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Eastern Gray Squirrel

Sciurus carolinensis

Summary 4

The eastern gray squirrel or grey squirrel (depending on region), Sciurus carolinensis, is a tree squirrel in the genus Sciurus.

Habitat and ecology 5

Habitat and Ecology

It is found in large blocks of hardwood or mixed forests, as well as in urban and suburban areas. Prefers mature deciduous and mixed forests with abundant supplies of mast (e.g., acorns, hickory nuts). A diversity of nut trees is needed to support high densities. Also uses city parks and floodplains. Seldom far from permanent open water. In southern Alabama, narrow bands of hardwoods along ephemeral streams were an important component of the habitat in even-aged pine and mixed pine-hardwood stands. Rests in tree cavity or leaf nest; leaf nests apparently are made primarily by dispersing juveniles 18-19 weeks old. Nests in tree cavities or in leaf nests, usually 25 feet or more above the ground. Most winter-spring litters are born in tree cavities, most spring-summer litters in leaf nests (Teaford 1986). Cavities suitable for nesting are dry, 15-25 cm in diametre, 40-50 cm deep, with an entrance hole about eight cm in diameter (Teaford 1986). Females may move young from tree cavity nest to leaf nest, possibly to escape fleas.

In Illinois, most breeding occurs in December-February and May-June; slightly later in more northern latitudes (see Koprowski 1994). One or two litters per year. First litter is produced mostly in February-March, sometimes as early as January in some areas; second litter, July or August. Gestation lasts 44 days. Litter size most often is 2-3. Young are tended by female. Weaning is completed at about 10-12 weeks (in spring and/or late summer-early fall). Most breed as yearlings, sometimes sooner (as early as five months) or later. Reproductive output, including the percentage of adults that produce young and the number of litters per year, is positively correlated with mast abundance. Maximum reproductive longevity is about a decade.

Home range averages 0.5-10 ha, with older males tending to have the largest ranges (Teaford 1986); usually home range is less than five hectares (see Koprowski 1994). Not territorial, home range overlap is extensive; social system is characterized by a linear dominance hierarchy. Disperses up to a few kilometres from natal area upon approaching sexual maturity. Large-scale one-way emigrations have been observed, generally coinciding with high population density and mast crop failure.

Taken by many predators, but predation does not appear to limit populations (Teaford 1986). Mean annual mortality reported for adults is 42-57% (Koprowski 1994). Diet consists of seeds, fruits, nuts, fungi, occasional insects and small vertebrates (e.g., bird eggs). Scatterhoarder; buries nuts and acorn in fall for later consumption (winter-spring). Active during the day, particularly in the morning and late afternoon, though unimodal activity may occur in winter. May be inactive for a day or two during extremely cold, snowy weather.

Systems
  • Terrestrial

Associations 6

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

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.

Ecology 7

Fall density generally ranges from 0.5 to 14/ha, but 3.2/ha generally is considered high for extensive forested tracts; densities of 21/ha or more may occur in city parks; populations tend to increase after bumper mast crops, decrease if mast crop fails (Teaford 1986). May aggregate at abundant food sources.

Home range averages 0.5-10 ha, with older males tending to have the largest ranges (Teaford 1986); usually home range is less than 5 ha (see Koprowski 1994). Not territorial, home range overlap is extensive; social system is characterized by a linear dominance hierarchy.

Disperses up to a few kilometers from natal area upon approaching sexual maturity. Large-scale one-way emigrations have been observed, generally coinciding with high population density and mast crop failure.

Taken by many predators, but predation does not appear to limit populations (Teaford 1986). Mean annual mortality reported for adults is 42-57% (Koprowski 1994).

Behaviour 8

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 and can determine much about their neighbors in this way, including levels of stress and reproductive condition.

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.

Communication Channels: visual ; tactile ; acoustic ; chemical

Perception Channels: visual ; tactile ; acoustic ; chemical

Threats 9

Major Threats

There are no major threats to this species.

Sources and Credits

  1. (c) David Friel, some rights reserved (CC BY), http://www.flickr.com/photos/92163630@N00/1916162087
  2. (c) Jim Ferguson, some rights reserved (CC BY), https://upload.wikimedia.org/wikipedia/commons/thumb/2/23/Sciurus_carolinensis-gotigersjf.jpg/460px-Sciurus_carolinensis-gotigersjf.jpg
  3. Ken Thomas, no known copyright restrictions (public domain), https://upload.wikimedia.org/wikipedia/commons/thumb/9/9d/Sciurus_carolinensis2.jpg/460px-Sciurus_carolinensis2.jpg
  4. (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Sciurus_carolinensis
  5. (c) International Union for Conservation of Nature and Natural Resources, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/34717219
  6. (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/31421885
  7. (c) NatureServe, some rights reserved (CC BY-NC), http://eol.org/data_objects/28915980
  8. (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/31421882
  9. (c) International Union for Conservation of Nature and Natural Resources, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/34717220

More Info

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(c) Discover Life and original sources, some rights reserved (CC-BY-NC-SA)

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