Eastern Gray Squirrel: Facts, Diet, Habitat and Behavior

What does an eastern gray squirrel look like?

As its name suggests, the gray squirrel is mostly gray, often with a brownish or reddish wash along the back, flanks and feet. The belly is white or pale gray, and the long, bushy tail is gray with a silvery white fringe. The ears are rounded and lack the long tufts of the Eurasian red squirrel, although they can look slightly fuzzy in winter.

Not every gray squirrel is gray. A black (melanistic) form is common in parts of its range, especially around the Great Lakes, and in some places in Ontario and Michigan black animals outnumber gray ones. There are also brownish-black squirrels, rare white (leucistic) squirrels and very rare true albinos. All are the same species, and the reasons are explained in why some squirrels are black.

Males and females look the same and are about the same size. Like all squirrels, gray squirrels have four toes on the front feet and five on the hind feet, and their front teeth, the incisors, keep growing throughout life, as in all rodents.

How big is a gray squirrel?

Gray squirrels are larger and heavier than red squirrels but smaller than the North American fox squirrel, with which they share much of their range.

Weight changes with the seasons. Squirrels put on fat in autumn, when acorns and other nuts are plentiful, and lose some of it during late winter, when food is hardest to find. The tail serves as a balancing aid when running along branches, a parasol in sun, a blanket in cold weather and a signal flag to other squirrels.

Habitat and range

The eastern gray squirrel is native to the eastern and midwestern United States and to southern Canada, from New Brunswick, southern Quebec and southern Ontario west to southern Manitoba, and south to Florida and eastern Texas. It is a forest animal at heart, preferring large areas of mature broadleaf woodland with nut-producing trees such as oaks, hickories, walnuts and beeches. It is scarce in dense conifer forest and absent from the boreal forest of the north.

The species has adapted superbly to people. City parks, cemeteries, college campuses and leafy suburbs, with their big old trees and bird feeders, often hold more squirrels than natural woodland.

People have spread gray squirrels far beyond their native range. They were introduced to several places in western North America, including Seattle, San Francisco, Vancouver Island and Calgary. Overseas, they were released in Britain from 1876, in Ireland in 1911, in Italy from 1948 and in the Western Cape of South Africa around 1900. An Australian population died out by the 1970s.

What do gray squirrels eat?

Gray squirrels are mainly seed and nut eaters, but technically they are omnivores. Their staple foods are acorns, hickory nuts, walnuts, beechnuts and hazelnuts, plus tree seeds such as maple keys and pine seeds. In spring, before the new crop of nuts, they eat tree buds, flowers and shoots. Summer brings berries, fruit and fungi, including truffles that they dig up by smell.

They also take animal food when they find it: insects, bird eggs and nestlings, and occasionally frogs. Squirrels gnaw shed antlers and bones, probably for minerals. In towns they raid bird feeders for sunflower seeds and corn. The full menu is covered in what squirrels eat.

The gray squirrel’s real specialty is acorns. It digests them better than the red squirrel does, which is one reason it does so well in oak woods in Britain.

Burying nuts: the scatter-hoarder

In autumn a gray squirrel buries nuts one at a time in shallow holes scattered across its home range, a habit called scatter-hoarding. A single squirrel may make several thousand of these caches in one season. It finds most of them again months later using spatial memory and landmarks, helped by its sense of smell at close range.

Gray squirrels are surprisingly sophisticated about it. They tend to eat acorns of white oaks, which sprout quickly in autumn, right away, and bury the longer-lasting red oak acorns. They sometimes bite out the embryo of an acorn so it cannot germinate, and they may perform fake burials when another squirrel or a jay is watching. Read more in do squirrels remember where they bury nuts?

Nuts that are never dug up can grow into new trees, so gray squirrels play an important role in spreading oaks, hickories and walnuts through the forest.

