 17 litters in 18 months.  Gestation period of about 25 days. Life span of two and ½ years (one of longest living of the small rodents).  (W/H says averaging 6 - 7 months.)  One has lived in captivity for eight years five months; the longest life span recorded for any species of North American rats or mice.  Despite their long life span, they are born more advanced than most mice, walking on their first day, and hanging upside down by their tail on day four.
Nest: Makes several summer tree nests (neat, compact, 5 - 8" globe-shaped balls) 1 to 15 feet above the ground (NAS says up to 30'), in greenbriar, honeysuckle, conifer or other trees, covered with grass, leaves, or coniferous leaves and lined with finely shredded bark, feathers or fur. These nests may be formed around abandoned bird nests and may be used by successive generations for several years.  They construct many feeding platforms, 5 to 10 feet (or more - Nowak reports 45 feet) above the ground (a ratio of 6 platforms to 1 nest). Makes underground nests in winter and occasionally under logs and rocks in summer. Larger nests can be home to several mice (as many as eight have been found in a nest).
Tracks: Its feet are similar in size to the deer mice.

Remarks: The golden mouse is the single species in the genus Ochrotomys.  

One of the most beautiful and unique of the native mice.  A medium sized mouse with a striking golden cinnamon or burnt orange coat.  Those in the Appalachian region are duskier reddish brown in color and larger than those found in the piedmont.  

An arboreal species, with a prehensile tail, used to wrap around limbs.  Rather docile (easily handled - good pets). 

Audubon and Bachman described one subspecies of the golden mouse.

The golden mouse is abundant in the Dismal Swamp.

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APPALACHIAN WOODRAT (Neotoma magister)(new, sharp: ?)

Appalachian Region Distribution: Throughout.
Continental Range: Found from Pennsylvania and south along the Appalachians to the Smokies; west, throughout the Ohio valley, but lacking in the eastern coastal plain and piedmont.  No subspecies described.
Abundance: Disjunct populations throughout.  Declining in populations, especially in the northern range, being extirpated in New York in 1987 and most of eastern PA and New Jersey (one site still extant) and threatened in Pennsylvania, Ohio and Maryland. Recent work indicated that, aside from their apparent disappearance from Fairfax County along the Potomac, woodrat populations are stable in Virginia. 
Population Density: 1-2 acre.  W/H reports about 70 animals along a 3200 foot bluff in southern Indiana.
Size and Molt: Head and body is 8 - 9 inches; 7 - 12.78 oz.  (W/H  reports an average of 9.48" and 12.95 - 15.93 oz for ten adults from New York, PA and WV.)   Size decreases in the southern range.
Two molts.
Mammae: Two pair.
Habitat: Much more specific as to its habitat needs than the eastern woodrat.  Limited to caves, cliffs and mountainous rocky talus or scree areas (some excellent communal nests are found on the back side of Old Rag Mountain, VA in the "reflector oven cave").  Known to be arboreal. The presence of eastern red cedars seem particularly beneficial to them.  They need dense cover, and occur in upland and lowland forest, old fields, grass and woodland edge, hedgerows, cliffs and ledges. Herbaceous ground vegetation less than 40% is preferred 
Active Period: Nocturnal. Active all year.  Cave residents seem to be more active during the daylight hours. 
Diet: Predominantly vegetarians, feeding almost entirely on vegetation (very few insects, unlike white-footed and deer mice). Caches food (twigs and mushrooms) in the fall.
Home Range: 100 square yards.
Social Structure: Varied reports.  Primarily solitary, although some references indicate a colonial nature.  W/H says aggressive among themselves, although referenced one study that found aggressive solitary dominant wood rats and communal subordinants.
Life Cycle: Females have two or three litters (or even four – depending on weather and food availability) from March to September, averaging two (1-4) per litter per year (much less prolific than most rodents). Altricial young. Gestation period of 35 days. Young are weaned in two to three weeks, and can breed at eight weeks, but most don't breed until their second season.  Life span of two to four years.
Den/Nest: The nest is a bulky, football-sized, cup-like structure built of shredded bark and grasses, surrounded by a conspicuous pile (protective?) of sticks, twigs and debris, in, and among, protected rocks, open on top, like bird nests.  Unlike the eastern wood rat (see Remarks below), the Appalachian wood rat almost never builds stick houses that shelter a nest.  Rather, the nest site is often "barricaded" with piles of sticks or other items that may provide an element of protection.  Arboreal nests are known in areas of seasonal high water.   Midden mounds are common (normally made in the fall as food caches), as are debris piles, consisting of sticks, bark, bones, dung of other animals, feathers, and assorted natural and human refuse, near denning sites, perhaps for protection.  Houses are used year-round for life.  Small piles of sticks, fecal pellets, or debris on rock ledges often are diagnostic.  
Tracks:  Front foot is 5/8" long by 3/4" wide; rear foot is 1 1/4" long by 3/4" wide, with a stride of 2 to 3 inches.                                           
Scat: Often accumulated in heaps near the den site, in dense, black tar-like material.  This material may extend over the edge of rocks as a sticky overflow.  Nearby, may also be white-stained urine spots. 

Remarks: Aka the Allegheny woodrat or "pack rat" because of it’s bulky stick nests (and habit of collecting shiny objects); distinguished from house rats by the hairy tails (not scaly). They also have larger ears. Known to rapidly drum with their back feet when disturbed.  Good climbers woodrats frequent cabins in the woods. Wood rats defecate outside the house, in noticeable piles. Despite shared habitat with rattlesnakes and copperheads, woodrats are not part of the snake’s diet.

Recent works (1990, 1992, & 1993) have split the Appalachian wood rat from the eastern woodrat (N. florida), based on DNA, and behavioral and ecological differences. For example, the eastern woodrat is a generalist in habitat while the Appalachian woodrat is a specialist among rock cliffs and talus slopes. Additionally, the eastern woodrat often makes large stick mounds that shelter a nest, while the Appalachian woodrat almost never will. Originally, these two species were accepted as separate species early in this century, then lumped together as a result of studies made in the 40's and 50's.  (Attempts in the 70's to produce hybrids in captivity failed as the N. magister would usually attack and kill the N. floridana.)

Precipitously declining Appalachian woodrat populations appear to be the result of several combined factors; decreased food supplies resulting from defoliation by gypsy moths, infestations by parasites, and raccoon roundworm, transmitted by an increase in raccoon numbers.

Virginia nongame reports from 1992 through 1995 found that there are no longer any viable populations of woodrat in Fairfax, Loudon, Frederick, and Clarke.  

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 Subfamily Murinae - Old World Rats and Mice

Three species, the Norway and Black rat and the house mouse, have been introduced into the New World and have been established over most of the country as pests.  These introduced rodents are characterized by long, naked tails.  The Norway and Black rat carries diseases, including the bubonic plague.  The house mouse, found throughout homes everywhere, is also abundant in agricultural fields and open waste places. 

A summary of general characteristics only will be provided for these three species.


