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Eastern gray squirrel field guide

Field Guide

Common name	Eastern gray squirrel
Scientific name	Sciurus carolinensis
Family	Sciuridae (squirrels)
Size	Total length 380 to 525 mm, tail 150 to 250 mm; Missouri: 14 to 21 inches totalAnimal Diversity Web, University of Michigan Museum of Zoology · Missouri Department of Conservation
Weight	338 to 750 g, average 540.33 g; Missouri: 3/4 to 1 1/2 poundsAnimal Diversity Web, University of Michigan Museum of Zoology · Missouri Department of Conservation
Lifespan	Up to 12.5 years in the wild; a captive female lived more than 20 yearsAnimal Diversity Web, University of Michigan Museum of Zoology
Diet	Omnivore: mostly nuts (acorns, hickory, walnut, beech), seeds, buds, flowers, fruit and fungi; also corn, insects, bird eggs, nestlings and frogsAnimal Diversity Web, University of Michigan Museum of Zoology · Mass Audubon
Active when	Daytime, year-round; spring to fall peaks about 2 hours after sunrise and 2-5 hours before sunset; winter single peak 2-4 hours before sunsetAnimal Diversity Web, University of Michigan Museum of Zoology · Mass Audubon
Range	Eastern United States to just west of the Mississippi River and north to Canada; introduced in western states and parts of CanadaAnimal Diversity Web, University of Michigan Museum of Zoology
Conservation status	IUCN Red List: Least Concern; NatureServe global rank G5 (Secure)NatureServe Explorer · Animal Diversity Web, University of Michigan Museum of Zoology

Field Marks

Grizzled dark to pale gray back, sometimes with cinnamon tones; underparts gray to buff; ears pale gray to whiteAnimal Diversity Web, University of Michigan Museum of Zoology
Tail fringe and belly white, separating it from the larger eastern fox squirrel, whose tail fringe and belly are reddish yellowMissouri Department of Conservation
Many have white trim on the back of the ears and a straw-colored ring around the eyesOhio Department of Natural Resources
Large fluffy tail almost half its body lengthMass Audubon
Black (melanistic) and white individuals are gray squirrels with more or less pigment, not separate species; true albinos have pink eyesMass Audubon

Habitat

Prefers mature continuous woodland larger than 40 hectares with diverse understory; densities are highest where oaks and walnuts supply storable winter foodAnimal Diversity Web, University of Michigan Museum of Zoology
Comfortable in suburbs and cities; in Massachusetts look for it wherever nut-bearing trees such as oak, hickory or beech growMass Audubon
In Missouri more common in bottomlands and along rivers with a bushy understory; also lives in urban areas, especially where large oak and hickory trees are commonMissouri Department of Conservation
Uses two kinds of home: a permanent tree den and a nest of leaves and twigs (drey) on a tree crotch 30-45 feet above the groundAnimal Diversity Web, University of Michigan Museum of Zoology
Dreys can be a foot or two wide, usually 20 feet or higher, built near the trunk or in a strong fork of a food tree such as an oakMass Audubon
Each squirrel uses a home range of no more than 5 acres in the Chesapeake Bay watershedChesapeake Bay Program

