Articles on this page are available in 1 other language: Spanish (2) (learn more)

Overview

Brief Summary

Description

"The adaptable, omnivorous, diurnal Eastern Gray Squirrel is the native American mammal people most frequently see east of the Mississippi River. It prefers to den inside trees, but will construct large nests of leaves in the canopy if tree cavities are not available. An average of two to three blind, hairless young make up a litter. Litters are produced once or twice a year, in February and March and again in July through September. The young are weaned at eight or nine weeks, when their previously protective mother abandons them. In September, yearlings and some adults strike out to establish their own home ranges in a process called the ""fall reshuffle."" These home ranges are rarely more than one or two hectares in size. Successful as they are, Eastern Gray Squirrels live only 11-12 months on average, but some individuals have survived more than ten years in the wild. Factors affecting survival include the severity of winter, abundance of food, and parasites. One parasite, the mange mite, may cause enough hair loss to threaten survival through winter."

Links:
Mammal Species of the World
Click here for The American Society of Mammalogists species account
  • Original description: Gmelin, J.F., 1788.  Caroli a Linne Systema Naturae, p. 148.  13th edition. George Emanuel Beer, Leipzig, 4120 pp.
Creative Commons Attribution 3.0 (CC BY 3.0)

© Smithsonian Institution

Source: Smithsonian's North American Mammals

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Biology

Grey squirrels are active during the day (6); they feed on seeds, nuts, buds, insects, bird eggs (6) and fungi, depending on the time of year (3), and are well-known for their habit of hoarding food in autumn to see them through the harsh winter months (3). Seeds, cones or nuts are hidden in small scrapes scattered over the ground and buried (3). The general area is remembered, and then the cache is re-found by smell over fairly short distances (3). Breeding takes place in December to February, and again in March to May. During this time, a number of males may follow a female when she is about to come into oestrus; during this 'following phase' the female may occasionally turn on the male and rebuff his advances by lunging at him aggressively. The day the female comes into oestrus, a number of males chase the female, making 'buzzing' noises; this is known as the 'mating chase', and the female can respond aggressively to males. Through much male-male chasing, dominant males are able to get closer to the female; when she is ready she crouches on the ground, and the first male to reach her mates with her (3). Gestation takes up to 44 days, during which time females are solitary, and nest in a 'drey' of twigs and leaves (1). If conditions are good (6), two litters are produced each year, consisting of one to eight young (6). The young are usually weaned by ten weeks (1), and reach sexual maturity at 10 to 12 months of age (6). The average lifespan is eight to nine years (6).
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© Wildscreen

Source: ARKive

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Description

Although a familiar mammal in many parts of Great Britain, the grey squirrel is non-native, having been first introduced from the eastern USA in 1876 (3). It is responsible for the decline in populations of our native red squirrel (Sciurus vulgaris) (3). The introduced species is larger than the red squirrel, has largely grey fur with touches of russet-brown, and white underparts (2). Unlike the red squirrel, this species never has ear tufts (2). The sexes are similar in appearance (1).
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© Wildscreen

Source: ARKive

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Distribution

National Distribution

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© NatureServe

Source: NatureServe

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Global Range: Eastern U.S. and adjacent southern Canada; southern Quebec to Manitoba, south to eastern Texas and Florida. Range has been extended through introductions into Quebec, Ontario, New Brunswick, Manitoba, Saskatchewan, British Columbia, Nova Scotia, California, Oregon, Washington, and Montana (Teaford 1986, Koprowski 1994). Introduced also in the British Isles, Italy, South Africa, and Australia (extirpated by 1973) (see Koprowski 1994).

Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© NatureServe

Source: NatureServe

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Range Description

This species is found in the eastern United States and adjacent southern Canada; southern Quebec to Manitoba, south to eastern Texas and Florida. Its range has been extended through introductions into Quebec, Ontario, New Brunswick, Manitoba, Saskatchewan, British Columbia, Nova Scotia, California, Oregon, Washington, and Montana (Teaford 1986, Koprowski 1994). It is also introduced in the British Isles, Italy, South Africa, and Australia (extirpated by 1973), but these introduced ranges are not included in the map here (see Koprowski 1994).
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© International Union for Conservation of Nature and Natural Resources

Source: IUCN

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Geographic Range

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.

Biogeographic Regions: nearctic (Introduced , Native ); palearctic (Introduced )

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: BioKIDS Critter Catalog

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Geographic Range

Sciurus carolinensis ranges over the eastern United States to just west of the Mississippi River and north to Canada. Introductions have occurred in the western states and some of Canada that was not previously inhabited, as well as in Italy, Scotland, England and Ireland.