NORWAY RAT (Rattus norvegicus)
(rat; from Norway)

Head and body 7 to 10 inches. This introduced "wharf rat" is identified by it’s long, hairless, scaly tail. First introduced around 1775, this is the ubiquitous rat of warehouses, slums, etc. They maintain a very small range often of less than 200 feet in diameter. Colonies of these rats are common with 10 to 20 individuals, under the rule of male dominance hierarchy. Probably the most omnivorous mammal of all. Breeding throughout the year (averaging six to eight per year) with an average of nine per litter, the young are sexually mature at three months. This species is the source of the laboratory rats, in part, due to it’s remarkably high fecundity rate. Most of the lab rats are inbred pink-eyed albinos.

BLACK RAT (Rattus rattus) (rat; rat)

Head and body 7 to 8 inches. Aka "roof rat", it is often not black, is smaller than the Norway rat, but with a longer tail. Apparently introduced with the Spaniards in Central America in the 1500s and with the Jamestown colonists in 1607.  Unlike the more aggressive subterranean Norway rat, the black rat builds arboreal nests in forested environments. Both often cohabit the same buildings, with the larger dominant Norway rats on the ground and the smaller black rat in the rafters. No interbreeding occurs. Although not quite as prolific as the Norway rat, black rats average six to eight litters with six per litter per year, becoming sexually mature at three to four months. Black rats are not common in the Appalachians, preferring instead, the Piedmont and Coastal Plain.

HOUSE MOUSE (Mus musculus) (mouse; small mouse)

Head and body 3 1/5 to 3 2/5 inches. Another introduced species, the house mouse is found throughout the Appalachian region, usually around buildings, but occasionally in fields. Forming large colonies, these prolific breeders have from five to ten litters of about six per litter per year, the young breeding at four to six weeks. Along with the Norway rat, the albino house mouse is a staple of the lab research crew. They have strong scent glands (musk glands) located near the anus.  

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               Subfamily Arvicolinae -

Voles (which includes the bog lemmings),  Muskrats, and the true Lemmings.

SOUTHERN RED-BACKED VOLE (Clethrionomys gapperi) (kind of dor-mouse, or bolt-toothed mouse; Mr. Gapper)

Appalachian Region Distribution: Clearly, a Canadian (boreal) species that extends south along the Appalachians to about Springer Mountain, Georgia.
Continental Range: Throughout Canada, with southern extensions along the Rockies and the Appalachians.   Seven subspecies recognized in eastern US, with two in the Appalachian region.
Abundance: They are common above 2,000’, often the most common small mammal in their favored habitat.
Population Density:  1-15 acre (up to 26 per acre, decreasing throughout the winter).  Does not exhibit cyclic population explosions, but is extremely variable.  Nowak reports a range from 5 -185/acre.
Size and Molt: Head and body is 3 2/3 to 4 2/3 inches; ½ - 1 ½ oz. Two molts.
Mammae: Four pair.
Habitat: They prefer cool, moist, rocky areas in coniferous forests, especially moss-covered logs and rocks.  Are also found in deciduous or mixed forests. 
Active Period: Active both day and night (primarily nocturnal in summer and diurnal in winter), year-round. Like other voles, they do not hibernate or exhibit periods of torpor.
Diet: Has a more varied diet than other voles due to rooted cheek teeth.  Includes green vegetation, seeds, nuts, bark, fungi (Endogone; making up a substantial portion of the late summer and fall diet), with only a few insects (less than the Peromyscus).  NAS mentions false lily of the valley, goldthread and bunchberry.  Does not routinely cache food in fall, but will store food in the nest for use when the supply is short.  W/H says this vole lays aside large caches of food in November.  Bark and roots are the main winter food stay.  
Home Range: Nowak reports a summer range of 3.5 acres and a winter range of 0.35 acres.  W/H reports 0.02 to 1.2 acres.  One study reported a greater subnivean range (under the snow) in winter than summer range.
Social Structure: Males stay with the female and young for the first month, although it is not apparent that he participates with child-rearing. In captivity, females tend to establish dominance when in breeding condition, and males were dominant when females were not in breeding condition.
Life Cycle: Females have two to four litters per year (starting in mid-March through November) with an average of four to six per litter (3.33 in SE Kentucky).  Larger litters are common – up to 11 - at higher elevations and further north. Gestation period of 18 days. Weaned and on their own in 17 to 21 days with sexual maturity in three to four months. Life span of one to two years.
Dens/Nest: Globular nests of 3 - 4", lined with grass, stems, dead leaves, and moss, under logs or roots, brush piles, or may be in tree cavities, or burrows of other animals.  Although, generally thought of as an inhabitant of the forest floor, several have been caught in nests 7 to 10 feet above the ground.  In the winter globular nests of grass may be placed directly on the ground under the snow, with tunnels radiating from the nest under the snow.
Tracks: Semi-fossorial, they prefer to hunt and travel along shrew and other small mammal tunnels, rather than surface runways.  They will use runways of other rodents, however.  Tends to trot, rather than hopping, like the deer mouse (NAS says they usually hop, but also run). Unlike the meadow vole, the red-backed vole doesn’t make extensive tunnels.  Rather, it utilizes tunnels made moles and shrews with other woodland creatures.
Scat: Concentration of scats is usually found.  Although, fecal pellets may be found scattered throughout a busy area.

Remarks: Aka, boreal red-backed vole. Has a red and gray phase (gray is more common in the north - reportedly the dominant gene and red the recessive gene). Good climbers. Specimens from NC and southern VA are slightly larger and much darker in color than those from northern VA and MD. (W/H says southern Appalachian populations are decidedly larger than their northern relatives.)  May have a cyclic population peaking every few years, like the meadow vole and some lemmings.  Known to girdle fruit trees, and known to have meat that is tender and well-flavored.

Together with the deer mouse, the most abundant species found on the summit of Mount Rogers, VA.  

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ROCK VOLE (Microtus chrotorrhinus) (small ear; yellow nose)

Appalachian Region Distribution: A medium sized vole of NE Canada, the rock vole extends south along the central ridges of the Appalachians continuously as far south as PA. At that point, the next population is disjunct by about 250 miles to southeastern WV and Bath County VA, eastern TN and western NC at high elevations.  Type locality is from
the Great Smoky Mountains National Park, approximately five air miles north of Smokemont , Swain County, North Carolina on a tributary to Bradley fork.
Continental Range: NE Canada, extending south along the Appalachians in disjunct populations to the Smokies.  Two subspecies are recognized in the eastern US.  M. chrotorrhinus carolinensis
is designated as near threatened by the IUCN.  It is endangered in  Virginia because of the logging of old-growth spruce forests.   A second subspecies is found in northern PA and to the north.  
Abundance: Rock voles, although considered rare, can be locally abundant in good habitat (but are usually outnumbered by other species in its habitat).  
Population Density: Unknown, but has a four year population cycle.
Size and Molt: Head and body 4 to 4 4/5 inches; 1 - 2 oz. Males may be slightly larger than females. Two molts.
Mammae: Four pair.
Habitat: It’s preferred habitat is cool, wet, moss - covered (or herbaceous plant-covered, especially bunchberry) talus or scree slopes (often above timberline at Mt. Washington, NH) in northern hardwoods and mixed deciduous-coniferous forests.  It is found in habitats of mixed deciduous red spruce forest along with rock and talus and a ground cover of mosses and ferns.  It may also utilize recent clearcuts.
Active Period: They are active both day and night (primarily early in the day), year-round.
Diet: Green vegetation, roots, fungi, insects and berries.   Supposed foods of the rock vole in New England and Minnesota include blueberry leaves, stems, and fruits; foliage of Clinton's
lily, wild lily-of-the-valley, and bunchberrys; fruit of raspberry and blackberry; and mushrooms. Grasses and sedges may be of lesser importance as food items. 
Bunchberry is known to be a favored food where available.
Home Range: Microtus generally seem to be about 0.25 acres or less.  Males have larger overlapping home ranges than females, and both have protected territories.  Young will disperse during the breeding season, but may remain within the parental range late in the season and overwinter there.
Social Structure: Territorial, living in isolated colonies, these voles share their habitat with southern red-backed voles, deer mice, woodland jumping mice and assorted shrews.
Life Cycle: Litters are born throughout the growing season, averaging two or three litters a year with nearly three per litter. Exhibits post-partum estrus. Gestation period of 19 - 21 days.  Weaned in three weeks.  Chapman and Feldhamer says microtus female may ovulate as early as three weeks of age, with males requiring more than six to eight weeks before sexual maturity.  This helps prevent sibling incest, with females pregnant before male maturity.  Life span of less than  two years.
Nest: They make their nests under or above the ground, made of grass, about 6 to 8", with entrances on both sides. 
Tracks: Utilizes runways beneath and between rocks.
Scat
: Concentration of scats is usually found.  Although, fecal pellets may be found scattered throughout a busy area.

