Mammals at the Cofrin Center for Biodiversity

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Species List and Descriptions

The following is a list of mammals that can be found in the Cofrin Arboretum.

ORDER DIDELPHIMORPHIA: New World Opossums

This order is characterized by its mode of reproduction. The pouch found in the mid section of the female opossum, houses the the young. The young are not quite developed when they crawl through the fur of the mother to attach to a nipple, where they will stay for several week to continue development. There is only one family found in this order, Didelphidae.

Opossums (family Didelphidae)

Most of the species in this family are from tropical climates except for the Virginia Opossum. This species has gradually moved farther to the north. They have five digits on each foot, with one opposable toe. Most of the species in this family are arboreal and omnivorous.

Virginia Opossum (Didelphis virginiana) This species has become a very common species in this region. It is recognized by its wooly fur, short legs, and long, scaly tail. This adult size of this species is about the size of a house cat. This species is generally found in woody areas near some water system. This wood include steams, ponds, drainage ditches, and swamps. yThis species is a solitary wanderer, never staying in the same den site for a long time. Its home range can be very tough to be defined. A common practice of the opossum is "playing dead" in order to escape a predator. It will lay on its side with its mouth open and continually drooling in order to puzzle the attacker. It can remain in this state for up to six hours.

ORDER INSECTIVORA: Shrews and Moles

The mammals that are contained within this order have a few distinguishable traits and characteristics.These characteristics include a long pointed snout, minute eyes and ears, five claws on each foot, and a very soft and dense fur. They are a very diverse group that populate a variety of different niches and habitats. The main food supply for these mammals is insects, but will resort to vegetation occasionally. There are two different families found within the arboretum, Soricidae and Talpidae.

Shrews (family Soricidae)

These are the smallest mammals. They have reduced ears and very minute eyes. In some species, the eyes will not be used.Some have a heightened sense of smell and well-developed auditory system.

Masked shrew (Sorex cinereus) The most common and abundant long-tailed shrew in the area although it is rarely seen. A voracious feeder, it is active day and night. It is slightly bi-colored with a grayish brown back and lighter colored belly with a long tail. This species can be found in numerous habitats and forest types. Some include overgrown fields and alder thickets but it prefers moist areas with thick areas of plant cover and thick leaf litter. It searches for food in pathways below the leaf litter or in mole tunnels and along fallen logs. When it is not feeding, it is resting in nest of grass/leaves in half rotted logs. It is the most abundant long-tailed shrew within the arboretum and can be found throughout.

Short-tailed shrew (Blarina brevicauda) This species is the largest shrew found in North America. It is recognized by its soft, dense gray fur and short tail. It is very abundant in a variety of habitats. These would include disturbed and undisturbed areas, deciduous and coniferous forests, grasslands, and moist areas with thick vegetative cover. It will travel below the leaf litter or use subterranean tunnels while foraging for food. One distinctive characteristic of this species is that it produces a toxin in its salivary glands. This poison is used to paralyze and kill its prey.

Moles (family Talpidae)

These subterranean species have very unique features.They have developed huge paddle-liked forefeet that aide in digging tunnels. They lack external ears and have very poor vision. Their hair lays down in any direction, allowing them easier movement in the tunnels. Signs of these species are ridges and molehills found in the soil.

Star-nosed mole (Condylura cristata) This is a very distinctive mole that is recognized by its 22 fleshy projections from the tip of its nose. These projections act as a sensory device since this species can not see in the dark tunnels. It prefers a moist, saturated soil. This species is active year round, digging tunnels in the softest soil in winter or in the snow. It has dark fur and a long tail. In winter, the tail is used for fat storage. Its basic diet consists of earthworms.

ORDER CHIROPTERA:Bats

Bats are the only mammals that are able to perform true flight. They have developed a thin membrane of skin that extends from the ankle to the shoulder. Their finger and hand bones, except for the thumb, act as a support to this membrane. Also, many bats rely on their keen sense of hearing. They will rely on echolocation in order to aide their nocturnal flights. This is where a sound is emitted and reflected back to the source in order to identify structures.

Plain-nosed bats (family Vespertilionidae)

The species in this family have three common features.They will enter a state of torpor, hibernate, and delayed fertilization.These traits help this family to conserve energy and produce offspring at times of plentiful food. This family of bats will usually consume insects, seeds, and nectar from plants. This family also has a leaf-like formation in its ear to aide in the echolocation called a tragus.