Biogeographic Regions: nearctic (Introduced , Native ); palearctic (Introduced )

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: Animal Diversity Web

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Range

Introductions of this species to the UK continued up until 1915. Between 1930 and 1945 it underwent a huge expansion in range; it is now common throughout central and southern England, Wales and the central lowlands of Scotland (3), and is still increasing in terms of range and numbers (6). The grey squirrel has also been introduced to South Africa, Australia (3) and Italy (4). In Italy the species has extended its range into the Alps and Piedmont, and it seems likely that it will now spread throughout much of Europe (4). Its native range extends throughout the eastern USA reaching as far north as Canada, and south to the Mississippi River (1).
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© Wildscreen

Source: ARKive

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Physical Description

Morphology

Physical Description

Eastern grey squirrels are medium sized Sciuridae. 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 Tamiasciurus hudsonicus and do not have the white eye ring around their eyes.

Range mass: 338 to 750 g.

Average mass: 540.33 g.

Range length: 380.0 to 525.0 mm.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: sexes alike

Average basal metabolic rate: 2.062 W.

  • 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.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: BioKIDS Critter Catalog

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Physical Description

Sciurus carolinensis is a medium sized tree squirrel with no sexual dimorphism in size or coloration. The dorsal surface ranges from grizzled dark to pale grey and may have cinnamon tones. The ears are pale grey to white and its tail is white to pale grey. Underparts are grey to buff. Melanism is common in the northern portions of the range and albinism is rare in all areas. There are a total of 22 teeth in the adults with a dental formula of i (1/1), c (0/0), p (2/1/), m (3/3). The total length of these squirrels ranges from 380 to 525 mm, tail length ranges from 150 to 250 mm, ear length ranges from 25 to 33mm, and hind foot length ranges from 54 to 76mm.

Range mass: 338 to 750 g.

Average mass: 540.33 g.

Range length: 380.0 to 525.0 mm.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: sexes alike

Average basal metabolic rate: 2.062 W.

  • 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.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: Animal Diversity Web

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Size

Length: 50 cm

Weight: 710 grams

Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© NatureServe

Source: NatureServe

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Size in North America

Sexual Dimorphism: None

Length:
Average: 473 mm
Range: 383-525 mm

Weight:
Average: 520 g
Range: 338-750 g
Creative Commons Attribution 3.0 (CC BY 3.0)

© Smithsonian Institution

Source: Smithsonian's North American Mammals

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Ecology

Habitat

Comments: 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 (Fischer and Holler 1991). 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 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 diameter, 40-50 cm deep, with an entrance hole about 8 cm in diameter (Teaford 1986). Females may move young from tree cavity nest to leaf nest, possibly to escape fleas.

Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© NatureServe

Source: NatureServe

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Habitat and Ecology

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
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© International Union for Conservation of Nature and Natural Resources

Source: IUCN

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

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).

Habitat Regions: temperate

Terrestrial Biomes: forest

Other Habitat Features: urban ; suburban

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: BioKIDS Critter Catalog

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Sciurus carolinensis prefers habitats of mature continuous woodlands of greater than 40 hectares with diverse understory vegetation. Densities are highest in forests with trees that produce foods that last through winter storage such as oaks (Quercus) and walnuts (Juglans).

Habitat Regions: temperate

Terrestrial Biomes: forest

Other Habitat Features: urban ; suburban

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: Animal Diversity Web

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

A very adaptable species, the grey squirrel prefers mature broadleaved woodlands with a rich understorey layer (1). It also occurs in conifer woodlands, urban areas where there are mature trees, as well as gardens and parks (6).
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© Wildscreen

Source: ARKive

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Migration

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

Massive movements may occur in some years.

Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© NatureServe

Source: NatureServe

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Trophic Strategy

Comments: 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).

Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© NatureServe

Source: NatureServe

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Food Habits

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. Insecta are eaten in the summer and are especially important for young squirrels. Cannibalism has been reported, and squirrels may also eat bones, Aves eggs and nestlings, and Anura. 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

Foraging Behavior: stores or caches food

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: BioKIDS Critter Catalog

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Food Habits

Sciurus carolinensis feeds mostly on nuts, flowers and buds of more than 24 species of oaks, 10 species of hickory, pecan, walnut and beech tree species. Maple, mulberry, hackberry, elm, bucky and horse chestnut fruits, seeds, bulbs or flowers are also eaten along with wild cherry, dogwood, hawthorn, black gum, hazelnut, hop hornbeam and gingko tree fruits, seeds, bulbs and/or flowers. The seeds and catkins of gymnosperms such as cedar, hemlock, pine, and spruce are another food source along with a variety of herbaceous plants and fungi. Crops, such as corn and wheat, are eaten, especially in the winter. Insects are eaten in the summer and are probably especially important for juveniles. 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 and locate these caches using both memory and smell.

Animal Foods: birds; mammals; amphibians; eggs; carrion ; insects

Plant Foods: leaves; seeds, grains, and nuts; fruit

Other Foods: fungus

Foraging Behavior: stores or caches food

Primary Diet: omnivore

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: Animal Diversity Web

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Associations

Ecosystem Roles

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.

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: BioKIDS Critter Catalog

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Predation

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.

