BioKIDS home

Kids' Inquiry of Diverse Species

eastern grey squirrel

Sciurus carolinensis

What do they look like?

Eastern grey squirrels are medium sized tree squirrels. Males and females are similar in size and color. The fur on their back ranges from grizzled dark grey to pale grey and may have red tones. Their ears are pale grey to white. Their tail is white to pale grey. The underparts are grey to white.

'Melanism' means dark pigmentation. Melanism is common in northern populations of this species. Some populations of eastern grey squirrels are entirely melanistic, so that all squirrels in that area are black over their whole body. If you see a black squirrel, it is most likely an eastern grey squirrel that is melanistic. Some populations of eastern grey squirrels have higher rates of albinism, which results in white fur, but this is very rare.

The total length of the squirrel ranges from 380 to 525 millimeters (mm). The tail length ranges from 150-250 mm.

You can tell eastern grey squirrels apart from fox squirrels by their white tipped fur and white or grayish belly. Eastern grey squirrels often have a lot of red in their fur. Fox squirrels have red-tipped fur and red bellies. Eastern grey squirrels are usually smaller than fox squirrels. In most areas of North America, entirely black eastern grey squirrels are fairly common. These black squirrels will not have white-tipped fur or white bellies. Black fox squirrels are found in some parts of the southeastern United States.

Eastern grey squirrels are larger than red squirrels and do not have the white eye ring around their eyes.

  • Sexual Dimorphism
  • sexes alike
  • Range mass
    338 to 750 g
    11.91 to 26.43 oz
  • Average mass
    540.33 g
    19.04 oz
  • Range length
    380.0 to 525.0 mm
    14.96 to 20.67 in
  • Average basal metabolic rate
    2.062 W
    AnAge

Where do they live?

Eastern grey squirrels are found throughout the eastern United States to just west of the Mississippi River and north into Canada. They have been introduced into some part of the western United states and some areas of Canada where they were not previously found. They have also been introduced into Italy, Scotland, England, and Ireland. In these places eastern grey squirrels are considered a pest species. They compete with native European red squirrels. In some areas, the native squirrels are becoming threatened and endangered as a result of this competition.

What kind of habitat do they need?

Eastern grey squirrels prefer expanses of mature, mixed forest. These squirrels prefer having a continuous forest canopy (upper layer of leaves and branches) so that they can forage and travel mainly in the trees, rather than travelling on the ground. By staying in the trees they are better protected from predators.

Populations of eastern grey squirrels are highest in forests with trees that produce foods that last through winter storage. Oaks, walnuts, and pines are some of the trees produce foods that last through winter storage.

Eastern grey squirrels also use trees for nests. They build leaf nests (collections of leaves) in the higher branches of large trees. Sometimes they use tree cavities and holes as nests for raising their young. These holes are also useful as shelter from extreme weather in winter (hibernation).

  • These animals are found in the following types of habitat
  • temperate

How do they reproduce?

Males compete among themselves for the ability to mate with female eastern grey squirrels. Females may mate with more than one male as well.

Pregnancy lasts 44 days. Most females begin their reproductive life at 1.25 years old but can bear young as early as 5.5 months. Females may bear young twice a year for more than 8 years. Males usually are sexually mature by 11 months but maturity can be delayed by as much as two years if the young males are housed with a dominant adult male. Two litters are born each year in late winter and midsummer with generally 2-4 young per litter(up to 8 young are possible).

  • How often does reproduction occur?
    Eastern grey squirrels breed twice in a year, typically.
  • Breeding season
    Breeding occurs in December-February and May-June and is slightly delayed in more northern latitudes.
  • Range number of offspring
    2.0 to 8.0
  • Average number of offspring
    3.0
  • Average number of offspring
    4
    AnAge
  • Average gestation period
    44.0 days
  • Average gestation period
    44 days
    AnAge
  • Average weaning age
    3.0 weeks
  • Range age at sexual or reproductive maturity (female)
    5.5 (low) months
  • Average age at sexual or reproductive maturity (female)
    15 months
  • Range age at sexual or reproductive maturity (male)
    5.5 (low) months
  • Average age at sexual or reproductive maturity (male)
    15 months

Newborns are naked with the exception of their vibrissae. Vibrissae are small hairs around the nose and mouth that are used for touch, much like the whiskers of a cat. The newborns weigh from 13g to 18g. Young are altricial. They are cared for in the nest by their mother until they reach independence. Weaning begins in the seventh week and is completed by the tenth. At this point, the juvenile hair is lost. Adult size and mass are reached at 9 months old.

  • Parental Investment
  • no parental involvement
  • altricial
  • pre-fertilization
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female
  • pre-independence
    • provisioning
      • female
    • protecting
      • female

How long do they live?

The maximum longevity is 12.5 years in the wild but a captive female lived to be more than 20 years of age.

How do they behave?

During spring, summer, and autumn eastern grey squirrels have their peak activity times about 2 hours after sunrise and 2 to 5 hours before sunset. This allows them to avoid the heat of the day. During the winter, they are diurnal with an activity peak just 2-4 hours before sunset. Generally, females are more active in the summer months and males are more active in the winter months.