Little brown bat (Myotis lucifugus) This species is a medium sized bat that has an olive to brown fur with large ears. This bat is active at all times of the night, but feeding reaches its peak a couple hours after sunset. When this species enters its state of rest during the day, it can be found in hollowed trees, underneath loose bark, or any dark, undisturbed areas.This bat mainly feeds on insects such as mayflies and chironmids.

ORDER LAGOMORPHA: Rabbits, Hares, and Allies

These mammals can be found on all continents, only after being introduced to Australia by humans. There are two families within this order: the Leporidae and Ochotonidae. The Ochotonidae is found in Asia and the mountainous regions of North America. The Leporidae is the only family found in Wisconsin. Lagomorphs have two pairs of upper incisors with the second pair directly behind the first. They have a very thin skin and hair covering the soles of their feet.

Hares and Rabbits (family Leporidae)

This family is recognized by its large hind feet, long ears, and bushy tail.Hares generally have longer ears and larger feet than a rabbit.

Eastern cottontail (Sylvilagus floridanus) A very abundant species on campus in close relation to herbaceous vegetation and shelter, such as thickets and brush piles. This species has a grayish brown fur with a rusty color on the back neck (or nape). Similar to rodents, this species dentition has a diastema or gap between its incisors and molars. This species is active at night but can be frequently seen at dusk and dawn. It nests in depressions in the ground or an abandoned woodchuck den. Females will mate within a few hours after giving birth because not many of this species will survive past one year

ORDER RODENTIA: Squirrels, moles, voles rats, mice

Gnawing mammals This is the most successful group of mammals containing the largest number of species.Squirrels, mice, rats, and voles are contained within this order. These species have an adaptation in their dental formula. There is a diastema or gap between their incisors and molars. For the most part, these species are terrestrial. However, some have adapted to a different lifestyles. Some are arboreal like the red squirrel, some are fossorial like the thirteen-lined ground squirrel, and some are volant like the flying squirrel.

Squirrels (family Sciuridae)

The species within this family are characterized by their thickly haired tails. The species with the long bushy tails are arboreal, living mainly in the trees above the ground. The tails are used for a balancing mechanism. The ground-dwelling squirrels will have shorter, thinner tail.

Eastern chipmunk (Tamias striatus) This species has a reddish brown fur with a white stripe bordered by two black stripes down its back that end at the rump. It prefers an open deciduous woodlands with stumps, logs, and thick cover, forest edges, and houses. This species will burrow tunnels for nesting areas and for food storage. Inside its mouth, between its lips and molars, is a cheek pouch that enables the chipmunk to cache food and bring it back to the burrow. It does not hibernate, but to save energy it will be inactive for periods of time, or torpor.

Woodchuck (Marmota monax) This is the biggest squirrel in the great lakes region. This solitary species has a dark brown fur with short legs and small ears. Its legs are very powerful, allowing it to dig extremely well. Large mounds of dirt in front of a burrow hole is good indication of their presence although rabbits, opossum, and fox will take over an abandoned hole. Woodchucks prefer pastures, open forest habitats, and small wood lots. This species will enter hibernation from October to March/April.

Thirteen-lined ground squirrel (Spermophilus tridecemlineatus) This species is found in open short grass pastures, manicured lawns, dry meadows, or along roadsides. It has a slender body with a brownish/gray coat that has thirteen alternating brown and white stripes running down its back. It has short ears and large feet which enable it to tunnel below the surface. It is mostly a diurnal species, especially on warm days. It has cheek pouches that allows it to carry food to its burrow. It hibernates from September to March/April. This species also has a high mortality which is why their will be 8-9 young in their litter.

Gray squirrel (Sciurus carolinensis) This common species is recognized by its gray fur with silver tipped hairs, large bushy tail, and pale underside. There is a black phase with this species that is seen in the Gray Squirrel (Photo by Dr. Lloyd Glenn Ingles, California Academy of Sciences) northern reaches of their range. It is often seen in mixed forests, especially with oak and hickory trees. It will nest in tree cavities of older trees and snags in the spring, then will move to a leaf nest later in the year. It is active year round, searching for food it stored in the ground. This species will recover about 85% of the nut caches it stored in the ground because it can smell the nut, even through snow. Recovery of its food has nothing to do with memory.