Known Predators:

  • American minks (Mustela_vison)
  • weasels (Mustela)
  • red foxes (Vulpes_vulpes)
  • bobcats (Lynx_rufus)
  • grey wolves (Canis_lupus)
  • Canada lynx (Lynx_canadensis)
  • coyotes (Canis_latrans)
  • birds of prey (Falconiformes)
  • red-tailed hawks (Buteo_jamaicensis)

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: BioKIDS Critter Catalog

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Fungus / feeder
Sciurus carolinensis feeds on fruitbody of Russula
Other: minor host/prey

In Great Britain and/or Ireland:
Fungus / feeder
Sciurus carolinensis feeds on fruit of Corylus avellana

Fungus / feeder
Sciurus carolinensis feeds on fruit of Fagus sylvatica

Fungus / feeder
Sciurus carolinensis feeds on subterranean ascoma of Elaphomyces granulatus

Animal / dung saprobe
gregarious perithecium of Sordaria fimicola is saprobic in/on dung or excretions of dung of Sciurus carolinensis

Animal / dung saprobe
apothecium of Thelebolus nanus is saprobic in/on dung or excretions of dung of Sciurus carolinensis

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Ecosystem Roles

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.

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: Animal Diversity Web

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Predation

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.

Known Predators:

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: Animal Diversity Web

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Known predators

Sciurus carolinensis is prey of:
Mustela
Mustela vison
Lynx rufus
Lynx canadensis
Canis lupus
Vulpes vulpes

This list may not be complete but is based on published studies.
Creative Commons Attribution 3.0 (CC BY 3.0)

© SPIRE project

Source: SPIRE

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Known prey organisms

Sciurus carolinensis preys on:
fungi
Insecta
Amphibia
Aves
Mammalia
Corvus caurinus

This list may not be complete but is based on published studies.
Creative Commons Attribution 3.0 (CC BY 3.0)

© SPIRE project

Source: SPIRE

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

General Ecology

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).

Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© NatureServe

Source: NatureServe

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Life History and Behavior

Behavior

Communication and Perception

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 ; acoustic

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: BioKIDS Critter Catalog

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Communication and Perception

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 ; acoustic

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: Animal Diversity Web

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Cyclicity

Comments: 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.

Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© NatureServe

Source: NatureServe

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Life Expectancy

Lifespan/Longevity

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

Range lifespan

Status: wild:
12.5 (high) years.

Average lifespan

Status: wild:
12.5 years.

Average lifespan

Status: captivity:
23.5 years.

Average lifespan

Status: wild:
23.5 years.

Average lifespan

Status: wild:
23.6 years.

Average lifespan

Status: captivity:
12.0 years.

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: BioKIDS Critter Catalog

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Lifespan/Longevity

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

Range lifespan

Status: wild:
12.5 (high) years.

Average lifespan

Status: wild:
12.5 years.

Average lifespan

Status: captivity:
23.5 years.

Average lifespan

Status: wild:
23.5 years.

Average lifespan

Status: wild:
23.6 years.

Average lifespan

Status: captivity:
12.0 years.

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: Animal Diversity Web

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Lifespan, longevity, and ageing

Maximum longevity: 23.6 years (captivity)
Creative Commons Attribution 3.0 (CC BY 3.0)

© Joao Pedro de Magalhaes

Source: AnAge

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Reproduction

In Illinois, most breeding occurs in December-February and May-June; slightly later in more northern latitudes (see Koprowski 1994). One or two litters/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 5 months) or later. Reproductive output, including the percentage of adults that produce young and the number of litters/year, is positively correlated with mast abundance. Maximum reproductive longevity is about a decade.

Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© NatureServe

Source: NatureServe

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

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

Mating System: polygynandrous (promiscuous)

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).

Breeding interval: 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 gestation period: 44.0 days.

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.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); fertilization ; viviparous

Average birth mass: 15 g.

Average gestation period: 44 days.

Average number of offspring: 4.

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)

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: BioKIDS Critter Catalog

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

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

Mating System: polygynandrous (promiscuous)

Males start following females 5 days before estrus and may come from as far away as 500 meters. Estrus in the female is indicated by an enlarged pink vulva, a condition which usually lasts less than 8 hours. The vagina is closed in prepubescent and anestrous females. Copulation lasts less than thirty seconds. After ejaculation, a gelatinous white vaginal plug forms, preventing further sperm entry.

Breeding occurs in December-February and May-June and is slightly delayed in more northern latitudes. Gestation lasts 44 days. Most females begin their reproductive life at 1.25 years 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. Inactive testes weigh 1g, whereas active testes weight 6-7g. This cycle of testicular recrudescence and regression occurs twice a year.

Newborns are naked with the exception of their vibrissae and they weigh from 13-18g. Young are altricial. Weaning begins in the seventh week and is completed by the tenth. At this point, the juvenile pelage is lost. Adult size and mass are reached at 9 months. Two litters are born each year in late winter and midsummer with generally 2-4 young per litter (up to 8 young are possible).

Breeding interval: 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 gestation period: 44.0 days.

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.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); fertilization ; viviparous

Average birth mass: 15 g.

Average gestation period: 44 days.

Average number of offspring: 4.

