List of mammals of Connecticut

Species

• Virginia opossum — common in wooded areas, farmland, drier areas of wetlands, rural areas and in some other habitats in the state; came to Connecticut from the south in the early 20th century, a movement likely helped by its attraction to human-created food sources such as crops and trash, although it eats just about anything, including carrion. Many are run over on Connecticut roads.

  Shrews and moles

• Northern short-tailed shrew — very common in leafy or grassy ground
• Smoky shrew — common, especially in moist, shady spots
• Masked shrew — plentiful in the state, especially in moist, shady spots.
• Water shrew — uncommon; found near water
• Least shrew — rare in Connecticut, where the species reaches its eastern limit and close to its northern limit ; in this state, only found in coastal areas with high beach dunes and neighboring brackish marshes; all other shrews in the state have much longer tails. As of late 2007, the species was the only mammal listed on the Connecticut endangered species list, and it was the first mammal ever put on the list. The greatest threat facing least shrews in the state is land development along the coast, which limits the land available for the species and isolates breeding populations. Other threats are pesticides and pollutants contaminating food and habitat. The animal was first identified in Darien, Connecticut, in 1840 by Reverend James H. Linsley, but not seen again for 100 years. In 1941, George Goodwin, assistant curator of mammals at the American Museum of Natural History, in New York City, found one in Westbrook at the edge of a saltgrass meadow. The animal again went without documented sightings until it was found in 1989 in coastal Middlesex County in 1989. As of 2007, this is the only documented Connecticut location of the species.

• Eastern mole — common in the state; usually found in fields, lawns and wooded areas that aren't too wet; much less prevalent in higher elevations in the northern parts of the state
• Star-nosed mole — common in wet or moist soils near water, less common in upland areas that are moist; apparently active at ground level during the night
• Hairy-tailed mole — somewhat common in well-drained areas in northwestern part of the state

  Bats

• Little brown bat — common and widespread in the state; this and the big brown bat are the two most common bat species in the state
• Big brown bat — winters in the state, often hibernating in buildings, occasionally caves; a bat seen in winter is probably this species; in summer it often roosts in attics; it breeds in the state.

• Silver-haired bat — uncommon; usually seen near water; listed as a Connecticut species of special concern
• Red bat — usually found at lower elevations; seldom seen and listed as a Connecticut species of special concern
• Hoary bat — seldom seen and listed as a Connecticut species of special concern
• Northern long-eared myotis or long-eared bat

• Northern long-eared myotis
• Little brown bat
• Eastern small-footed bat — believed to have been extirpated in the state, and it was probably always scarce; no confirmed sightings have been recorded in the state for several decades; listed by the state as a "species of special concern"
• Indiana bat — in the several decades up to 2004, only one was ever found in the state; the bat is on both state and federal lists of endangered species
• Tricolored bat

  Rabbits and hares

• Eastern cottontail — introduced to New England in the late 1800s and has expanded its range at the expense of the native New England cottontail. The species originally came from the south. By the 1930s, New England cottontails were still considered more numerous than the eastern cottontail, but both species were declining as farms reverted to forests; found in shrubby and open areas, often in disturbed areas. Hammonasset Beach State Park has many of them; in the early evening, 30 to 40 can be found along the entrance road.
• New England cottontail — native but now relatively uncommon since in most places the eastern cottontail has replaced it; it appears to be more common in the west-central and southeastern parts of the state; generally found in shrubby wetlands and forests with dense plant life near the ground. Another possible reason for the decline of this species could be the loss of areas with suitable ground cover, which protects the animals from predators. Loss of farmland to forests is thought to have reduced the population since the 1930s, when New England cottontails were still thought to outnumber eastern cottontails.
• Snowshoe hare — common in the northern part of the state, usually where there are dense thickets; the population in Connecticut doesn't soar cyclically, as the species does farther north

  Rodents

• Groundhog, woodchuck or whistle pig — scarce when Europeans first came to North America, but they have thrived since then.
• Eastern gray squirrel — the most frequently seen mammal in Connecticut and the largest squirrel found in the state. Acorn production can fluctuate greatly from year to year, affecting the squirrel population. Historically, there have been reports of large migrations of squirrels, including one in 1933 involving at least 1,000 gray squirrels swimming across the Connecticut River between Hartford and Essex. Limited food supply probably causes these migrations, although the exact causes are unknown. In Stratford, white squirrels, a local variant of the species, had been seen for years as of 2010 in different sections of town. Many had some light gray or reddish color and black eyes, indicating they were not albinos.
• American red squirrel — found usually in spots with stands of mature conifers, including white pine or eastern hemlock, but even in those areas there are usually fewer than one individual per acre;
• Southern flying squirrel — common where there are nut trees and available nesting cavities, often near streams and wetlands
• Northern flying squirrel — present in just a few areas in northern Connecticut; usually old-growth forests
• Eastern chipmunk — common in woods
• Fox squirrel - Introduced in the 1900s. Now is absent from the state.