Fox squirrel (Sciurus niger) This is the largest tree squirrel in the area. This species has a large bushy tail and a fur with orange tipped hairs. It is very similar to a gray squirrel except that it is a little larger. It prefers deciduous trees that lack under-story bushes, often found in park settings with oak and hickory trees. It is active during the day on the ground. It is an omnivorous feeder, feasting on fruits, nuts, buds, caterpillars, and eggs of birds on occasion.

Red squirrel (Tamiasciurus hudsonicus) This small tree squirrel is common in forests with conifers present, although it can be found in a deciduous forest with a few conifers. It has a rusty to grayish red color with a pale gray underside. This species is active year round. In the winter it has black ear tufts. It will also tunnel underneath the snow in search of food and for protection. It will nest in tree cavities as well as fallen logs or on the ground. It is an opportunistic feeder with a diet of cones, seeds, nuts, maple sugar, and bird eggs.

Southern flying squirrel (Glaucomys volans) This completely nocturnal species is active year round in various open deciduous forests. It is a very small squirrel that has large eyes, flattened tail, silky gray/brown coat with white underside fur, and an extra fold of skin that assists in gliding. It will have two nest sights in tree cavities or abandoned woodpecker nests. One is for rest while the other is used for feeding. This species will venture to the ground although it is very clumsy there. While flying, it will use its tail to change directions. Once it lands on its destination tree, it will race to the other side of the tree to avoid detection by a predator.

Rats, Mice, Lemmings, and Voles (family Muridae)

This is the largest family of mammals. Most of the species within this family are terrestrial or somewhat fossorial. Typical characteristics of this family include a long tail with large ears and eyes. The species in this family tend to have an herbivorous or granivorous diet.

White-footed mouse (Peromyscus leucopus) This species is common in a variety of habitats including deciduous woodlands, cultivated areas, and prairies. It is a nocturnal species that is active year round, only entering a state of torpor for short periods. It is recognized by its large black eyes, black ears, bicolored tail, and grayish brown fur. The tail is a dark brown color on top that gradually changes to a pale color below. Because this mouse is semi-arboreal, it will use its tail for balance. This species is omnivorous and included in its diet is seeds, grubs, caterpillars, and beetles. Mainly a solitary mammal, but will tolerate others in winter times.

Meadow vole (Microtus pennsylvanicus) This species has variable fur colors ranging from brown to black. It is sometimes confused with the southern red-backed vole, however, it does not have a rusty red colored back. Its ears are small, often hidden by its fur. This species can be found in moist areas including grassy fields, marshes, bogs, and sometimes in woodlands. It is active mostly at dawn or dusk, although more at night. It will use its runways to search for its food sources of sedges, fungus, and caterpillars.

Muskrat (Ondatra zibeticus) This is a large rodent that is common near water sources, marshes, and wetlands. It has a soft, glossy brown fur with a scaly tail, small eyes and ears. Its hind feet are partially webbed to assist in swimming. It is regularly seen any time of the day. It houses or dens are built out of aquatic vegetation like cattails and sedges, unlike a beaver which will use more woody material. The muskrat will also burrow into bank edges for den sites. It normally feeds on the basal parts of aquatic vegetation as well as roots. However, it will also feed on crayfish, frogs, mussels, and an occasional small fish.

House mouse (Mus musculus) This common species is usually found in close proximity to humans, especially near buildings, cultivated fields, fence rows, and other human structures. This species was introduced from Europe and has a high density due to its high reproduction. This species is recognized by its grayish fur, scaly tail, and bulging eyes. This species is an omnivorous scavenger, usually feeding on seeds, larvae, and waste. This species is also known as a vector for many diseases, causing it to be a nuisance to humans.

Norway rat (Rattus norvegicus) This brownish gray species with long scaly tail is an introduced species from Europe. It will usually be found near cultivated fields and man-made structures such as barns, buildings, and houses. It is very colonial, occurring with others of its species. It is an opportunistic feeder, feasting on anything that is available. This species has also been known as a vector for many diseases that can be harmful to humans.

Jumping mice (family Dipodidae)

This family is characterized by its saltorial locomotion. They are able to bound and leap great distances when disturbed. They are also noted for their very long tail, and large hind feet. The bi-colored tail is used for balance when it is leaping away from a predator. Most of the species in this family are true hibernators.

