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Mammals of Connecticut

The mammals most often spotted in Connecticut, ranked by recent research-grade observations.

26,531
recent observations
50
species listed
50
mammals

Naturalists have logged 26,531 research-grade observations across the 50 most-recorded species in Connecticut. The most frequently seen is the White-tailed Deer, with 4,436 recorded sightings.

Rarer finds confirmed in Connecticut include Bobcat and Fisher - uncommon enough that a sighting is worth logging.

BobcatFisher

Most-observed mammals in Connecticut

White-tailed Deer
Odocoileus virginianus
4,436 observations
Eastern Gray Squirrel
Sciurus carolinensis
4,148 observations
Eastern Cottontail
Sylvilagus floridanus
2,585 observations
Bobcat
Lynx rufus
1,811 observations
Eastern Chipmunk
Tamias striatus
1,794 observations
Red Fox
Vulpes vulpes
1,498 observations
Common Raccoon
Procyon lotor
1,339 observations
Coyote
Canis latrans
1,242 observations
American Black Bear
Ursus americanus
1,122 observations
Groundhog
Marmota monax
1,062 observations
Virginia Opossum
Didelphis virginiana
953 observations
American Beaver
Castor canadensis
754 observations
American Red Squirrel
Tamiasciurus hudsonicus
591 observations
Striped Skunk
Mephitis mephitis
436 observations
Northern Short-tailed Shrew
Blarina brevicauda
294 observations
Muskrat
Ondatra zibethicus
250 observations
White-footed Mouse
Peromyscus leucopus
192 observations
Domestic Cat
Felis catus
190 observations
North American Porcupine
Erethizon dorsatum
180 observations
American Mink
Neogale vison
167 observations
Harbor Seal
Phoca vitulina
150 observations
Gray Fox
Urocyon cinereoargenteus
149 observations
Grey Seal
Halichoerus grypus
138 observations
North American River Otter
Lontra canadensis
113 observations
Big Brown Bat
Eptesicus fuscus
112 observations
Eastern Meadow Vole
Microtus pennsylvanicus
109 observations
Brown Rat
Rattus norvegicus
102 observations
Southern Flying Squirrel
Glaucomys volans
100 observations
Eastern Mole
Scalopus aquaticus
64 observations
Moose
Alces alces
55 observations
Eastern Red Bat
Lasiurus borealis
48 observations
Long-tailed Weasel
Neogale frenata
46 observations · iNaturalist
Fisher
Pekania pennanti
43 observations
Masked Shrew
Sorex cinereus
33 observations
American Ermine
Mustela richardsonii
27 observations
Humpback Whale
Megaptera novaeangliae
23 observations
Star-nosed Mole
Condylura cristata
23 observations
House Mouse
Mus musculus
20 observations
Tamanend's Bottlenose Dolphin
Tursiops erebennus
20 observations
Woodland Vole
Microtus pinetorum
15 observations
Harp Seal
Pagophilus groenlandicus
14 observations
Northern Meadow Jumping Mouse
Zapus hudsonius
13 observations
Hairy-tailed Mole
Parascalops breweri
13 observations
Silver-haired Bat
Lasionycteris noctivagans
12 observations
Fin Whale
Balaenoptera physalus
12 observations
Common Dolphin
Delphinus delphis
9 observations
Domestic Dog
Canis familiaris
8 observations · iNaturalist
Eastern Deer Mouse
Peromyscus maniculatus
6 observations
Eastern Woodland Jumping Mouse
Napaeozapus insignis
5 observations
Smoky Shrew
Sorex fumeus
5 observations

Built from recent research-grade iNaturalist observations. Identifications are community-sourced and may occasionally be wrong, and the ranking reflects where people record and photograph wildlife, so a species seen often here is not necessarily rare elsewhere. Some plants and animals are only out in certain seasons. Treat this as a lively snapshot of what people are finding, not a formal checklist.

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