• North American beaver — found in small and large low-gradient streams, including tidal parts of the lower Connecticut River, as well as lakes and other water that is both permanently present and deep enough not to freeze all the way to the bottom in winter; most common where its favorite food plants are ; they not only dam up smaller streams but can be found in rivers too big to be dammed; common in the state before the arrival of Europeans; trapping led to their extirpation in the state by about 1842, then reintroduced, first in Union in 1914, and at other times up to the 1950s. They thrived so well that in 1961, the first state-regulated trapping season began in order to manage their numbers in light of growing nuissance complaints; the population is large enough now to be trapped, and generally 500 to 1,000 are trapped each year; in the 2001–2002 season a record 1,224 were trapped; in 2000 it was estimated there were between 5,000 and 8,000 beavers in the state; they can annoy homeowners with their tree cutting and flooding from their dams ; in Connecticut, people must get a permit from their town wetlands commission before altering beaver dams to prevent or reduce flooding

• White-footed mouse — common in woods and especially along forest edges; particularly where there are plenty of nuts or large seeds;
• Deer mouse — found in the northern part of the state
• Allegheny woodrat — once existed at one site in western part of the state but now extirpated; it has also disappeared from many areas in the Northeastern United States
• Southern red-backed vole — common in the state, especially in forests with plenty of ground cover such as logs, rocks or old stone walls
• Meadow vole — often found in abundance in pastures, meadows, marshes or wherever there is thick, unmowed grasses or sedges
• Woodland vole — common in the state; found mostly in partly wooded uplands
• Muskrat — common in ponds, lakes, slow-moviing streams, canals, swamps and marshes
• Southern bog lemming — usually lives along the edges of bogs, but also sometimes found in shady uplands with thick humus soil
• House mouse — common in cities and farms, associated with people and farmland; comes from Europe
• Norway rat — common wherever it can find food, such as at farms, in cities, near garbage dumps or waterfront areas; comes from Europe; barn owls near the New Haven landfill often feed on them

• Meadow jumping mouse — rather common in Connecticut in areas with thick vegetation, including meadows but also old fields, forest edges, often near water
• Woodland jumping mouse — rather common in Connecticut in moist, forested areas or spots with thick shrubs, usually along streams

• North American porcupine — uncommon in forested areas in the northern part of the state; usually found in mixed forests including eastern hemlock. Porcupines are most common in northern Litchfield County, especially the towns of Hartland, Colebrook, and Norfolk. It is not uncommon to see them as roadkill along Route 8 through the towns of Winchester and Colebrook.

  Carnivorans

Dogs, wolves, coyotes, and foxes (Order [Carnivora], Family [Canidae])

• Coyote — first spotted in Connecticut in the mid-1950s, with the first 10 years of reports only in the northwestern part of the state, although they have since spread across the entire state. The state Department of Environmental Protection estimates there are 2,000 to 4,000 in the state as of 2007. Anecdotal evidence suggested the population at that time was growing DEP officials said.
• Gray wolf — extirpated in Connecticut in the 19th century; deliberately killed by early settlers, but the population also was hurt by the reduction of its food supply ; some taxonomists say the wolf that used to inhabit Connecticut was actually the eastern Canadian wolf
• Red fox — a native species to New England, but it probably interbred with red foxes introduced from Europe; the hybrid is now thought to be the only type in Connecticut; tends to be absent where coyotes are regularly present; prefers habitats with a mixture of fields and forest edges
• Gray fox — fairly common, but less so than the red fox; it tends to inhabit denser forests than the red fox; the population has been growing for the past century with reforestation in the state the main cause; in the Connecticut, the normal home range for a fox is about two to four square miles, but abundance or lack of food supplies can change that

  Bears (Order [Carnivora], Family [Ursidae])

• Black bear — rare in most of the state, but fairly common in Litchfield and Hartford counties in the northwestern and north central parts of the state; bears have expanded from their core habitat in the state's northwestern hills, and they have been seen for several years as far south as Greenwich, in the southwestern corner of the state; in 2002 the population was probably above 100 and growing, Geoffrey Hammerson wrote in Connecticut Wildlife: Biodiversity, Natural History, and Conservation, but state wildlife biologists for the Connecticut Department of Environmental Protection estimated in 2008 that there were more than 300 in the state, with the population growing by about 15 to 20 percent a year. DEP annual bear surveys began in 2001. They were extirpated from the state by 1840, but the DEP had hard evidence of a resident population in the 1980s. Since then sightings have increased dramatically. In 1997, the DEP received about 100 calls reporting bear sightings; in 2007, it received 2,000. The state DEP encourages bear reports on its Web site. Reforestation of the state was the major factor allowing for the reintroduction and expansion of the bear population, and that expansion is expected to continue. State policy is not to remove bears unless the area is urban; the agency seldom relocates bears and only does so within Connecticut, since no other state will accept them. Bears that persistently kill livestock, enter buildings or demonstrate similarly problematic behavior may be killed under state policy. There is no hunting season for bears in the state. The DEP asks people who see bears in Connecticut to do the following:
• *"Enjoy it from a distance."
• *"Never attempt to feed or attract bears."
• *"Report bear sightings to the Wildlife Division, at 675-8130."