Remarks: Aka the yellownose vole.  It is very similar to the meadow vole, with a reddish orange mark on both sides of the nose and on the cheeks.  

The microtus voles have short tails (less than the body and head) and ears that are nearly concealed by the pelage. 

The existence of rock voles is often revealed by the accumulations of freshly cut vegetation cached under flat rocks at the edges of streams.

Often found in association with the southern red-backed vole (Clethrionomys gapperi).  

Although there has been considerable effort to locate rock voles in Virginia, to date it has been found only in the Valley of Little Back Creek, Bath County.  Rock voles are considered a relict species.  Habitat on Whitetop and Mount Rogers appears suitable. It is likely they occurred in Giles, Tazwell, and Russell counties before the spruce was cut around 1900.

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MEADOW VOLE (Microtus pennsylvanicus) (small ear; from Pennsylvania)

Appalachian Region Distribution: Throughout.
Continental Range: Canada and northern half of US. - as far south as the Smokies. One of the most widely distributed small mammals in the world, certainly the largest of any North American vole.  Five subspecies are recognized in eastern US, with one in the Appalachian region; two restricted to island populations.
Abundance: The most common vole in eastern US.  Wilson says the most prolific mammal on earth.
Population Density: Cyclic populations creates a wide range of figures.  W/H reports a range from 1.6/acre to 73/acres in Indiana.  Nowak reports densities of 92 - 292/acre in old fields and 292-925/acre in marshes, with peak populations reaching 2,500/acre in three or four year cycles.  Annual population fluctuations occur as well as cycles, resulting in boom or bust years.  Cyclic populations seem to be more pronounced in the northern range, but seem to occur throughout the total range at the same time.   Cyclic fluctuations ranged from 166 versus 49 per acre and 36 versus 4 per acre in two Canadian studies.  Such cycles have been observed in VA.  A Giles County VA study reported peak densities of 40 per acre.  Annual populations have been reported to be inversely related to the population of short-tailed shrews.  See remarks below.
Size and Molt: Head and body 3 ½ to 5 inches; 1 - 2 ½ oz. Males are slightly larger than females. Two molts.
Mammae: Four pair.
Habitat: The meadow vole is a relatively large mouse, preferring grass dominated open wet meadows, low, moist fields and openings.  Meadow voles love bluegrass fields.  They spend most of their time above ground. Shares its habitat with hispid cotton rats, meadow jumping mouse, southern bog lemming, and the marsh rice rat. 
Active Period: Active both day and night (mainly crepuscular), year-round.  Will tend to be nocturnal in summer.  Can be active over a 24 hour period, related to season, weather, and habitat quality.  Less active during a full moon (I just write it down).
Diet: They are highly herbaceous, including green vegetation and tubers.  Herbaceous vegetation in summer and bark and roots in winter.  Voles will also eat insects, fungi, and carrion.  They are known to eat their own weight within a 24 hour period.  Meadow voles are also known to practice coprophagy.  In fact, one 1989 study found that meadow voles reingested about 12% of their feces when on a low-quality diet. 
Home Range: 1/10 - 1 acre.   Nowak reports a Kentucky study finding a home range of 358 yd² for males and 167 yd² for females.  Stokes says males are 200 square yards; females 75 square yards.  Wilson says females average 84 square yards. Wilson and W/H says male home ranges are about three times larger than female home ranges and may overlap the ranges of several females and of other males.  Only small areas near the nests will be defended (their "territory"). 
Social Structure: Solitary and territorial during the breeding season and communal in winter.  Both males and females are promiscuous.  Both sexes are seasonally aggressive, with males fighting viciously among themselves, with the females tending to dominate the males.  Breeding females vigorously protect their territory from other females, as can be evidenced by the many chewed ears of captured individuals.  Juveniles from late broods may overwinter with the mother, along with one or two adult males, to form an extended family group (energy conservation through "huddling" can then be gained).
Life Cycle: The most prolific mammal in North America.  Breeding occurs throughout the year (primarily April to November) with an average of eight or nine litters (average of 3.5 in Canada) with a litter size of five to eight (1-11)(postpartum estrus results in new pregnancy within hours of birthing). Largest litters occur in summer.  One female in captivity had 17 litters in one year. Gestation period of 21 days. Weaned in 12 to 14 days, with sexual maturity reached at 25 days for females and 45 days for males. Life span is usually less than a year. One study indicated an average longevity of less than one month.  Populations are often cyclic, reaching highs every three to four years, but this cycle does not always occur.                                       
Nest: The 6-8"spherical grass nest may be located in the burrows in summer or in a depression on the surface under matted vegetation, with entrances on both sides. In the winter, will place the nests on the ground surface if winter snow is reliable.    
Tracks: Hindprint 5/8" long with 5 toes; foreprint 1/2" long, with 4 toes.  Hindprints ahead of foreprints, with distance between individual walking prints (stride) 1/2 - 7/8".       Straddle is 1 1/2".  Like all voles, meadow voles make clear runways in the grass (about 1 ½" wide).
Scat: Small, elongated, dark pellets.  Concentration of scats is usually found.  Although, fecal pellets may be found scattered throughout a busy area.

Remarks: Aka field or meadow mouse.  Often the main small herbivore of open fields.  Known to girdle fruit trees in winter.  Meadow voles invade fallow fields and build large populations until the habitat matures, shading out the herbaceous growth favored by the meadow vole.  Their exploding populations have been known to be catastrophic to agricultural crops, such as in Humbolt County, Nevada from 1906 - 1908, when population densities of 10,000 voles per acre totally denuded 25,000 acres of alfalfa.  Fields were honeycombed by holes up to 24,000 per acre.  (This is attributed to the montane vole; Microtus montanus.)  Members of this genus (Microtines) have adapted to a high-fiber, low nutrient diet, evolving hard enamel grinding teeth and having some of the longest length caecum and large intestines for digestion of herbivorous rodents known.  Meadow voles practice coprophagy (ingesting fecal pellets), primarily in the period of inactivity following the cessation of feeding.  Good swimmers, but not arboreal. Being so prolific, they are a mainstay of the prey for the predatory species. Cyclic populations, with maximums occurring about four years apart, are associated with voles and lemmings, although much research needs to be done to establish the nature of the cycles, which seem to reflect available habitat, and don't have reliable spans of times or densities. 

