Living Organisms / Animalia / Craniata / Mammalia / Rodentia / Sciuridae / Sciurus / Species
Sciurus carolinensis - Eastern grey squirrel (Click photographs/illustrations: full picture & further details)
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General and References

Alternative Names (Synonyms)

  • Grey squirrel
  • American grey squirrel
  • Eastern gray squirrel (North America)
  • Cat squirrel (North America)
  • Migratory Squirrel (North America)
  • Gray Squirrel
  • Ecureuil gris (French)
  • Grauhörnchen (German)

Names for new-borns / juveniles

Names for males --
Names for females --

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General Appearance

Typical squirrel with slender body and long bushy tail. Mainly grey with some brown on back and grizzled grey tail B142, D30

Similar Species

  • Differentiated from Sciurus vulgaris - Eurasian red squirrel: larger and sturdier, with slightly longer skull, no ear tufts, mainly grey colouration (B142, B144, B148)
  • Differentiated from Myoxus glis - Fat dormouse: much larger size B142
Sexual Dimorphism Minimal. Heavily pigmented scrotum in sexually active male, pigmented nipples in adult female B142 (B142)

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Species Author

Debra Bourne

Major References

Husbandry references:
B151, D24

(UK Contacts)

(Further Reading)
Click image for full contents list of ELECTRONIC LIBRARY

  • --

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TAXA Group (where information has been collated for an entire group on a modular basis)

Parent Group

  • Squirrels (Rodents)

Specific Needs Group referenced in Management Techniques

  • Squirrels (Rodents)

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Husbandry Information


Individual Techniques linked in Wildpro

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Appearance / Morphology

Measurement & Weight

Length Head-body length: about 10-12ins./25-30cm (B144); about 26 cm (B148); 240-285mm (D30); 240-285 cm mean 260cm (B142).
Height --
Adult weight General 14-25oz./400-710g (B144) Weight higher early winter, lowest late spring to summer (B142).
Male 440-650g mean 532g (B142).
Female 400-720g mean 568g (B142).
New-born weight 0.4-0.6oz. / 13-17g (B144); 14-18g (B142).
Growth rate --

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General --

Skull: Slightly longer than that of Sciurus vulgaris - Eurasian red squirrel and shallower (B142, B148).


Ears: no conspicuous ear tufts (B142, D30).

Dentition (Teeth)
  • I 1/1 C 0/0 P 1-2/1, M 3/3 (B142, B147).
  • Cheek teeth rooted, low-crowned, quadrate, cuspidate. (B142, B147).
  • Deciduous lower and second upper premolars shed at 16 weeks of age; others not deciduous (B142).
Eyes Large (B147)

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Legs and Tracks

Hindfoot length: mean more than 60mm (B142)

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Long, bushy, multi-coloured as hairs banded brown black and yellow (B147, D30)

Length: 8-9.4in./20-23.5cm (B144); about 21cm (B148); 19.5-24.0cm mean 22.0cm (B142).

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Coat / Pelage

Adult Female Summer: 
  • Dorsal: overall grey, with mid-dorsal area more brown.
  • Flanks and limbs: more chestnut/russet
  • Ventral: white
  • Tail: hairs banded black and brown, indistinctly white fringed 
  • Ears: grey

Winter: thicker coat

  • Dorsal grey with midline and head more yellow-brown.
  • Tail dark grey with white fringe
  • Ears: back surface white, short tufts. 

(B142, B148, D30)

Variations (If present)
  • Dark grey and black (melanistic) individuals common in northern part of North American range 
  • Melanistic forms rare in Britain
  • Albinos rare. seen in urban areas in North America, also in England (Kent, Surrey, Sussex)
  • Erythistic (reddish) forms seen occasionally in south-east England.

(B142, B143)

  • Body moult twice yearly.
  • Spring moult: from front to back
  • Autumn moult: from back to front.
  • Ear tufts moult once yearly, with new hairs growing in late summer/autumn, through to December
  • Tail moult once yearly, with new hairs growing in late summer/autumn.


New-born / Juvenile Juvenile: Darker grey than adult, and with more brown in coat (B142)

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Neonate (New-born) Characteristics

Blind, deaf, naked (B142, B147).

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Detailed Anatomy Notes
(Summary information provided for pertinent species-specific data cross-referenced in Wildpro)

Reproductive: Four pairs of nipples. Darkly pigmented from first pregnancy onwards (B142).