Behavior and nests

Gray squirrels are active by day, most of all in the first hours after sunrise and in the late afternoon. They are agile climbers and one of the few mammals that can run down a tree trunk head-first, which they do by rotating their hind feet backward so the claws grip the bark.

They do not hibernate. Instead they rest in two kinds of home: a hole in a tree, called a den, or a drey, a ball of twigs and leaves about 30–60 cm (1–2 ft) across, built in a fork of branches and lined with moss, grass and shredded bark. Tree dens are warmer and safer, and squirrels often claim two or three nests at once. In cold weather several squirrels may share a nest to keep warm, as explained in do squirrels hibernate?

Gray squirrels are not territorial in the strict sense. Home ranges overlap widely, and squirrels sort out access to food through a dominance hierarchy in which older, heavier animals usually win. They communicate with chattering calls, a “kuk” alarm call, a mewing “quaa”, soft contact sounds between mothers and young, and a great deal of tail flicking. A rapidly flicked tail is a common sign of alarm or irritation.

Reproduction and life cycle

Gray squirrels have two breeding seasons each year, from about December to February and again from May to June, slightly later in the north. A female in season attracts a crowd of males, which follow her through the trees in a noisy mating chase; she usually mates with more than one.

After a pregnancy of about 44 days, the female gives birth in a den or drey to a litter of usually 1–4 young, occasionally more. The kits are born naked, blind and pink. Their eyes open at about three to six weeks, they start to leave the nest at around 10–12 weeks and are fully weaned by about that age. Young females can breed in their first year, but most first breed at about 1–2 years old. Experienced females may raise two litters in a year when food is plentiful, and none in a year when the acorn crop fails.

How long do gray squirrels live?

Most gray squirrels die young. Only about one in four survives its first year, and life expectancy at birth is just one to two years. An adult that makes it through that dangerous period may live to around six, and wild females have been recorded breeding at more than 12 years old. In captivity, gray squirrels can live for about 20 years. The full picture is in how long squirrels live.

Predators and threats

In North America gray squirrels are hunted by hawks such as the red-tailed hawk, owls, snakes, foxes, bobcats, weasels, raccoons and domestic cats. Cars kill large numbers in towns. Squirrels rely on alarm calls, sharp eyesight and a quick dash to the far side of a trunk to escape.

In Britain and Ireland the gray squirrel has few natural predators. The main exception is the pine marten, and in areas of Ireland and Scotland where martens have recovered, gray squirrel numbers have fallen and red squirrels have returned.

Conservation status

The IUCN Red List classifies the eastern gray squirrel as Least Concern. It is abundant over a huge range, thrives alongside people and has expanded into new areas with human help.

Outside its native range the picture is reversed. Britain’s gray squirrel population is commonly estimated at around 2.7 million, and the species has replaced the red squirrel across most of England and Wales. The European Union lists it as an invasive alien species of Union concern, which bans importing, keeping, breeding or releasing it. The background is explained in why gray squirrels are invasive in the UK.

Myths and facts

Myth: Gray squirrels kill red squirrels. There is no evidence that gray squirrels attack red squirrels. They replace them by outcompeting them for food and by spreading squirrelpox, a virus that rarely harms grays but is usually fatal to reds.

Myth: Squirrels forget where they buried their nuts. Experiments show gray squirrels remember their own cache sites well. They do leave some nuts behind, especially in years of plenty, and those forgotten nuts help plant forests.

Myth: Black squirrels are a different species. In eastern North America nearly all black squirrels are simply eastern gray squirrels with a dark coat, caused by a variant of a single pigment gene.

Relationship with people

Gray squirrels are among the most watched wild mammals in North America and Europe, and for many city children they are the first wild mammal they get to know. Their acrobatics at bird feeders are famous. They can also be a nuisance, nesting in attics, chewing wiring and digging up bulbs. In Britain they strip bark from young broadleaf trees such as beech, sycamore and oak, which damages timber and can kill trees.