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)

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: Animal Diversity Web

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Molecular Biology and Genetics

Molecular Biology

Statistics of barcoding coverage: Sciurus carolinensis

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 0
Specimens with Barcodes: 12
Species With Barcodes: 1
Creative Commons Attribution 3.0 (CC BY 3.0)

© Barcode of Life Data Systems

Source: Barcode of Life Data Systems (BOLD)

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Conservation

Conservation Status

National NatureServe Conservation Status

Canada

Rounded National Status Rank: N5 - Secure

United States

Rounded National Status Rank: N5 - Secure

Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© NatureServe

Source: NatureServe

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

NatureServe Conservation Status

Rounded Global Status Rank: G5 - Secure

Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© NatureServe

Source: NatureServe

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

IUCN Red List Assessment


Red List Category
LC
Least Concern

Red List Criteria

Version
3.1

Year Assessed
2008

Assessor/s
Linzey, A.V., Koprowski, J. & NatureServe (Hammerson, G.)

Reviewer/s
Amori, G. (Small Nonvolant Mammal Red List Authority) & Chanson, J. (Global Mammal Assessment Team)

Contributor/s

Justification
Listed as Least Concern because of its wide distribution, large population, occurrence in a number of protected areas, no major threats, and it is tolerant to habitat disturbance and its population is increasing.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© International Union for Conservation of Nature and Natural Resources

Source: IUCN

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Eastern Grey Squirrels are not threatened or in danger.

IUCN Red List of Threatened Species: least concern

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: BioKIDS Critter Catalog

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Sciurus carolinensis is not threatened.

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

IUCN Red List of Threatened Species: least concern

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: Animal Diversity Web

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Status

Introduced invasive species (3). No conservation status.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© Wildscreen

Source: ARKive

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Population

Population
This species is widespread and abundant. Reported densities vary from <3/ha in continuous woodlands to >21/ha in urban parks. Population and range are increasing (J Koprowski pers. comm.).

Population Trend
Increasing
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© International Union for Conservation of Nature and Natural Resources

Source: IUCN

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Threats

Major Threats
There are no major threats to this species.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© International Union for Conservation of Nature and Natural Resources

Source: IUCN

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

This species is a serious pest in Britain, and its habit of removing tree bark is extremely damaging. In addition to out-competing red squirrels, it also carries a disease called parapox virus, which affects the native species (5).
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© Wildscreen

Source: ARKive

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Management

Management Requirements: See Williamson (no date) for information on habitat management. An area can function as a gray squirrel management unit as long as it is 15-30 m wide and 2-4 ha in extent; a reasonable goal for managing a population for hunting in an extensive area is 1.2-2.5 squirrels/ha; 5-12 squirrels/ha may be suitable and possible where squirrels are managed for nonconsumptive recreation on smaller sites; 12-30 tree cavities/ha is a reasonable management goal (Teaford 1986, which see for further recommendations).

See Teaford (1986) for specifications for the construction and placement of wooden nest boxes and rubber tire shelters.

See also Nixon and Hansen (1987).

Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© NatureServe

Source: NatureServe

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Conservation Actions

Conservation Actions
The species occurs in a number of protected areas throughout its range.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© International Union for Conservation of Nature and Natural Resources

Source: IUCN

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Conservation

No conservation measures are in place for this introduced and now common species. Grey squirrels are controlled to protect trees and in areas where red squirrels persist (6). The eradication of grey squirrels for conservation reasons is unlikely; the costs involved would be enormous, and the species is very popular with the public (6).
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© Wildscreen

Source: ARKive

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Relevance to Humans and Ecosystems

Benefits

Economic Uses

Comments: Popular game species, with many millions harvested annually.

Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© NatureServe

Source: NatureServe

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Economic Importance for Humans: Negative

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

Negative Impacts: crop pest; household pest

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: BioKIDS Critter Catalog

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Economic Importance for Humans: Positive

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.

Positive Impacts: food ; ecotourism

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: BioKIDS Critter Catalog

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Economic Importance for Humans: Negative

In Great Britain, Sciurus carolinensis is considered very destructive to property and is ranked second in negative impact only to the Norway rat (Rattus norvegicus).

Negative Impacts: crop pest; household pest

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: Animal Diversity Web

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Economic Importance for Humans: Positive

Eastern grey squirrels 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.

Positive Impacts: food ; ecotourism

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: Animal Diversity Web

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Wikipedia

Eastern gray squirrel

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

Distribution[edit]

Sciurus carolinensis is native to the eastern and midwestern United States, and to the southerly portions of the eastern provinces of eastern Canada. The native range of the eastern gray squirrel overlaps with that of the fox squirrel (Sciurus niger), with which it is sometimes confused, although the core of the fox squirrel's range is slightly more to the west. The eastern gray squirrel is found from New Brunswick to Manitoba, south to East Texas and Florida.[1] There are breeding eastern gray squirrels in Nova Scotia, but it is not known if this population was introduced or came from natural range expansion.[3] It has also been introduced into Ireland,[4] Britain, Italy, South Africa, and Australia (where it was extirpated by 1973).[1] Eastern grey squirrels in Europe are a concern because they have displaced some of the native squirrels there.