Behavior

Scatter-hoards: buries food in many separate caches across the landscape rather than one storeAnimal Diversity Web, University of Michigan Museum of Zoology · Scientific American
Finds caches by both memory and smellAnimal Diversity Web, University of Michigan Museum of Zoology
In a 1991 enclosure study of eight hand-raised gray squirrels given 10 nuts each, they retrieved twice as many of their own nuts as another squirrel's and planned routes through their cachesScientific American
In a 1997 experiment, gray squirrels could remember up to 24 cache locations for up to two monthsScientific American
Many unrecovered buried nuts eventually germinate, so squirrels essentially plant nut trees; ADW says seed caching may help disperse tree seedsMissouri Department of Conservation · Animal Diversity Web, University of Michigan Museum of Zoology
Bird feeders provide a bonanza of food; squirrels can jump six feet straight up and launch 10 feet or more from a tree, building or railing to reach oneMass Audubon
Takes birds' eggs and nestlings from open nests and gnaws into birdhouses in summerMass Audubon
Communicates with vocalizations and postures such as tail flicking, and reads stress and breeding condition of neighbors by smellAnimal Diversity Web, University of Michigan Museum of Zoology
Becomes noisy when alarmed or angry, chattering, rasping and barking; gives warning calls when predators are nearChesapeake Bay Program
Breeds twice a year, December-February and May-June, slightly later farther north; courtship features noisy chases through the treetopsAnimal Diversity Web, University of Michigan Museum of Zoology · Mass Audubon
Gestation is 44 days; litters, born in late winter and midsummer, are generally 2-4 young (up to 8)Animal Diversity Web, University of Michigan Museum of Zoology
Young are born without teeth or fur, eyes and ears shut; eyes open at about 36 days and they venture out of the nest onto the ground at about 10 weeksOhio Department of Natural Resources
More social than fox and red squirrels; several gray squirrels may share a shelter nestOhio Department of Natural Resources
Gnaws constantly on bark, wood, plastic or metal because its incisors grow throughout lifeMass Audubon
Often eats sitting on rocks or logs, leaving piles of walnut, hickory and acorn shellsMissouri Department of Conservation

Winter

Stays active year-round and can feed in rain or snowstorms, keeping dry and warm under its broad tail arched and spread over its backMass Audubon
Mass Audubon: in winter gray squirrels only come out at midday. ADW: winter activity has a single peak 2-4 hours before sunsetMass Audubon · Animal Diversity Web, University of Michigan Museum of Zoology
Tree cavities are preferred homes, especially in winter; large cavities are commonly filled with leaves in fall and spring for insulation. Winter-built leaf nests use bare twigs with interlaced leaves and are usually very substantialMissouri Department of Conservation
Studies cited by ADW found black-morph squirrels have 18% lower heat loss below -10 degrees Celsius, a 20% lower basal metabolic rate and 11% higher nonshivering thermogenesis capacity than gray morphsAnimal Diversity Web, University of Michigan Museum of Zoology
In Ohio, gray squirrel winter survival and spring reproduction are closely tied to the previous fall's mast crop; in Missouri, squirrel numbers fluctuate after good or bad mast yearsOhio Department of Natural Resources · Missouri Department of Conservation

Questions

How big is an eastern gray squirrel?

Total length is 380 to 525 mm (about 15 to 21 inches), with a tail of 150 to 250 mm. Adults weigh 338 to 750 g, about 3/4 to 1 1/2 pounds.Animal Diversity Web, University of Michigan Museum of Zoology · Missouri Department of Conservation

Why do squirrels bury acorns?

Gray squirrels scatter-hoard, burying nuts in many separate caches to eat in winter. They find them again using memory and smell.Animal Diversity Web, University of Michigan Museum of Zoology · Scientific American

Do squirrels remember where they buried their nuts?

Yes, in experiments. In a 1991 enclosure study eight hand-raised gray squirrels retrieved twice as many of their own nuts as another squirrel's, and in a 1997 experiment they remembered up to 24 caches for up to two months.Scientific American

Is a black squirrel a different species?

No. Black squirrels are melanistic gray squirrels with more pigment than normal; Mass Audubon says their incidence seems to be greater in the North, and ADW also reports more black-coated squirrels in the north.Mass Audubon · Animal Diversity Web, University of Michigan Museum of Zoology

Where do squirrels sleep in winter?

In tree cavities lined with leaves, or in leaf-and-twig nests called dreys. Winter dreys are built of bare twigs with interlaced leaves and are sturdier than summer nests.Missouri Department of Conservation · Mass Audubon

Do gray squirrels hibernate?

No. Mass Audubon says squirrels remain active year-round and can feed during rain or snowstorms, keeping dry and warm under their tail.Mass Audubon

Why is a squirrel always at my bird feeder?