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Life Stages / Natural Diet / Physiology

Reproductive Stages

Breeding Season
  • Affected by food supply and weather B142
Oestrus / Ovulation --
Gestation / Pregnancy
Parturition / Birth
  • February to July (B142)
Neonatal development
  • Birth: blind, deaf and naked.
  • 14 days: skin on back pigmented, hairs appearing. 
  • 20 days: body covered with hair.
  • 19-21 days: lower incisors erupted
  • 31-42 days: upper incisors erupted
  • 28-35: days ears open
  • 28-30 days eyes open (about 90g).
  • 7 weeks: start leaving nest, eating solid food. 
  • 8-10 weeks: weaned
  • 3-4 months: moult to adult coat.

(B142, B147)

Litter size
  • 1-9, average 3 (B147)1-4, usually 2-3 (B144); average 3, usually 2-4, range 1-7 B142
Time between Litters / Litters per year
  • 1-2 litters (B142)
Lactation / Milk Production
Sexual Maturity
  • Within one year (B147) mainly end of first year (B144), 10-12 months, rarely younger (B142).
  • Over 12 years old (pregnant female) recorded in wild and 23 years in captivity (B144, B147)

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Natural Diet

  • Seeds, plant material.
  • May eat 60-80g seeds per day (laboratory studies)


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Detailed Physiology Notes
(Summary information provided for pertinent species-specific data cross-referenced in Wildpro)

Temperature --
Pulse --
Respiration --
Faeces --
Haematology / Biochemistry --
Chromosomes 2n = 40, FNa =76 (North America) (B142)
Other --

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Feeding Behaviour

Sometimes forage on ground

Bury food (nuts, acorns) in multiple small caches

(B142, B147, B148)

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Parental Behaviour


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Social Behaviour / Territoriality

  • Density may be 5-50 per hectare
  • Home range may be only 0.5 hectare.
  • Male home range generally larger than that of female
  • Home range size affected by food supply, habitat type, population density.
  • Smaller inter-individual distances than for Sciurus vulgaris - Eurasian red Squirrel.
  • Foraging area may move in autumn due to differences in food availability 
  • Hierarchy within and between sexes
  • Fights rare, but include wrestling and chasing with biting
  • Peak aggression during breeding and dispersal
  • Groups of adults may huddle in nests, particularly in winter

(B142, B147)

Inter-specific --

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Sexual Behaviour

  • Promiscuous.
  • Little courtship.
  • Males may congregate on home range of oestrous female, and fight.
  • Mating chases of several males after one female may occur; dominant male presumed to mate with female.
  • Pair separate after mating.

(B142, B147),

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Predation in Wild

  • Pine marten, wild cat, owls, raptor (e.g. goshawk).
  • Foxes, cats, dogs while on ground.
  • Stoats may take nestlings.


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Activity Patterns

  • Arboreal, but less so than Sciurus vulgaris - Eurasian red squirrel
  • Agile at traveling along branches
  • Come to ground to forage, and to bury food
  • Do not hibernate
  • In stormy/very cold weather may remain in nest until need to leave to find food

(B142, B144, B147, B148)

  • Diurnal, with activity peaks early morning and late afternoon, but midday in colder areas in winter.
  • May feed on moonlit nights in summer and autumn


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Habitat and Range

General Habitat Type

  • Forests, parks (B144)
  • Broad-leaved woodland, mainly with many tree species and particularly mature oak-hickory forests (North America).
  • Britain: Wide range of habitats, particularly mature broad-leaved forests (oak, beech, sweet chestnut, hazel), but also mixed woodland (broad-leaved/coniferous), mature coniferous, hedgerows, parks, gardens and urban areas with mature trees.

(B51, B142, D30)

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Nests / Burrows / Shelters

  • In tree hollow (ground level to about 12 metres) or ball/dome shaped nest of leaves and twigs built in branches.
  • More than one nest 
  • Domed structure, side entrance. lines with grass and leaves 
  • Leafy platform on branches in summer

(B142, B147, B148)

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Distribution and Movement (Migration etc.)

Normal South-eastern Nearctic: eastern and central USA, south-eastern Canada (B51, B143, B147)
Occasional and Accidental --
  • Europe: Great Britain, Ireland, Northern Italy

  • South Africa

(B51, B142, B143, B147)

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Intraspecific variation

  • Five subspecies recognised in North America.
  • Size cline in North America: body mass increases further north.
  • Black squirrels in north-eastern part of North American range.


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Conservation Status

Wild Population -
  • No international conservation status (B143)

  • Important game animal in North America (B143)

  • Forestry pest in Britain and Italy (B143).

  • In Britain: introduced 19th century and early 20th century; common, increasing population and range. Pre-breeding population estimate of about 2,520,000, with 2,000,000 in England, 200,000 in Scotland, 320,000 in Wales. Population estimate of this widely-distributed species was based on a limited amount of data and considered likely to be inaccurate by up to 50% in either direction (B221).

General Legislation
CITES listing --
Red-data book listing --
Threats --
Captive Populations --
Trade --

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