A prolific and adaptable species, the eastern gray squirrel has been introduced to, and thrives in, several regions of the western United States. The gray squirrel is an invasive species in Britain; it has spread across the country and has largely displaced the native red squirrel, Sciurus vulgaris. In Ireland, the red squirrel has been displaced in several eastern counties, though it still remains common in the south and west of the country.[5] There are concerns that such displacement might happen in Italy and that gray squirrels might spread from Italy to other parts of mainland Europe.[6]

Etymology[edit]

The genus, Sciurus, is derived from two Greek words, skia, meaning shadow, and oura, meaning tail. This name alludes to the squirrel sitting in the shadow of its tail.[7] The specific epithet, carolinensis, refers to the Carolinas, where the species was first recorded and where the animal is still extremely common. In the United Kingdom and Canada, it is simply referred to as the "grey squirrel".

Description[edit]

Bounding tracks in concrete
Gray squirrel with brownish color – taken in Cincinnati, Ohio

As the name suggests, the eastern gray squirrel has predominantly gray fur, but it can have a brownish color. It has a usual white underside as compared to the typical brownish-orange underside of the fox squirrel.[8] It has a large bushy tail. Particularly in urban situations where the risk of predation is reduced, both white- and black-colored individuals are quite often found. The melanistic form, which is almost entirely black, is predominant in certain populations and in certain geographic areas, such as in large parts of southeastern Canada. Genetic variations within these include individuals with black tails and black-colored squirrels with white tails (see Tree squirrel for more information on these color variations).

The head and body length is from 23 to 30 cm (9.1 to 11.8 in), the tail from 19 to 25 cm (7.5 to 9.8 in) and the adult weight varies between 400 and 600 g (14 and 21 oz).[9][10]

The tracks of an eastern gray squirrel are difficult to distinguish from the related fox squirrel and Abert's squirrel, though the latter's range is almost entirely different from the gray's. Like all squirrels, the eastern gray shows four fingers on the front feet and five on the hind feet. The hind foot-pad is often not visible in the track. When bounding or moving at speed, the front foot tracks will be behind the hind foot tracks. The bounding stride can be two to three feet long.[11]

Behavior[edit]

Reaching out for food on a garden bird feeder, this squirrel can rotate its hind feet, allowing it to descend a tree head-first.

Like many members of the family Sciuridae, the eastern gray squirrel is a scatter-hoarder; it hoards food in numerous small caches for later recovery.[1] Some caches are quite temporary, especially those made near the site of a sudden abundance of food which can be retrieved within hours or days for reburial in a more secure site. Others are more permanent and are not retrieved until months later. Each squirrel is estimated to make several thousand caches each season. The squirrels have very accurate spatial memory for the locations of these caches, and use distant and nearby landmarks to retrieve them. Smell is used once the squirrel is within a few inches of the cache.[citation needed]

Squirrels have been known to use deceptive behavior to prevent other animals from retrieving cached food. They will pretend to bury the object if they feel that they are being watched. They do this by preparing the spot as usual, for instance digging a hole or widening a crack, miming the placement of the food, while actually concealing it in their mouths, and then covering up the "cache" as if they had deposited the object. They will also hide behind vegetation while burying food or hide it high up in trees (if their rival is non-arboreous). Such a complex repertoire suggests that the behaviors are not innate, and imply theory of mind thinking.[12][13]

The eastern gray squirrel is one of very few mammalian species that can descend a tree head-first. It does this by turning its feet so the claws of its hind paws are backward pointing and can grip the tree bark.[14]

Eastern gray squirrels build a type of nest, known as a "drey", in the forks of trees, consisting mainly of dry leaves and twigs. Males and females may share the same nest for short times during the breeding season and during cold winter spells squirrels may share a drey to stay warm. They may also nest in the attic or exterior walls of a house, where they may be regarded as pests, and as fire hazards due to their habit of gnawing on electrical cables (see Tree squirrel for more on interactions with humans). In addition, squirrels may inhabit a permanent tree den hollowed out in the trunk or a large branch of a tree.[15]

Eastern gray squirrels are crepuscular,[10] or more active during the early and late hours of the day, and tend to avoid the heat in the middle of a summer day.[15] They do not hibernate.[16]

Predation[edit]

Predators include humans, hawks, weasels, raccoons, foxes, domestic and feral cats, snakes, owls, and dogs.[15] In its introduced range in South Africa, it has been preyed on by African Harrier-Hawks.[17]

Reproduction[edit]

Eastern gray squirrels are born hairless with their eyes closed

Eastern gray squirrels can breed twice a year, but younger and less experienced mothers will normally have a single litter per year in the spring. Depending on forage availability, older and more experienced females may breed again in summer.[18] In a year of abundant mast crop 36% of females will bear two litters, but none will do so in a year of poor mast crop.[19] Their breeding seasons are December to February and May to June, though this is slightly delayed in more northern latitudes.[10][15] The first litter is born in February or March, the second in June or July, though, again, birthing may be advanced or delayed by a few weeks depending on climate, temperature and forage availability. In any given breeding season an average of 61 - 66% of females will bear young.[19] If a female fails to conceive or loses her young to unusually cold weather or predation, she will re-enter estrus and have a later litter.