Meadow jumping mouse (Zapus hudsonicus) This brightly colored species is recognized by its large hind feet and its long tail with a white tip. It has a brownish colored back with orange tinted sides. This species is found in moist coniferous and deciduous forests that has dense under story of ferns, shrubs, and other plants. It is normally not to far from a water source. Although it walks most of the time when it is searching for food, it is an excellent jumper, able to jump 6 to 8 feet when being chased by a predator. It will feed on seeds, caterpillars, subterranean fungus, and beetles during nighttime.

ORDER CARNIVORA: Carnivores

The species found in this order are primarily known as flesh eaters. Others in this order are opportunistic feeders, feeding on whatever is available at the time. This order of mammals have a very ferocious appearance. There are three families that appear in the northeastern Wisconsin area, the Canidae (dogs), the Procyonidae (raccoons), and the Mustelidae (weasels).

Dogs, foxes, and Wolves (family Canidae)

This family has a dog-like appearance. Most of the species in this family have slender legs, bushy tails, long nuzzle, and erect ears. Also common in this family is that there are four toes on the hind feet and five toes on the front feet.

Coyote (Canis latrans) This species has a light brown/gray fur with tints of yellow. It resembles a medium sized dog, larger than a fox but smaller than a coyote. It has a bushy tail and erect ears. It is commonly found in deciduous forests, forest borders, other hardwood areas. This species is commonly found out at night but also during the day, especially during the summer. Its prey normally consists of small mammals and birds. The coyote's home range will depend on the availability of food.

Red Fox (Photo by Gerald & Buff Corsi, California Academy of Sciences) Red fox (Vulpes vulpes) This fox has a soft reddish to yellow/red fur coat with white undersides. It also has a very bushy tail with scarce black hairs and a white tip. It can be found in a variety of habitats including woodlands, pastures, meadows, and lowlands near water. It is also adapting to urban settings such as city parks. This species is an opportunistic feeder, feeding on insects, small mammals, birds, and berries. They will often den in a modified woodchuck den found on a hillside. This species has shorter legs and a more stout body than a gray fox.

Gray fox (Urocyon cinereoargenteus) This fox gets its name from its gray fur with black and white tips of hair. It has a smaller body than the red fox, but has longer legs. This species can be found in brushlands, forests, and in areas closely associated with water. It is seldom found in cultivated fields and meadows. It will den in brush piles, rock crevaces, or modified woodchuck dens. It genrally feeds on small mammals, birds, and some plant material in late summer such as corn, nuts, and apples.

Raccoon and their allies (family Procyonidae)

There is only one species from this family that inhabits the Great Lakes basin. This family are generally small to medium sized carnivores. All generally have some sort of facial markings as well as an alternating colored tail.

Raccoon (Procyon lotor) This common species is recognized by its black mask across its eyes and striped tail. This species has a stout body. The raccoon dens in hollow trees. This nocturnal species is very intelligent and can survive in a variety of habitats. This species is closely associated with habitats with shorelines. The omnivorous raccoon will follow along the stream banks in search of food such as insects, crayfish, and frogs. The adults have been known to wash their food before eating it.

Weasels and their allies (family Mustelidae)

Most species in this family are characterized by their long, muscular body's with short legs. They are known for there furs and for being a very aggressive mammal. They get their family name from an anal scent gland.

Fisher (Martes pennanti) This large weasel has a slender body with dark brown fur. This solitary mammal was restocked into parts of Wisconsin in this century. This species prefers dense coniferous and deciduous forests. Even though it will den in hollow trees and is a very good climber, it will usually be found on the ground in search of food such as small mammals and birds.

Ermine (Mustela erminea) This weasel has a long slender body with a long neck, short tail and small head. It has two color phases, one in the winter and the other in the summer. Its summer fur is a brown fur along its back with white undersides and its winter phase color is completely white except for a black tipped tail. It is commonly found in heavily wooded areas and brushlands that are not far from water. This ferocious mammal feeds on small mammals and birds it hunts during the night. It will generally den in hollow logs, abandoned rodent holes, and underneath rocks.

Least weasel (Mustela nivalis) This is the smallest carnivore in the world. It has a very thin, slender body with a rich brown fur that has white on the underside. This species will feed on small mammals such as mice, voles, and shrews. It is active at all times of the day, resting for short periods in vegetative nests or rodents burrows. A very quick moving species, prey are attacked and repeatedly bitten around the head and neck. It can be found in mature forests, open fields, pastures, and open woodlots.

