Eastern Fox Squirrel
Sciurus niger
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Painting by Todd Zalewski from Kays and Wilson's Mammals of North America, © Princeton University Press (2002)


Fox squirrels are a medium-sized tree squirrel with no sexual dimorphism. The dorsal pelage is buff to orange and the venter is rufous. Some varieties in the southeastern United States are black. These squirrels have 8 mammae. Tail is well furred. Ear tufts often develop in winter.

Adaptations for climbing include sharp recurved claws, well developed extensors of digits and flexors of forearms, and abdominal musculature

Range: 454-698 mm
Range: 696-1,233 g
Range Map
Taxonomic Hierarchy


Fox squirrels are found throughout the eastern and central United States, south into northern Mexico, and north into Canada. They have been introduced into urban areas in western North America as well.

Kingdom: Animalia
Phylum: Chordata
     Subphylum: Vertebrata
Class: Mammalia
    Subclass: Theria
        Infraclass: Eutheria
Order: Rodentia
    Suborder: Sciuromorpha
Family: Sciuridae
    Subfamily: Sciurinae
Genus: Sciurus
Species: Sciurus niger
  • Sciurus niger cinereus
  • Sciurus niger niger
Reproduction & Life Cycle

Females can mate with several males, but the males will compete with each other to determine who gets to mate first.

Fox squirrels can mate any time of year; this behavior peaks in December and June. Males follow females prior to estrus, smelling the perineal region. Males aggregate in the home range of a female when she begins estrus. Dominance hierarchies form among the males to determine mating privilege. Copulation lasts less than thirty seconds, and females can mate with several males. A copulatory plug forms after mating. Gestation lasts 44-45 days. Average litter size is 2-3, but litters range between 1 and 7. Young are born naked, weighing between 13-18 g. Eyes open at week 5, and young are weaned at week 8. Sexual maturity is attained at 8 months for females, 10-11 months for males. Females can produce 2 litters in a year, although 1 is the norm.

Female fox squirrels care for their young in the nest for 6 weeks. When the mother leaves her young in the nest she covers them with nesting material. Young fox squirrels disperse away from their mothers range in the fall of their first year. Male fox squirrels disperse farther and may die more as a result.

Fox squirrels have been known to live to 18 years old in captivity. Under natural conditions the average lifespan is 8 to 18 years old, though most squirrels die before they reach adulthood.

Fox squirrels have been known to live to 18 years old in captivity. Under natural conditions the average lifespan is 8 to 18 years old, though most squirrels die before they reach adulthood.

Conservation Status

Many subspecies of fox squirrels are endangered due to overhunting and destruction of mature forests.


Fox squirrels, like other tree squirrels, use trees for escaping from predators. They are fast and agile in the trees. They can readily escape predators on the ground and large birds of prey if they can seek refuge in the trees.

Fox squirrels are found in a diverse array of deciduous and mixed forest. Areas with a good variety of tree species are preferred due to variability in mast production.


Primarily arboreal and diurnal. Generally, fox squirrels are not gregarious, although they come together during the breeding season when females are in estrus. Males have larger home ranges than females. Squirrels threaten one another by an upright stance with their tail over their back, followed by a quick flick of the tail. Scent-marking is another form of intra-specific communication used by fox squirrels. Vocalizations in the form of barks and chatters, distress screams, and high-pitched whines during mating are common. Fox squirrels are serially polygynous. Mating chases involve one female and a number of males, with the successful male guarding the female to prevent others from mating with her; males do not help in the raising of young.


A wide variety of foods are taken, ranging from vegetative matter to gall insects, moths, beetles, bird, eggs, and dead fish. Acorn, hickory, walnut, mulberry, and hawthorne seeds are preferred. Food can often become limiting in the winter, so squirrels commonly cache seeds in a scattered fashion for the colder months. Nuts are opened by a levering technique of the lowering incisors, a skill at which squirrels become proficient quickly.

Other Names


  • Gwińver gellrous (Breton)
  • Cat Squirrel (English)
  • Eastern Fox Squirrel (English)
  • Fox Squirrel (English)
  • Stump-eared Squirrel (English)
  • Ardilla zorra (Spanish)
  • Sciurus niger (Spanish)

They use a variety of sounds to communicate, including barks, chatters, distress screams, and high-pitched whines during mating.

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Sources used to Construct this Page:

Encyclopedia of Life

Animal Diversity Web

  • Alden, P., F. Heath, R. Keen, A. Leventer, W. Zomlefer. 1998. National Audubon society field guide to California. New York: Alfred A. Knopf.
  • Ingles, L. 1947. Mammals of the Pacific States. Stanford, California: Stanford University Press.
  • Linsdale, J. 1946. The California ground squirrel. Berkeley and Los Angeles: University of California press.
  • MacClintock, D. 1970. Squirrels of North America. New York and Toronto: Van Nostrand Reinhold Company.
  • Whitaker, Jr., J. 1980. National Audubon society field guide to North American mammals. New York: Alfred A. Knopf.
  • Boellstorff, D., D. Owings, M. Penedo, M. Hersek. 1994. Reproductive behaviour and multiple paternity of California ground squirrels. Animal Behaviour, 47(5): 1057-1064.
  • Cato, F. 2003. "San Diego Natural history Museum Field Guide: Spermophilus beecheyi" (On-line). Accessed June 17, 2003 at http://www.sdnhm.org/fieldguide/mammals/sper-bee.html .
  • Evans, F., R. Holdenried. 1943. A population study of the Beechey ground squirrel in Central California. Journal of Mammalogy, 24(2): 231-260.

Additional Photos & Video

All photos © 2008 Rick Swartzentrover - Free for non-profit use.

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