Populations from Chincoteague, VA, are notably darker than specimens from more northern population, being nearly black on the rump.

Individuals from the southern part of the Appalachians are larger and darker than the northern population.  Can be found sharing the same habitat with the cotton rat, meadow jumping mouse, southern bog lemming, and the marsh rice rat. 

In 1804, Lewis and Clark found and recorded the Indian custom of raiding the underground stores of native mice.   One meadow vole cache included beans produced on the underground shoots of a trifoliate bean vine and artichokes as tubers of a wild sunflower.  

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WOODLAND VOLE
(Microtus pinetorum) (small ear; of the pine grove)

Appalachian Region Distribution: Throughout.
Continental Range: East of the Great Plains and south of Canada.  Seven subspecies are recognized in eastern US, with two in the Appalachian region.
Abundance: Variable.
Population Density: 1-50/ acre. (W/H says up to 6 per acre.)  Not known to have cyclic population booms, rather, they have a K-selected structure; low reproductive rate and a stable population size.  This is possible because of their fossorial nature, making them less susceptible to predation.  None-the-less, fluctuations are known to occur with maximum densities reaching 1,250 per acre.
Size and Molt: Head and body is 2 4/5 to 4 1/5 inches; ¾ - 1 1/2 oz. Two molts.
Mammae: Two pair. (Note this is half as many as the meadow vole - see Life Cycle below.)
Habitat: Prefers a dry, deciduous forest.  A very "fossorial" mammal (subterranean). Wide range, from coastal areas in the south to spruce and birch forests of the northern mountains.  Despite their species name (given from its type location habitat in the pine forests of Georgia), they are more often found in deciduous forests with deep humus, not pine woods (woodland vole is a better characterization). Also found commonly in dense grass, forbs, and brush, orchard, fields and in gardens.
Active Period: Forages both day and night, year-round, mainly underground.  They have a regular pattern of one hour of activity, followed by an hour of rest.  Tends to be more fossorial in summer.
Diet: Grasses, insects, and forbs in summer, seeds and fungi (the subterranean Endogone) in fall, roots and bark in winter.  In addition to grasses and forbs, poke berries, wild onions, and wild morning glories are eaten.  Known to cache food on occasion. More varied diet than the meadow vole.
Home Range: ¼ acre.  W/H says 430 – 485 square feet per “unit”, consisting of two adult males, one adult female, and one or two young. 
Social Structure: Woodland voles can be social and monogamous, with small groups of adults and their young (usually four or five, although 11 has been recorded) living in a single nest. Not territorial, like the meadow vole.
Life Cycle: Postpartum estrus enables many litters (4-6) (NAS says 1-4) throughout the breeding season (from February to November) with an average of two to three (1-5) per litter. Gestation period of 24 days. Young are weaned in 20 days, with males reaching breeding age at 6 to 8 weeks and females at 10 to 12 weeks.  Chapman and Feldhamer says microtus female may ovulate as early as three weeks of age, with males requiring more than six to eight weeks before sexual maturity.  This helps prevent sibling incest, with females pregnant before male maturity.  Female approaches, nay, attacks the male to copulate.  Woodland voles are not cyclic, as meadow voles are.  Rather, they are K-selected; adopting a low reproductive rate and maintaining a stable population (versus the R-selected high reproduction rate and high mortality rate method).  This is reflected in the woodland vole having only four teats, half the number of the meadow vole.  Life span is 12 to 18 months (longer than the meadow vole, as would be expected by the K-selected strategist).
Nest: Unlike the other microtus, the woodland vole is almost wholly subterranean.  The globular nest of dead grasses, roots and leaves (6 -7" diameter ) is found beneath stumps and logs, and at the end of burrows, in a nesting chamber with three or four openings.
Tracks: Woodland voles make their own burrows (1" in diameter) 3 to 4 inches under the surface in the humus layer (although, occasionally tunnels may extend to a depth of 12 inches or more).  In orchards, burrows often follow apple tree roots underground.  They also will take over abandoned mole foraging tunnels, but don’t seal off entrances, like moles do.
Scat: Concentration of scats is usually found.  Although, fecal pellets may be found scattered throughout a busy area.

 Remarks: Aka pine vole. Notice the woodland vole is not a boreal species. These voles are known for damaging orchard trees by girdling the trunk, particularly in the Shenandoah Valley. They also have a preference for potatoes. The woodland vole doesn’t have the breeding potential of the meadow vole, but, being more fossorial (underground), doesn’t lose as many to terrestrial hunters. Also not known to have cyclic population booms.

A fossorial vole, its pelage is especially adapted with short fur that lies flat against the body, whether rubbed forward or backward, like moles.

Woodland voles in southern range have smaller feet and brighter pelage than more northern populations (MD and north).

Often found in the same habitat with hairy-tailed moles, frequently sharing the same burrow systems.  Other neighbors include jumping mice, red-backed voles, white-footed and deer mice, meadow voles, smoky and short-tailed shrews.

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COMMON MUSKRAT (Ondatra zibethicus) (Huron Indian word for muskrat; musky odor)