Normally, one to four young are born in each litter, but the largest, possible litter size is eight.[19] The gestation period is about 44 days.[19] The young are weaned at around 10 weeks, though some may wean up to six weeks later in the wild. They begin to leave the nest after 12 weeks, with autumn born young often wintering with their mother. Only one in four squirrel kits will survive to one year of age, with mortality of around 55% for the following year. Mortality rates then decrease to around 30% for following years until they increase sharply at eight years of age.[19]

Eastern gray females can rarely enter estrus as early as five and a half months old,[15] but females are not normally fertile before at least one year of age. Their mean age of first estrus is 1.25 years.[19] Male Eastern Greys are sexually mature between one and two years of age.[20] These squirrels can live to be 20 years old in captivity, but in the wild live much shorter lives due to predation and the challenges of their habitat.

Communication[edit]

Squirrel standing upright.

As in most other mammals, communication among eastern gray squirrel individuals involves both vocalizations and posturing. The species has a quite varied repertoire of vocalizations, including a squeak similar to that of a mouse, a low-pitched noise, a chatter, and a raspy "mehr mehr mehr". Other methods of communication include tail-flicking and other gestures, including facial expressions. Tail flicking and the "kuk" or "quaa" call are used to ward off and warn other squirrels about predators as well as to announce when a predator is leaving the area.[21] Squirrels also make an affectionate coo-purring sound that biologists call the "muk-muk" sound. This is used as a contact sound between a mother and her kits and, in adulthood, by the male when he courts the female during mating season.[21]

The use of vocal and visual communication has been shown to vary by location, based on elements such as noise pollution and the amount of open space. For instance, populations living in large cities generally rely more on the visual signals, due to the generally louder environment with more areas without much visual restriction. However, in heavily wooded areas, vocal signals are used more often due to the presence of less noise and a dense canopy restricting visual range.[22]

Diet[edit]

Eating a peanut

Eastern gray squirrels eat a range of foods, such as tree bark, tree buds, berries, many types of seeds and acorns, walnuts, and other nuts, and some types of fungi found in the forests, including fly agaric mushrooms (Amanita muscaria).[23] They can cause damage by tearing the tree bark and eating the soft cambial tissue underneath. In Europe, sycamore (Acer pseudoplatanus) L. and beech (Fagus sylvatica L.) suffer the greatest damage.[24]

Eastern gray squirrels have a high enough tolerance for humans to inhabit residential neighborhoods and will raid bird feeders for millet, corn, and sunflower seeds. They will also raid gardens for tomatoes, corn, strawberries, and other garden crops.[25] On very rare occasions, when their usual food sources are scarce, eastern gray squirrels will also prey upon insects, frogs, small rodents including other squirrels, and small birds, their eggs and young.[1][15] They will also gnaw on bones, antlers, and turtle shells – likely as a source of minerals sparse in their normal diet.[23]

Habitat[edit]

In the wild, eastern gray squirrels can be found inhabiting large areas of mature, dense woodland ecosystems, generally covering 100 acres (40 hectares) of land.[15] These forests usually contain large amounts of dense understory vegetation that provides them sufficient amount of food sources and favorable shelters. Oak-hickory hardwood forests are preferred over coniferous forests.[10]

Eastern gray squirrels generally prefer constructing their dens upon large tree branches and within the hollow trunks of trees. They also have been known to take shelter within abandoned bird nests. The dens are usually lined with moss plants, thistledown, dried grass, and feathers. These perhaps provide and assist in the insulation of the den, used to reduce heat loss. A cover to the den is usually built afterwards.[citation needed]

Close to human settlements, eastern gray squirrels are found in parks and back yards of houses within urban environments and in the farmlands of rural environments.[26]

Introductions[edit]

The eastern gray squirrel is an introduced species in a variety of locations in western North America: in western Canada, to the southwest corner of British Columbia and to the city of Calgary, Alberta;[27] in the United States, to the states of Washington and Oregon and, in California, to the city of San Francisco and the San Francisco Peninsula area in San Mateo and Santa Clara Counties, south of the city. It has become the most common squirrel in many urban and suburban habitats in western North America, from north of central California to southwest British Columbia. At the turn of the 19th to 20th centuries, the eastern gray squirrel was introduced into South Africa, Ireland, and England.

In South Africa, though exotic, it is not usually considered an invasive species owing to its small range (only found in the extreme southwestern part of the Western Cape, going north as far as the small farming town of Franschhoek), as well because it inhabits urban areas and places greatly affected by humans, such as agricultural areas and exotic pine plantations. Here, it mostly eats acorns and pine seeds, although it will take indigenous and commercial fruit, as well.[28] Even so, it is unable to use the natural vegetation (fynbos) found in the area, a factor which has helped to limit its spread.[29] It does not come into contact with native squirrels due to geographic isolation (a native tree squirrel, Paraxerus cepapi, is found only in the savanna regions in the northeast of the country)[30] and different habitats.