  Raccoons and relatives (Order [Carnivora], Family [Procyonidae])

• Raccoon — found near lakes, ponds, marshes and streams; a rabies epidemic devastated the population in the state in the early 1990s, killing as much as 75 percent of the population; raccoon rabies still remains in Connecticut, with about 200 cases a year as of 2004, and including skunk and cat infections as well as raccoons; rabies cases should be reported to police or animal control officials

  Weasels and otters (Order [Carnivora], Family [Mustelidae])

• River otter — previously scarce, but now somewhat common in the state; found in many lakes and large ponds
• Mink — rather common in streams, ponds, lakes and marshes; large minks are now extinct but may have lived along the coast of the state in the 19th century
• Long-tailed weasel — Like the ermine, fairly common in woods and thickets and near stone walls; especially near rivers and streams
• Ermine or short-tailed weasel — Like the long-tailed weasel, fairly common in woods and thickets and near stone walls; especially near rivers and streams
• American marten — one recent road-kill in New Hartford, Connecticut was the first certain evidence that the species occurs in Connecticut
• Fisher — Fishers live in large, thickly wooded forests; the species was extirpated from southern New England when forests were cleared and was absent for more than a century. From 1989 to 1991, they were reintroduced from New Hampshire and by 2004 were established in northern Connecticut. Population density is normally no more than one fisher per several hundred acres.

  Skunks (Order [Carnivora], Family [Mephitidae])

• Striped skunk — common in the state and in various habitats

  Cats (Order [Carnivora], Family [Felidae])

• Bobcat — They favor thickets and patchy woods in the least-developed areas of the state, especially in the northwest highlands of Connecticut; they normally are scarce where coyotes are more prevalent. It is unknown whether or not the burgeoning coyote population has resulted in a decline in bobcats, however. Unlike coyotes, bobcats do not adapt well to nearby human populations; they prefer immature forests with a thick understory. In the 1970s the price of bobcat pelts rose so much that state officials became concerned they would be overharvested and reclassified the bobcat as a protected furbearer, with no hunting or trapping seasons. A rabid bobcat attacked a man in Plainville in 2003, but the incident is regarded as a rare, freak occurrence.
• Canada lynx — apparently never a permanent resident of the state, but historically it may have been in the state.
• Cougar or mountain lion — There is no firm evidence that the species exists in the state but it may be rare in hilly parts of northern Connecticut. A state DEEP official documented a live cougar in Durham in October 2011. A cougar was killed on the Wilbur Cross Parkway in Milford in June 2011.

  Hoofed mammals

White-tailed deer

• Motor vehicle accidents: State Farm insurance estimates that more than 10,000 deer in Connecticut are hit by cars each year. But the state Department of Environmental Protection estimates only 3,000 deer-motor vehicle accidents occur annually. State policy is to bury deer carcases by the side of the road where they were hit.
• Lyme disease: Culling the deer population in Groton, Connecticut, by about 90 percent reduced the incidence of new Lyme disease cases in town from about twenty a year to two or three a year.
• Habitat damage: In Greenwich, Connecticut, the Greenwich Audubon Society's of land have seen deer push out ground birds such as the ovenbird and black and white warbler. The deer have devastated species of plants once abundant on the Audubon group's land and ravaged low-lying vegetation, including hickory and hemlock saplings. Some once-abundant species in the area were completely absent as of late 2007, according to an Audubon official.

  Moose

Elk

Mammals in Long Island Sound

• Long-finned pilot whale — occasionally enters Long Island Sound; it rarely washes up on the shore in Connecticut.

• Harbor porpoise — rare, but sometimes found off the coast

• Harbor seal — This is the only marine mammal regularly living in Connecticut; found mostly in the eastern part of the coast, but also in the west; not uncommon around Hammonasset Beach State Park, around Sheffield Island and Smith's Reef in the Norwalk Islands, and they have been spotted off Stamford and Greenwich; found from late fall through mid spring, usually on isolated ledges and rocks; in the past, they may have been permanent residents, but sealers and fishermen who killed the seals to prevent competition probably stopped that; for the warmer months of the year, they migrate to the Maine coast.
• Gray seal — occasionally seen in Long Island Sound but usually lives farther north