Appalachian Region Distribution: Throughout.                        
Continental Range: Throughout North America, except SE piedmont and coastal plain and deep SW US.  Three recognized subspecies exists in eastern US, however, only two exist in the Appalachian region.  The species type locality is Lake Drummond, VA, in the Dismal Swamp.
Abundance: More common along lower elevation streams, where adequate habitat is more likely to be found.
Population Density: Extremely variable, based on numerous factors, such as phase of the population cycle, habitat type and condition, social pressures, competition, harvest, predation and geographical area.  Densities range from 3 to 25/ acre.  However, densities in Appalachian regions must be assumed to be much less, due to limited adequate habitat.  Nowak reports 17/acre in open ponds, up to 217/acre in cattail marshes.  W/H reports 2.8 houses (families) per acre.  Wilson says 16 per acre is normal in good habitat, with up to 60 per acre during population peaks.  Densities in coastal marshes have higher densities; up to 122/acre in cattail habitat.  Muskrat cycles of six, ten to 14 years have been recorded, with ten year cycles most commonly reported.  However, such cycles are not exhibited in fresh water marshes.
Size and Molt: Head and body 9 to 14 inches, 2 - 4 pounds (maximum of 5 pounds). Males are slightly larger than females.  It can be assumed muskrats found in Appalachian streams and rivers will be on the small size, based on food quality and quantity compared with coastal marsh/ broad piedmont-coastal plain rivers.  One molt. 
Mammae: Three to four (rarely five) pair of teats are present. Nowak says females usually have two pairs of inguinal and two pairs of pectoral mammae.
Habitat: Marshes, along watercourses. Prefers brackish waters.
Active Period: Nocturnal and crepuscular, but can be active throughout the day.  Active year-round.  Will be more active on cold frosty nights and less active on warm muggy, or windy, nights.  One study found that muskrats do less work during periods with a full moon.
Diet: Mainly vegetarians (principally cattails and bulrush), but is supplemented in winter by crustaceans, mollusks, and fish (apparently affecting the recovery of Federally listed endangered mussels species in SW VA.)  Eats a third of its weight each day.  Like beaver, they can close their upper lips behind the incisors in order to cut materials underwater without taking in water.  Unlike beaver, muskrats generally do not cache food for winter
Home Range: 33 - 600 feet in diameter, averaging 200.  Along rivers and streams, home range has been recorded at 600 feet of linear bank.  Have good homing instincts (31% return when released nearly two miles away).  Males will defend about 5-10 acres from other males; females will defend 2.5-5 acres from other females.  Male territories may overlap those of more than one female.  
Social Structure: Rather territorial (not as much as beaver) and not social, except in winter, when several may occupy a nest (as many as 12 have been found in a winter den - often young offspring).  Males and females have been variously reported as polygamous or loosely monogamous, being especially quarrelsome during the breeding season.  The male is forced out just prior to birthing, but may rejoin the female and young after nursing to maintain the house and to defend a feeding territory.  
Life Cycle: Two to three litters with an average of three to six (1-11) per litter per year is common, with peak breeding period from March -  June, the first brood being born in April.  Polyestrous females, with possible postpartum estrus.  Gestation period of 25 - 30 days. Altricial young. The male rarely cares for the kits.  They are weaned in one month, dispersed soon after weaning (prior to next litter).  Breeding age of one year.  Mortality is high with one study finding as many as 65% of young muskrats dying by January.  Winter harvests are usually composed of approximately two thirds young of the year and one third adults.  Life span does not exceed five years, but ten years in captivity is known.  (Like numerous rodents, litters of more northern populations are less, but have more young per litter.  Sexual maturity is also affected by the length of the season.  In the case of the muskrat, southern populations have 5-6 litters per year with 2.4 young per litter and can have spring young mating by fall, while Canadian populations will have two litters with 7.1 young per litter and not be sexually mature until the next spring. This Appalachian study area falls somewhat in the middle of these two extremes.)
Dens/Nest: Muskrats normally make large grass and reed lodges (two to four feet high and six to eight feet across) in marshy, shallow water (about two feet deep) habitats.   In deep streams, rivers and lakes, muskrats can make their lodges in the banks (thus, the term "bank rats"), forgoing the exposed location of the grass lodge.  Bank burrows are often used throughout the year, or, occasionally, only in summer, with constructed houses in the fall and  "pushups" in winter.   Bank dens generally are 6-8", with depths varying from surficial to over 5', with an air shaft constructed in dense soil.  Such dens are connected to water by numerous tunnels 4-6" in diameter and 9-45' long.  Construction of lodges usually occurs in the early spring after the main dispersal, or in late fall, when a lesser dispersal occurs.   Like the beaver's wood dam, the material is piled up solid, and then the muskrat dives underwater and cuts/digs its way up into the center of the house where it creates its living chamber above the water level.  The size and height of the houses vary, depending on the quality of habitat, range of water level, and number of occupants, but average up to 7-8' in diameter and 1-4' in height.  One-foot thick mud walls insulate both in summer and winter.  Like the bank den, there is usually more than one entrance to the lodge, normally 6” to 12” under the surface.  Tunnels (up to 15’) extend from the dry interior nest area of the house to the surrounding marsh.  Lodges can be used for twenty or more years by generations of muskrats. Lodges normally will hold two adults and two to four young.  Often two internal nest chambers are constructed.  Sometimes, a second house is connected to the first, forming a "double house", and 10 to 15 muskrats may live together.  Usually, houses are dome-shaped structures, but lodges in Maryland often have slanting or flat tops.  Lodge temperatures are about 36 degrees F warmer than outside temperatures.  Makes several smaller, covered feeding huts (or, feeding rafts) near the nest (normally 2' by 2'), where piles of food remains will be found. Like the nest, both have underwater entrances.  These are commonly used in winter, while summer finds them using feeding shelves on the side of their houses.  Within a few yards of the main lodge will be several “pushups”, where muskrats can extend its feeding range when the marsh is icebound.  Muskrats are even known to make nests in hollow logs or stumps, when normal shelter is not available.
Tracks: Tracks are small hands; four toes in front and five toes in rear.  The front foot can have a grooming spur on the side so it looks like five toes in front. Hind foot is 2 to 3" long, foreprint is half as long.  Hindprint can be ahead of or behind foreprint, sometimes overlapping.  Stride of 3".  Canals are frequently constructed from the house to deeper water, or when summer droughts cause low flow, being from seven to ten inches wide.
Scat: Brown, oval, about 1/2 " long and about 3/8" in diameter.  Rue says they look like date pits.  Often uses the same spot on rocks or logs along the edge of the body of water.  Generally, 3 to 4 (up to 12) black, oval droppings are deposited at one time.  Such areas often smell of the strong-smelling yellow musk.

Remarks: This is the only species in the genus Ondatra.  

The semi-aquatic muskrat is classified as a large water vole. Muskrats get their name from the musky odor emanating from the preputial glands found along the penis (especially notable during the breeding season).  Apparently, it is also an adulterated version of the Algonquian word for the muskrat; musquash. They exist, much reduced, in females as well. 

Muskrats benefit other wildlife by creating openings in vegetated wetlands.  

The muskrats main enemy is the mink.  Generally, where you find muskrat, you find mink.  However, 70% of the time, the mink is preying on aged or dying muskrats, not healthy muskrats.  Raccoons are the second enemy, commonly tearing apart muskrat dens, that are not as solid as beaver dens.

Muskrats are more ubiquitous than beaver due to their more omnivorous diet and less demanding habitat.  Unlike the closely related meadow vole, the muskrat does not undergo population explosions, but does have a ten-year cycle of abundance. Muskrats can swim underwater up to 20 minutes without breathing by building up lactic acid in the muscles and bloodstream, a common ability of diving animals (they also have a high tolerance for carbon dioxide). Breaks through ice in winter, pushing up lots of vegetation (pushups), serving as a temporary opening and feeding station. Like beaver and otter, they can close their upper lips behind the incisors in order to cut materials underwater without taking in water.

Muskrats are the most popular fur-bearing mammal in North America.  In the season of 1976-1977, 7,148,370 muskrats were trapped in North America. (200,000 per year in PA.  The same for Virginia for 1984-85.)  Mammals of Virginia says between 10 and 12 million pelts taken every year in North America until recently.  A million pelts taken during the 1987 season in NY averaged $5.00 per pelt.  They are not in short supply.   However, the average price per pelt in Virginia has dropped from $6.90 in 1979 to $0.95 in 1990, resulting in a drop in trapping in Virginia to 15,561 in 1990-91.  Known in the mid-Atlantic markets as marsh rabbits.

The introduction of the nutria from South America (for sport and removal of introduced herbaceous plants) has reduced available habitat for the muskrat, due to the larger, more competitive nutria.  Nutria not only out-compete the muskrat, but literally destroy the wetlands by pulling out the tubers and roots of it’s food sources.  Also, spraying marsh areas with insecticides dissolved in fuel oil to control mosquitoes can cause severe declines in muskrat populations, due to the oil’s wetting effect on the fur, causing the muskrat to sink below the surface and remain thoroughly wet.