Mink (Musteal vison) This species has a rich, glossy, dark brown fur. It is generally found in forested areas that are close to water, although they have been found great distances from any kind of water source. This good climber is active at night, generally near dusk and dawn, bounding quickly in seach of food. Its diet consists of muskrats, waterfowl, and fish. Its nest is also very close to water. It is an underground burrow that has openings near the water's edge.

Badger (Taxidea taxus) This species is a very ferocious weasel. It is about the size of a medium dog with very short legs. Its dorsal fur is very long, giving it a shaggy appearance. It has a white stripe running down the middle of its face from the nose to the shoulder. It also has extremely large claws on its fore feet, allowing it build its enormous burrows in rocky and sandy soils. It is commonly found in open fields, pastures, and fence rows near its prey of gophers and ground squirrels. This species is very aggressive and extremely dangerous when cornered.

Striped skunk (Mephitis mephitis) This species is the size of a house cat and is very hard to be mistaken for anything else. The black fur with two white stripes running down the back give this species its recognizable features. The fur color as well as a raised tail act as a warning to other species. It can be found in sparse woods, open fields, pastures, and stream borders. This carnivore will prey on anything available dependant on the season. Its diet consists of insects, fruits, small mammals, and vegetable matter. When threatened, it will turn its body into a U shape, facing the intruder with its face and tail, warning of an impending dousage.

River otter (Lutra canadensis) This weasel has adapted to an aquatic lifestyle. Its long slender body with sleek fur, tail, and webbed feet aide in this type of living. It has a rich brown fur that has silvery colorings around the throat. It is commonly found on and around the shores of lakes, stream, and rivers. Its basic diet consists of frogs, invertebrates, fish, and crayfish. They inhabit underground dens that have access to water below the surface. These are usually abandoned muskrat or beaver dens. They are primarily active at night and is adapt at sliding across the surface into the water.

ORDER ARTIODACTYLA: Even-toed ungulates

The species in this order are grouped together because of they possess hooves instead of nails or claws. They also only have two or four functional toes which is due to an evolutionary adaptation which allows them to run faster with longer strides. Another characteristic that they share is that they have three or four chambered stomachs. Because the species in this order eat low quality foods such as grasses and twigs, they possess a rumen which assists in the chemical break down of these foods. The food is regurgitated and chewed again to digest completely the food.

Deer (family Cervidae)

This family are recognized by long face, long legs, even toed hooves, and antlers. The antlers are bony out-growths that are used for sexual advertisement and protection. They are replaced annually with the size showing maturity of the individual. They are usually found on males, except in caribou, where both the female and male can develop antlers.

White-tailed deer (Odocoileus virginanus) A very common species in woodlands, brushy areas, fields, coniferous forests, aspen, and meadows. There is a color difference as the seasons change, a rusty red/tan color in summer to a brown and grayish color for winter. Their white tail is used as a warning when it is raised. It is normally seen in the hours of sunrise and sunset, although it is active in secluded areas at all times of the day. Deer browse can be seen on grasses, aspen, hemlock, and flowering buds of other woody species.

Other Mammals ofthe Cofrin Arboretum

The following is a list of species that have never been observed in the Cofrin Arboretum, but the climate and habitat are appropriate and these species may have lived there or in the area in the past.

Arctic Shrew (Sorex arcticus)
Pygmy Shrew (Sorex hoyi)
Water Shrew (Sorex palustris)
Long-Eared Bat (Myotis septentrionalis)
Red Bat (Lasiurus borealis)
Hoary Bat (Lasiurus cinereus)
Silver-Haired Bat (Lasionycteris noctivagans)
Big Brown Bat (Eptesicus fuscus)
Snowshoe Hare (Lepus americanus)
Northern Flying Squirrel (Glaucomys sabrinus)
Beaver (Castor canadensis)
Deer Mouse (Peromyscus maniculates)
Common Porcupine (Erithizon dorsatum)
Bear (Ursa americanus)

Photos courtesy of California Academy of Sciences/Manzanita Project and CalPhotos.

Biodiversity Topics: Introduction . Plants . Animals . Mammals . Birds . Reptiles & Amphibians . Arthropods . Spiders . Insects