Squirrels love seeds, and bird feeders provide a bonanza of nourishment. They can jump six feet straight up and launch 10 feet or more from a tree, building or railing to reach a feeder.Mass Audubon

What eats squirrels?

Predators include mink, weasels, red foxes, bobcats, coyotes, owls, hawks, domestic cats and dogs. Squirrels give warning calls when a predator is near.Animal Diversity Web, University of Michigan Museum of Zoology · Missouri Department of Conservation · Chesapeake Bay Program

Why does a squirrel flick its tail?

Tail flicking is one of the postures gray squirrels use to communicate. The tail is also used for balance and warmth.Animal Diversity Web, University of Michigan Museum of Zoology · Chesapeake Bay Program

Clips

A gray squirrel clings head-down at the top of a wooden nest box caked with snow, with snowy bare branches, a white-sided house and a fence behind it.

Gray squirrel clings to a snow-caked nest box

A gray squirrel seen from behind sits on a wooden rail with its head at the rim of a white cup, bushy gray tail hanging down, a black wire fence and green leaves beyond.

Trash can milkshake for a New York gray squirrel

Seen from behind, a gray squirrel stands on its hind legs on a white deck rail with its forepaws on a white PVC pipe, facing a large red disc under the corner of a white roof, its bushy tail hanging over the rail and leafy trees behind.

Pizza plate feeder stumps a gray squirrel

A black squirrel stands on its hind legs in snow beside a tree trunk, its front paws resting on an outstretched hand holding dark seeds, with more seeds scattered on the snow.

Black squirrel takes seeds from a hand in snow

An eastern gray squirrel with a white chest sits on a frost-dusted ledge facing the camera, one front paw raised, its bushy tail arched up over its back, snow-covered shrubs to the left and a corner of brick wall at top right.

Gray squirrel tail-up on a snowy window ledge

An eastern gray squirrel stands upright on a sunlit snowbank looking up at the camera, snow flecks on its face, forepaws at its pale chest, a dark hole in the snow at lower left.

Gray squirrel stands tall in a tunneled snowbank

An eastern gray squirrel crouches on brown fallen leaves facing left, one front paw raised, a pale ring around its dark eye, the woodland floor blurred behind.

Gray squirrel fakes a burial to fool a thief

Two eastern gray squirrels share one snow-caked nest box through a severe Midwest storm, curling up and tussling until one is ready to head out.

An eastern gray squirrel in a New York trash can pulls the straw from a Shake Shack cup and drinks the chocolate shake while the people filming cheer from above.

A gray squirrel on a deck rail weighs a jump to a chickadee feeder guarded by a red pizza plate and spinning PVC joints, while others land on it and slide off.

Little Bean, a black squirrel who lost fur to a skin condition one winter, stands in the snow with her paws on a hand of seeds, her coat grown back.

A gray squirrel sits tail-up on a frosted ledge outside a window in deep snow, and another squirrel at the same window tries to make off with the whole nut bowl.

Squirrels dig tunnels through a deep backyard snowbank to reach a feeding window, and one stands up in the sun with snow on its nose.

A gray squirrel that lost one buried acorn to a thief stages a fake burial for her and keeps the real nut in his mouth.

Sources

Sciurus carolinensis (eastern gray squirrel), Animal Diversity Web, University of Michigan Museum of Zoology
Squirrels (Eastern gray squirrel), Mass Audubon
Eastern Gray Squirrel and Eastern Fox Squirrel, Missouri Department of Conservation
Eastern Gray Squirrel, Ohio Department of Natural Resources
Eastern gray squirrel (Field Guide), Chesapeake Bay Program
Sciurus carolinensis, NatureServe Explorer
Do Squirrels Remember Where They Buried Their Nuts? (Emma Bryce, 2023-11-20; reports Jacobs & Liman 1991, Animal Behaviour 41:103-110), Scientific American