Albinism, mutation, and pigment dilution cause color variations from white to black.  A uniform black is found in Virginia and North Carolina marshes; a “fawn” color is found in the Chestertown, MD area; and a “Maryland white” is also identified where young individuals are maltese gray but white underneath.  Generally, muskrats from the piedmont and coastal plain of MD, VA, and NC are slightly darker in color and larger in size than those from the mountains. 

In the category of more than you ever wanted to know, W/H says “Because the clitoris lies anterior to the vaginal opening and resembles the penis, the male and female genitalia are superficially similar.  The distance from the anus to the genitalia is greater in males, and the perineum is furred in males but naked near the urethra in females.

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SOUTHERN BOG LEMMING (Synaptomys cooperi) (unite, mouse; Mr. Cooper)

Appalachian Region Distribution: This is a chunky, medium-sized boreal vole that is found throughout the Appalachians and adjacent foothills as far south as Springer Mountain.
Continental Range: NE US. and SE Canada.  There is a disjunct subspecies in the Dismal Swamp of Virginia/North Carolina which is at least endangered and possibly extinct (S. cooperi helaletes).  Five subspecies are recognized in eastern US, with two in the Appalachian region.
Abundance: Localized in small, isolated areas and generally uncommon.  More common in the mid-west.
Population Density: 2-5 per acre. Mammals of Virginia reports up to 20 per acre, although concurs that 2 – 5 is more representative.  Nowak reports a range from 15-87/acre.  W/H reports 1.6 to 4/acre is usual in good habitat.
Size and Molt: Head and body 3 2/5 to 4 2/5 inches; ½ - 1 ½ oz. One molt.
Mammae: Three pair. (Mammals of Virginia says 6 to 8.)
Habitat: Exceedingly variable.  In this southern part of their range, they are found in wet bogs and cold spring areas.  In the north, grassy meadows and woodlands with heavy vegetation (including clubmosses), and dry hillsides can be populated.  Succulent monocots, such as sedges and grasses seem to be the key.   Small patches of suitable habitat may contained isolated populations.
Active Period: Mainly nocturnal, but can range from diurnal (in winter) to crepuscular, year-round.   More nocturnal than voles.
Diet: Green vegetation (especially grasses and clover), berries, a few invertebrates (slugs and snails),  and the subterranean fungus Endogone.  One SW VA study revealed sedges in summer and mosses in winter.
Home Range: 1/3 acre. (Nowak reports 0.2-0.5 acre, W/H says 0.02 – 0.13 acre, Mammals of Virginia reports 0.1 to 1 acre.  Wilson says 0.016 to 0.25 acre.  Whatever…)  
Social Structure: Quite sociable, occurring in colonies ranging from a few to several dozen.  The area around the nest is defended.  
Life Cycle: Two to four litters (March through October) averaging three (1-8) per litter per year.  Females are seasonally polyestrous and may have a postpartum estrus.  Females have litters every 67 days during the spring and summer.   Gestation period of 23 days.  Weaned in three weeks, becoming reproductively active in about eight weeks (Nowak says 5 weeks for males). Life span of about eight months with two years known in captivity.
Den/Nest: Nests (3 ½ - 6" diameter) concealed in hollows under sphagnum mounds, logs, or stumps or in grass tussocks, normally below the surface, occasionally on or just above the surface with 2-4 entrances.  Constructed of dead grasses and leaves, occasionally lined with fur.  Always well-concealed.   Often shares the same burrows with other small mammals.                 
Tracks: An underground tunnel system is common (6" depth), also constructs extensive surface runways, like voles.  In such highways, the grass is always cut and trimmed to keep the passages smooth. Known to cut grass stems one to two inches and deposit in piles along runways.
Scat: The use of the runways by meadow voles or southern bog lemmings can be determined by the color of scat; dark brown or black for voles versus bright green or yellowish of lemmings. 

Remarks: Bog lemmings are classified as voles.  They can be recognized by their very short tails. The meadow vole and southern bog lemming seem to share similar habitat, with the meadow vole being more competitive for limited habitat. In a Kentucky woodland clearing, the meadow vole is invading and replacing the southern bog lemming. Often found with red-backed voles, deer mice, prairie voles, moles, and various shrews; sharing the same burrows with them.

Their presence can be detected by neatly clipped piles of grass cuttings and tell-tale green droppings.

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Family Zapodidae - Jumping Mice

The jumping mice were originally described in the Dipodidae family, later placed in the their own family; Zapodidae.  But recent work (1990 and 1992), places them in the subfamily Zapodinae, in the family, Dipodidae, as indicated by Nowak's Walker's Mammals of the World .  However, Jones 1997 Checklist of North American Mammals still lists these two jumping mice in the Zapodidae family.  So be it.  The jumping mice are apparently more closely related to porcupine than to other mice.

The two species can occupy the same area where herbaceous ground cover is abundant along a stream leading into woods.  While the meadow jumping mouse may enter the woods in the absence of the woodland jumping mouse, the opposite is not likely to occur. 

The larger woodland jumping mouse can jump up to 12 feet; four times the length of the meadow jumping mouse.  

Two species, representing two genera are found in this Appalachian region.


MEADOW JUMPING MOUSE (Zapus hudsonius) (very large hindfoot; from the Hudson Bay)

Appalachian Region Distribution: Throughout.
Continental Range: From Alaska through Canada and Northeast/northcentral US.  Five eastern US subspecies recognized, with only one subspecies in the Appalachian region.  
Abundance: Uncommon. Tend to be localized in distribution and has annual fluctuations in populations.  Reportedly abundant on Assateague Island and certain areas proximate to the VA Blue Ridge.
Population Density: 2-8/ acre, up to 19/acre..
Size and Molt: Head and body 3 to 3 1/3 inches; ½ - 4/5 oz. Females are slightly larger than males. One molt.
Mammae: Four pair.
Habitat: The meadow jumping mouse prefers wet meadows, open grassy areas or dry fields with streams running through them. Often particularly abundant in patches of jewelweed (impatiens).  Where both the meadow and woodland jumping mice occur, the common name indicates their relative preferred habitats, although, in the absence of the woodland jumping mice, the meadow jumping mice will populate the woodland habitat. 
Active Period: Primarily nocturnal, although occasionally out during the day. These creatures are deep hibernators, sleeping about half of the year, accumulating body fat in fall. They arouse from their ground nests (which may be shared by several or singly) two to three feet underground every month or so to defecate and urinate. Males emerge in April, a week or so before the females, and reenter torpor in November.
Diet: Seeds predominate year-round.  Diet includes caterpillars and beetles in spring, grass and herb seeds in summer, along with berries, roots, nuts and invertebrates. Fungi (especially Endogone-up to 15% of it’s fall diet-found by smell) and fruit are favored in fall. The jumping mouse eats nearly half it’s weight per day. A hibernator, it does not cache food.
Home Range: ½ - 2 1/2 acres; a wide range, due to their wandering nature.  Males have a slightly larger home range than females.  
Social Structure: Solitary, except to hibernate, when several may share their warmth.  Generally, they are not antagonistic. 
Life Cycle: Breeding after spring emergence, they usually produce two or three litters (late May, July, and late August)  with an average of five (2-9) per litter per year. Altricial young, weaned between four and five weeks. Gestation period of 20 days.  No postpartum pregnancy. The first litter may mate by fall. Late litters often cannot accumulate enough fat to survive hibernation.  Life span of two to four years, five in captivity.
Nest: 4" summer nest on surface, or beneath brush, logs or stumps.  Winter nest (hibernaculum)  (4-6"  diameter), made of grass and leaves, is usually located in a burrow 2 -3 feet underground.
Tracks: These mice do not forage in runways or tunnels, rather they maneuver through the foliage.  Wilson says that, although they do not make their own runways, they use those made by other species, such as voles.