It spread rapidly across England and then became established in both Wales and parts of southern Scotland. On mainland Britain, it has almost entirely displaced the populations of native red squirrels. On the island of Ireland, this displacement has not been as rapid because there was only a single introduction, in County Longford. Schemes have been introduced to control the population in Ireland to encourage the native red squirrels. Eastern gray squirrels have also been introduced to Italy, and the European Union has expressed concern it will similarly displace the red squirrel from parts of the European continent.

Displacement of red squirrels[edit]

In the United Kingdom and in Ireland, the eastern gray squirrel is not regulated by natural predators.[31] This has aided its rapid population growth and has led to the species being classed as a pest. Measures are being devised to reduce its numbers, including one plan for celebrity television chefs to promote the idea of eating the squirrels.[32] In areas where relict populations of red squirrel survive, such as the islands of Anglesey and Brownsea, programs exist to eradicate gray squirrels in an effort to allow red squirrel populations to recover.[33]

Although complex and controversial, the main factor in the eastern gray squirrel's displacement of the red squirrel is thought to be its greater fitness and, hence, a competitive advantage over the red squirrel on all measures.[34] The eastern gray squirrel tends to be larger and stronger than the red squirrel and has been shown to have a greater ability to store fat for winter. The squirrel can therefore compete more effectively for a larger share of the available food, resulting in relatively lower survival and breeding rates among the red squirrel. Parapoxvirus may also be a strongly contributing factor; red squirrels have long been fatally affected by the disease, while the eastern gray squirrels are unaffected but thought to be carriers. However, there have recently been several cases of red squirrels surviving as they have developed an immunity - although it is worth noting that their population is still being massively affected. The red squirrel is also less tolerant of habitat destruction and fragmentation which has led to its population decline, while the more adaptable eastern gray squirrel has taken advantage and expanded.

Similar factors appear to have been at play in the Pacific region of North America, where the native American red squirrel has been largely displaced by the eastern gray squirrel in parks and forests throughout much of the region.

Ironically, "fears" for the future of the eastern gray squirrel arose in 2008, as the melanistic form (black) began to spread through the southern British population.[35][36] In the UK, if a "grey squirrel" (eastern gray squirrel) is trapped, under the Wildlife and Countryside Act 1981, it is illegal to release it or to allow it to escape into the wild; instead, it should be humanely destroyed.[37]

As food[edit]

See also: Tree squirrel

Gray squirrels were eaten in earlier times by Native Americans and their meat is still popular with hunters across most of their range in North America. Today, it is still available for human consumption and is occasionally sold in the United Kingdom.[38]

See also[edit]

References[edit]

