The number of species of mammals commonly found to live in Connecticut seems to be around 40. Mammals have fur or hair and produce milk to feed their offspring. Most bear live young, although a few egg-laying mammals, such as the bizarre duck-billed platypus of Australia, exist. Humans are mammals, but I didn't create an entry for humans even though yes, humans live in Connecticut!
Bats
Beaver
Black Bear
Bobcat
Chipmunk
Cottontail Rabbit
Coyote
Deer
Fisher
Florida Manatee
Flying Squirrel
Gray Fox
Gray Squirrel
Harbor Seal
Lemming
Mice
Mink
Mole
Moose
Muskrat
Opossum
Porcupine
Raccoon
Rats
Red Fox
Red Squirrel
River Otter
Shrews
Skunk
Snowshoe Hare
Star-nosed Mole
Vole
Weasels
Woodchuck