Remarks: The meadow and woodland jumping mice are the only true mammalian hibernators besides the woodchuck and bats, with a body temperature only a few degrees above freezing and its heart rate reduced to a few beats each minute.  Hibernation is triggered by means other than temperature.  It is believed that stored brown fat is one key.  Normally meadow jumping mice will accumulate a substantial layer of fat (about 0.2 oz - nearly double its normal weight) to sustain it through its lengthy hibernation.  About two thirds of the population does not survive the winter (normally young that haven’t accumulated adequate brown fat).  Hibernation lasts between late September/October through late April/May, longer or shorter, depending on latitude.  Males emerge first, with females emerging two weeks later, with mating immediately following.

The meadow jumping mouse has enlarged rear feet and small, weak front legs and an extremely long tail (4 -5"). It will take several hops of about a foot each when alarmed, although they are known to hop as far as three feet and as high as seven or eight feet. It is an excellent swimmer. 

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WOODLAND JUMPING MOUSE (Napaeozapus insignis) (woodland nymph with very large hind feet; insignia)

Appalachian Region Distribution: Throughout.
Continental Range: NE Canada and extending south along the Appalachian mountains.  Three subspecies are recognized in the eastern US, with two in the Appalachian region.
Abundance: Locally abundant in higher elevations within PA, MD, and VA; becoming restricted to suitable habitats above 2,800’ in NC.
Population Density: About 3/acre, with a range from 1-24/ acre.
Size and Molt: Head and body 3 3/5 to 4 inches; ¾ - 1 oz. Females slightly larger than males. One molt.
Mammae: Four pair.
Habitat: The woodland jumping mouse prefers cool, damp spruce or hemlock-hardwood mountain forests, especially moss-covered rocks along mountain streams.  Areas of dense herbaceous growth in moist habitats, or rhododendron thickets along streams, are preferred.  Has a much more restricted habitat than the meadow jumping mouse.  Can be found with the meadow jumping mice in prime habitat of jewelweed, where a stream runs from the woods into a field. Also, can be commonly found with southern red-backed voles and northern water shrew.
Active Period: Nocturnal. Profound hibernators, spending from September to May in deep torpor in underground moss/grass/leaf nests, awaking about every two weeks.  May put on one third its weight within two weeks in fall. Males emerge a week or two before females.  
Diet: They feed heavily on subterranean fungi (Endogone; up to a third of the diet of 103 sampled in New York and 40% of a Smokies study of 16 jumping mice.) and seeds (constituting 75% of the diet of another New York study – especially the bright turquoise-colored impatiens seeds). Also prefers insects.
Home Range: 1 - 8 acres, with males having a slightly larger range.  Ranges of both sexes overlap and are not antagonistic.  
Social Structure: Solitary
Life Cycle: Not having postpartum estrus, only two litters per season occur (June and August), with an average of five (2-7) per litter is common. Gestation period of 30 days (compared to only 20 of the meadow jumping mice), weaned in 30 - 35 days (Nowak says gestation period of 23 days).  If the second litter is late in the season, the young often will not be able to store enough fat to survive the winter hibernation (will accumulate 7 - 8 grams of fat). In fact, one study shows a 75% mortality in the second litter. Another study showed 75% mortality of all hibernating woodland jumping mice. May breed in first season or in the following year. By fall, 70% of the population will be young of the year.  For those who survive, life span of two to four years.
Dens/Nest: Dens in underground burrows that it either digs itself or takes over.  The entrance is covered during the day.  Summer 5 - 6" nest of dry grasses and leaves located under rotting logs or boulders, or in shallow underground burrows. Overwintering hibernaculum is underground, under logs or boulders, but not as deep as the meadow jumping mouse.
Tracks: Do not construct runways, but will dig it’s own burrows. Also will use existing burrows of other small rodents.

Remarks: Differs from the meadow jumping mouse by having a white tail tip.  Being much larger than meadow jumping mouse, can jump 9 to 12 feet. The hopping motion is called "saltatorial locomotion", practiced by kangaroos, wallabies, gerbils and kangaroo rats.  The singularly most profound hibernator of eastern mammals, the woodland jumping mice will spend up to six months in hibernation. From New York, south through the Alleghenies, the woodland jumping mice grades smaller and considerably darker. The scent glands impart a sort of pleasant nutty fragrance, unlike the pungent musk of the house mouse. 

The jumping mice are apparently more closely related to porcupine rather than to other mice.  

The jumping mice were originally described in the Dipodidae family, later placed in the their own family; Zapodidae.  But recent work (1990 and 1992), places them in the subfamily Zapodinae,  in the family Dipodidae. So says Nowak.  But I'm going with the Checklist, which is different, of course.  So they will go in their own Zapodidae family.  Why can't these guys get along?

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Family Erethizontidae - Porcupine

The porcupine is the only species of the 12 South American species (4 genera) that has made the journey north into North America.  Only the beaver is larger than the porcupine among rodents. 


COMMON PORCUPINE (Erethizon dorsatum) (irritate, animal; back)
 