  1. ^ a b c d e Linzey, A.V., Koprowski, J. & NatureServe (2008). Sciurus carolinensis. In: IUCN 2008. IUCN Red List of Threatened Species. Retrieved 2008-11-18.
  2. ^ Thorington, R.W., Jr.; Hoffmann, R.S. (2005). "Sciurus (Sciurus) carolinensis". In Wilson, D.E.; Reeder, D.M. Mammal Species of the World: a taxonomic and geographic reference (3rd ed.). The Johns Hopkins University Press. pp. 754–818. ISBN 0-8018-8221-4. OCLC 26158608. 
  3. ^ Huynh H., Williams G., McAlpine D., and Thorington R., (2010). "Establishment of the Eastern Gray Squirrel (Sciurus carolinensis) in Nova Scotia, Canada". Northeastern Naturalist 17 (4): 673–677. doi:10.1656/045.017.0414. 
  4. ^ McGoldrick, M. and Rochford, J. (2009). "Recent range expansion by the Grey Squirrel (Sciurus carolinensis Gmelin 1788". I. Nat. J. 30: 24–28. JSTOR 20764520. 
  5. ^ Carey, M., Hamilton, G., Poole, A., and Lawton, C. (2007) The Irish Squirrel Survey 2007. COFORD, Dublin, ISBN 1902696603
  6. ^ "Summary (of Bertolino S., Lurz. P.W.W., Rushton S.P. 2006, DIVAPRA Entomology & Zoology)". Europeansquirrelinitiative.org. Retrieved 10 June 2010. 
  7. ^ Hamilton, H. (1990). Smith, D., ed. Eastern Grey Squirrel. Hinterland Who's Who. ISBN 0-660-13634-1. Retrieved 18 November 2008. 
  8. ^ "New York's Wildlife Resources". Department of Natural Resources at Cornell University. p. 2. Retrieved 28 September 2013. 
  9. ^ BBC: Science and Nature, "Grey squirrel: Sciurus carolinensis"
  10. ^ a b c d "Red & Gray Squirrels in Massachusetts". MassWildlife. Massachusetts Division of Fisheries and Wildlife. Retrieved 3 April 2012. 
  11. ^ Murie, Olaus Johan and Elbroch, Mark (2005) Peterson Field Guide to Animal Tracks, Houghton Mifflin Harcourt, p. 79, ISBN 061851743X.
  12. ^ Grant, Steve (21 October 2004) "The Squirrel's Bag Of Tricks: They Can't Get Out Of The Way Of Cars, But Other Behaviors Demonstrate Advanced Thinking (for A Rodent)", The Hartford Courant.
  13. ^ "Smart squirrels fool food thieves", BBC Home, 17 January 2008.
  14. ^ Alexander, R. McNeill (2003). Principles of animal locomotion. Princeton University Press. p. 162. ISBN 0691086788. 
  15. ^ a b c d e f g Lawniczak, M. (2002). "Sciurus carolinensis". Animal Diversity Web. Retrieved 10 July 2008. 
  16. ^ "The Grey Squirrel (Sciurus carolinensis)". Grey squirrel Advisory. Retrieved 10 July 2008. 
  17. ^ "Polyboroides typus (African harrier-hawk, Gymnogene)". Retrieved 29 June 2013. 
  18. ^ http://www.ccenassau.org/yahoo_site_admin/assets/docs/Squirrel_factsheet.209103258.pdf
  19. ^ a b c d e f Koprowski, John L. (2 December 1994). "Sciurus carolinensis". Mammalian Species 480: 1–9. Retrieved 2014-03-26. 
  20. ^ http://www.ncbi.nlm.nih.gov/pubmed/4018551
  21. ^ a b Kelly, John (April 9, 2012). "Learn to speak squirrel in four easy lessons". Washington Post. Retrieved 2014-03-07. 
  22. ^ http://www.currentzoology.org/temp/%7B9776C11E-254E-42C9-8B99-06749C919867%7D.pdf
  23. ^ a b Long, Kim (September 1995). Squirrels: a wildlife handbook. Big Earth Publishing. p. 95. ISBN 978-1-55566-152-6. 
  24. ^ Butler, F. and Kelleher, C. (eds) 2012. All-Ireland Mammal Symposium 2009. Irish Naturalists' Journal, Belfast, ISBN 978-0-956704-1-1
  25. ^ "How to Manage Pests - Tree Squirrels". University of California. Retrieved 23 May 2014. 
  26. ^ "The Leading America Zoo Site on the Net". americazoo.com. Retrieved 30 October 2011. 
  27. ^ "Hinterland Who's Who – Eastern Grey Squirrel". Hww.ca. Retrieved 10 June 2010. 
  28. ^ "The Grey Squirrel – Sciurus carolinensis of Southern Africa". Home.intekom.com. Retrieved 10 June 2010. 
  29. ^ "Sciurus carolinensis (Grey Squirrel)". Biodiversityexplorer.org. Retrieved 10 June 2010. 
  30. ^ "Tree Squirrel | Rodent | Southern Africa". Krugerpark.co.za. Retrieved 10 June 2010. 
  31. ^ http://www.forestry.gov.uk/forestry/infd-6l4fdh
  32. ^ "Jamie 'must back squirrel-eating'". BBC News. 23 March 2006. Retrieved 22 August 2007. 
  33. ^ "Red squirrel conservation, squirrel ecology and grey squirrel management". The Friends of the Anglesey Red Squirrels. Retrieved 22 August 2007. 
  34. ^ Wauters, L. A., Gurnell, J., Martinoli, A., & Tosi, G. (2002). "Interspecific competition between native Eurasian red squirrels and alien grey squirrels: does resource partitioning occur?". Behavioral Ecology and Sociobiology 52 (4): 332–341. doi:10.1007/s00265-002-0516-9. 
  35. ^ "Black squirrels set to dominate". BBC News. 20 January 2009. Retrieved 30 October 2011. 
  36. ^ "The pack of mutant black squirrels that are giving Britain's grey population a taste of their own medicine". Daily Mail (London). 26 April 2008. 
  37. ^ "Defra Rural Development Service Technical Advice Note 09". 
  38. ^ "Wild meat: Squirrel nutcase". The Economist, Vol. 402 Number 8772 (3 March 2012).

Further reading[edit]

  • Koprowski, John L. (2 December 1994). "Sciurus carolinensis". Mammalian Species 480: 1–9. Retrieved 2014-03-26. —A comprehensive survey paper, with extensive references
Creative Commons Attribution Share Alike 3.0 (CC BY-SA 3.0)

Source: Wikipedia

Unreviewed

Article rating from 0 people

Default rating: 2.5 of 5

Names and Taxonomy

Taxonomy

Comments: Individuals inhabiting the Mississippi River floodplain and delta region are smaller than individuals from adjacent areas; allozyme analyses revealed that there are differences among eastern and western populations as defined by their geographic location relative to the present channel of the lower Mississippi River (Moncrief 1993).

Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© NatureServe

Source: NatureServe

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Disclaimer

EOL content is automatically assembled from many different content providers. As a result, from time to time you may find pages on EOL that are confusing.

To request an improvement, please leave a comment on the page. Thank you!