Related individuals may defend a territory. Home ranges are generally larger in the summer. The larger the home range territory, the fewer eastern grey squirrels that live there. Squirrels occupy two types of homes. One is a permanent tree den. The other is a nest of leaves and twigs on a tree branch 30 to 45 feet above the ground. Females nest alone when pregnant and lactating. During these times females are especially aggressive and are avoided by others.

Home Range

How do they communicate with each other?

Eastern grey squirrels communicate among themselves with a variety of vocalizations and postures, such as tail flicking. They also have a keen sense of smell. They use their sense of smell to determine many things about their neighbors. Some of the things they can determine are levels of stress and reproductive condition.

What do they eat?

Eastern gray squirrels feed mostly on nuts, seeds, flowers and buds of various trees. These trees include maple, mulberry, hackberry, elm, and dogwood. The seeds they eat usually come from cedar, hemlock, pine, and spruce. They also eat a variety of herbaceous plants and fungi. Crops, such as corn and wheat, are also eaten, especially in the winter. Insects are eaten in the summer and are especially important for young squirrels. Cannibalism has been reported, and squirrels may also eat bones, bird eggs and nestlings, and frogs. They bury food in winter caches using a method called scatter hoarding. They later locate these caches using both memory and smell.

Female eastern grey squirrels need extra protein and minerals from their foods when they are pregnant and nursing young. They may get these from insects, meat, and bones. They also need extra water during nursing. Squirrels can get some moisture from the foods they eat but generally need to drink standing water, which they can get from streams, ponds, puddles, or from small pools of water that collect in tree holes during rains.

  • Animal Foods
  • birds
  • mammals
  • amphibians
  • eggs
  • carrion
  • insects
  • Plant Foods
  • leaves
  • seeds, grains, and nuts
  • fruit
  • Other Foods
  • fungus

What eats them and how do they avoid being eaten?

Eastern grey squirrels are preyed on by many predators, including American mink, other weasels, red foxes, bobcats, grey wolves, coyotes, lynx, and birds of prey, such as red-tailed hawks. They emit warning calls to warn neighboring squirrels of the presence of predators. Their extreme agility in the trees makes them difficult to capture. (Ruff and Wilson, 1999)

What roles do they have in the ecosystem?

Eastern grey squirrels are important members of the forest ecosystems in which they live. They eat a lot of seeds. Their seed-caching activities may help disperse tree seeds. They may help to distribute truffle fungal spores when they eat truffles. They also prey on other animals in the ecosystem where they live. And of course eastern grey squirrels are also prey animals themselves! They are hosts for parasites such as ticks, fleas, lice, and roundworms.

Do they cause problems?

In Great Britain, eastern grey squirrels are considered very destructive to property and are ranked second in negative impact only to the Norway rat. In their native range they are also sometimes considered a household pest. They may build nests in buildings, destroying electrical wiring and woodwork.

  • Ways that these animals might be a problem for humans
  • crop pest
  • household pest

How do they interact with us?

Eastern grey squirrels once provided food for Native Americans and colonists and are still eaten by some people today. They have economic importance in some states, such as Mississippi where 2.5 million are harvested each year with an economic impact of 12.5 million dollars. Squirrels are ranked second to birds in value to nature watchers.

Are they endangered?

Eastern Grey Squirrels are not threatened or in danger.

Some more information...

Some interesting clines, or geographic changes, occur in both skull size and coat color. Going from north to south, skull sizes decrease, even though toothrows and mandible sizes remain the same. Also, more black-coated squirrels occur in the north. It may be that being black gives these squirrels some advantages over grey colored squirrels in colder northern climates.

Contributors

Mara Katharine Lawniczak (author), University of Michigan-Ann Arbor.

References

Banfield, A.W.F. 1981. The Mammals of Canada. University of Toronto Press, Toronto. pp. 132-134.

Jones, Jr., J.K. and E. C. Birney. 1988. Handbook of Mammals of the North-Central States. Univeristy of Minnesota Press, Minneapolis. p.166.

Koprowski, J.L. 2 Dec 94. Mammalian Species No. 480 Sciurus carolinensis. pp.1-9.

"Animal Life History Database" (On-line).

Ruff, S., D. Wilson. 1999. The Smithsonian Book of North American Mammals. Washington [D.C.]: Smithsonian Institution Press in association with the American Society of Mammalogists.

 
University of Michigan Museum of ZoologyNational Science Foundation

BioKIDS home  |  Questions?  |  Animal Diversity Web  |  Cybertracker Tools

Lawniczak, M. 2002. "Sciurus carolinensis" (On-line), Animal Diversity Web. Accessed July 29, 2014 at http://www.biokids.umich.edu/accounts/Sciurus_carolinensis/

BioKIDS is sponsored in part by the Interagency Education Research Initiative. It is a partnership of the University of Michigan School of Education, University of Michigan Museum of Zoology, and the Detroit Public Schools. This material is based upon work supported by the National Science Foundation under Grant DRL-0628151.
Copyright © 2002-2014, The Regents of the University of Michigan. All rights reserved.

University of Michigan