ARTICLES

Appalachian Region Distribution: Common in northern Pennsylvania, but rare in this Appalachian region south of central PA.  The WV DNR reports that porcupines are found in the western Maryland counties of Allegheny and Garrett, but that no populations of porcupines now exists in West Virginia, despite isolated sightings in northeastern WV, possibly the result of individual porcupines that were released into the state.   However, the habitat is suitable for porcupine and, with the proximity of porcupines in Maryland, such future habitation is likely.  Early Europeans noted porcupine in VA, albeit notably scarce, even at that time.  Audubon and Bachman were unsuccessful in finding porcupine in VA in 1846.  It is now officially listed as extirpated in VA.  Porcupine records have been found from Indian sites dating from 6500 to 1000 BC in Tennessee and Alabama.
Continental Range: Throughout Canada and from Rockies west.)  Only the one subspecies (E. dorsatum dorsatum) exists in eastern US.
Abundance: Common in northern Pennsylvania, but rare in this Appalachian region south of central PA.
Population Density: Varies seasonally and in response to food supplies (and publication source).  Studies range from .03 to .4 per square mile in more northern habitat to 2-25 / square mile in north-central Pennsylvania.  Nowak and Wilson note a population cycle that peaks every 12 to 20 years, with studies supporting densities from 2 to 31 per square mile and 13-25/square mile.  W/H reports a density of from 3 to 14 per square mile in the east.  
Size and Molt: Head and body 17 to 31 inches; 10 - 15 pounds (males have been recorded at 37 ½ pounds). Males slightly heavier than females. Second only to the beaver in size for North American rodents. One molt.
Mammae: Two pair.
Habitat: These arboreal mammals prefer forests with both hardwood and softwood trees.  In the east, they prefer the mixed mesophytic forests and hemlock forests areas. Another favored tree species is the sweet birch.
Active Period: Primarily nocturnal, throughout the year, but is known to forage by day.  Juveniles and females will stay in their den for extended periods in severe cold spells.  Large males may remain in a tree fork for days; its dense coat and ability to drop its body temperature several degrees, providing adequate protection.
Diet: Herbivorous, as all rodents; but a strict vegetarian, one of only a few among the rodents.  Seasonally, there is a procession of foods, often determined by seasonally varied tannin levels.  In spring, porcupines feed on buds of sugar maple, basswood, and aspen.  Then, beech leaves, and later, ash leaves (along with various herbaceous plants).   Summer diet includes stems (especially aspen), roots, leaves, apples, berries, seeds, nuts, flowers and grass.  Preference for aquatic plants, with the porcupine eating from the shallow waters is well noted.  Late summer brought acorns and beechnuts (the ground under oaks are littered with the clipped twigs that porcupine drop before coming down to the ground to eat the acorns off the twigs).  Corn is also preferred.   Fall diet includes mast as well as corn crops.  Winter diet is primarily wood cambium (prefers conifers, specifically hemlock in the Appalachians). Variability in tannins among tree species causes porcupines to favor spruce, white pine, elm, basswood, beech, and sugar maple, while red maple and white ash are almost never eaten. Porcupine usually limits its feeding to two or three species of tree per winter.  Known to eat salt along roads (and anything that has been touched by sweating humans).  Plywood is a good source of salt.  Natural salt sources include yellow waterlilies, liverworts and fresh bone and antlers.  This need for salt is exhibited among all medium-sized mammals, who ingest huge amounts of potassium, but little sodium.  The imbalance between the two result in declining health; thus the need to ingest more sodium.  The hard to digest leaves and bark are broken down by enzymes secreted by bacteria found in a very long evolved intestine, large caecum, and protracted food-passage time.  These bacteria are found in a number of herbivores.  Because these enzymes act slowly, the porcupine has evolved this long digestive system.  
Home Range: Winter ranges are much smaller than summer ranges.  Nowak reports an Adirondack study finding 18.5 acres in winter and 162 acres in summer.  W/H reports 6 acres for winter range for both sexes, with 62 - 160 acres for a female's summer range and 75 - 370 acres for a males summer range.  In Pennsylvania, winter and summer home range is more stable; in the range of 6 to 36 acres.   Wilson reports 13 to 35 for winter and summer ranges respectively.  Winter ranges expand with low snow depth.  Females do not overlap, whereas males overlap extensively with one another and with several females.  
Social Structure: Porcupines are solitary except during breeding time during late fall and early winter and in winter denning concentrations.  Males are extremely aggressive towards other males during the breeding period.   Females are more territorial than males.  A dominance hierarchy determines male access to females.  Occasionally, in northern habitats, several (of either or both sexes) will den together in winter. Both males and females return to the same ranges year after year, although the male ranges may shift from one year to another. Unusual among mammals; among the juveniles, only the females disperse during the fall mating season.  Among adults, males will disperse.  Shedd relays a story about Robert Brander, a National Park Service ecologist, who has done extensive research on porcupines, documenting groups of porcupine (up to 12) gathering in an old clearing in mid-to-late summer.  It is believed that this was a social activity, occurring about a month before mating, with the members being quite vocal.
Life Cycle: The extremely long gestation period (205 to 216 days, with no delayed implantation or fertilization) enables only one litter of usually just one precocial per year, born in April through June (mating from September to December). See remarks below for mating rituals.  Females are polyestrous, recycling every 25-30 days, in heat for only 8 to 12 hours, and will aggressively attack non-attentive males during this short fertile period.  At birth, the quills are soft, hardening in about an hour. Young can climb trees within hours after birth. Porcupettes (I don’t make it up) wander off from the mother at about six months. Breeds generally at one and a half years (fall of the second year).  Wilson says females can breed at one year; males in two and a half.  Nowak reports sexual maturity is reached at approximately 2.5 years, although some males are capable of mating at 16 months.  Life span of 12-18 years (NAS says 7-8 years).
Dens/Nest: Multiple dens are kept in hollow logs, rock piles, caves, crevices and abandoned buildings. 70% of dens in the Catskills were in rock fissures at least 12' deep.  Doesn't actually make a nest, nor is denning material used.  In these narrow rock crevices, the animals sleep in a sitting position.  The only sign is the numerous scats produced in the order of 75 to 200, which are voided in the den, creating a deep deposition layer over time.  Is known to spend winter in a "station tree" of spruce or hemlock when dens are not available.  Dens are often used for many consecutive years.  However, multiple temporary shelters supplement the main habitation.  A change of winter dens occurs every three weeks or so (for unknown reasons).  One abandoned house in New Hampshire provided dens for six porcupines; two in the chimney and one in each of the four bake ovens!
Tracks: Five rear toes (1 1/2" w x 3 1/2" l) and four front toes (1 1/4"w x 3" l).  (These measurements include the claws.)  6" stride and 8" straddle.  The porcupine makes a runway through vegetation and may wear a distinct path from the den to the feeding area.
Scat: Brown, crescent-shaped droppings, often in large piles inside and outside the den entrance.
Can be variable, often like deer.

Remarks: The pelt of the porcupine gives a black and white appearance, similar to the skunk; a warning sign to potential predators.  Porcupines also emit a unique, pungent odor, which can cause the eyes to water and the nose to run. 

In addition to the normal underfur and long guard hair, porcupine are afforded protection by 30,000 very long modified hairs, known as quills.  Like the skunk, the porcupine evolved natural protective qualities that enable both these creatures to adopt a slow, deliberate life style.   Porcupine cannot shoot quills against predators, but the quills easily come out of the porcupine's body.  The hollow quills have scales along the tips with raised edges pointing toward the rear, which work like barbs, piercing into predator flesh at a rate of 1" a day. Quills have been known to work completely through an animals’ body, rarely puncturing a vital organ, killing the animal.  Cutting off the ends will decrease this rate (Shedd says cutting off the ends will make matters worse, since it leaves less quill to grip with pliers, and may splinter the quill as well). The quills are found in highest density on its back and the upper surface of it's tail and longest on its upper shoulders.  In addition, the porcupine can produce a strong, pungent odor, which can cause eyes and nose to water.

Porcupine are preyed upon by fisher, who especially favor porcupine.  Fisher attack the porcupine by biting the face numerous times, weakening the animal to the point that the fisher can roll the prey over and attack the vulnerable belly.  Fishers reintroduced into the Catskills and the Ottawa National Forest of Michigan have decimated the porcupine populations.  Other predators include wolverine, cougar, great horned owls and bobcat.  Porcupines have a fondness for the minerals found in antlers (and the salt from roads - leading to frequent road kills).

One article basically says,  "If you want to be desirable mate for a female porcupine, first you have to perform a "three-legged dance" while whining a special serenade. It helps if you can hold your genitals with your forepaw (or rub them with a stick) while dancing. Finally, you shower your intended with urine. At which point you can very carefully mount your mate in the traditional manner. "

Many skeletal remains show signs of healed fractures, presumably the result of falls from broken thin tree limbs (35% of 45 specimens showed healed fractures in one study). 

In addition to numerous fatalities from the quills reported to dogs, owls, cattle, and horse, one human fatality has been recorded as the indirect result of eating a porcupine meat sandwich containing a quill (OW!!!). 

 

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