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Big Cypress Fox Squirrel

Sciurus niger avicennia

Listing Status

  • Federal Status: Not listed
  • FL Status: State Threatened
  • FNAI Ranks: G5T2/S2 (Globally: Demonstrably Secure, Sub sp. Imperiled/State: Imperiled)
  • IUCN Status: Not ranked

Header photo by Ralph Arwood


The Big Cypress fox squirrel is a large member of the Genus Sciurus that can reach a length of 17-27 inches (45-69 centimeters) and a weight of one to three pounds (0.5 to 1.4 kilograms). This species has a black head and back fur with buff sides and belly, white ears and nose, and a long bushy black/tan tail (Florida Natural Areas Inventory 2001, M. Tucker pers. comm. 2011).


There is little information known about this subspecies due to their limited range, secretive nature, and reluctance to be captured, therefore much of the information available for Big Cypress fox squirrels is based on fox squirrels in general. 

The diet of the Big Cypress fox squirrel primarily consists of nuts, seeds, fungi, fruit, and buds, but they will also occasionally eat animal material such as insects and bird eggs.

Both male and female Big Cypress fox squirrels mate with more than one individual. Breeding can occur at any time of the year but most breeding occurs between November and February, and April and July. Females go into estrus (heat) for only one day during which several males pursue receptive females, with dominant males mating first.  Average gestation time for a fox squirrel is 44 days and the average litter size is one or three offspring. Females can become sexually mature at eight months of age, but rarely reproduce until they are over one year old. Females can continue breeding for more than 12 years (Koprowski 1994).


big cypress fox squirrel map

The Big Cypress fox squirrel is primarily a ground-dwelling species that inhabits stands of cypress, slash pine savanna, mangrove swamps, tropical hardwood forests, live oak woods, coastal broadleaf evergreen hammocks, and suburban habitats including golf courses, city parks, and residential areas (Hafner et al. 1998; Humphrey and Jodice 1992; Jansen 2008; Munim et al. 2007; Williams and Humprey 1979). This species can be found in the southwestern tip of Peninsular Florida, in Hendry and Lee counties south of the Caloosahatchee River, Collier County, mainland northern Monroe County, and extreme western Miami-Dade County (a strip of land that is largely in Big Cypress National Preserve) (Williams and Humphrey 1979; Moore 1956; see summary in USFWS 2002).


Big Cypress fox squirrels face considerable threats to their population as their habitat is destroyed and fragmented by increased development. In Hendry County, they face additional threats due to conversion of rangeland to citrus groves, and the suppression of fire which causes the understory to grow and make the habitat uninhabitable (Ditgen and Shepherd 2007). Diseases like the Squirrel Poxvirus also pose a threat to Big Cypress fox squirrel. This virulent disease causes death in 75-100% of infected squirrels (National Park Service 2010).

Conservation and Management

The Big Cypress fox squirrel is protected as a State-designated Threatened species by Florida’s Endangered and Threatened Species Rule. Further studies are necessary to gather additional information and determine precise habitat requirements of the Big Cypress fox squirrel. 

Biological Status Review (BSR)
Supplemental Information for the BSR
Species Action Plan


Florida Natural Areas Inventory. 2001. Field guide to the rare animals of Florida.

Ditgen, R.S., J.D. Shepherd and S. R. Humphrey. 2007. Big Cypress fox squirrel (Sciurus niger avicennia) diet, activity and habitat use on a golf course in southwest Florida. American Midland Naturalist 158 (2):403-414.

Hafner, D.J., E. Yensen and G.L. Gordon, Jr. (compilers and editors). 1998. North American Rodents. Status Survey and Conservation Action Plan. IUCN/SSC Rodent Specialist Group.  IUCN, Gland, Switzerland and Cambridge, UK.  X + 171pp.

Humphrey, S.R. and P.G.R. Jodice. 1992. Big Cypress fox squirrel Sciurus niger avicennia.Pages 224-233 in S.R. Humphrey (ed.), Rare and endangered biota of Florida.  Vol. I. Mammals.  University Press of Florida. Gainesville, Florida.

Jansen, D. 2008. Big Cypress fox squirrel study preliminary report. National Park Service.

Koprowski, J.L. 1994. Sciurus niger. Mammalian Species 479:1-9. 

Moore, J.C. 1956. Variation in the fox squirrel in Florida. American Midland Naturalist 55(1):41-65.

Munim, D., R. F. Noss and J. M. Watermark. 2007. The status and distribution of Big Cypress fox squirrel, Sciurus niger avicennia.  Final Report. Study No. 24036024. University of  Central Florida, Orlando, Fl. 41pp.

National Park Service. 2010. Big Cypress Squirrel Poxvirus Information Brochure. US Department of the Interior.

U.S. Fish and Wildlife Service. 2002. Endangered and Threatened Wildlife and Plants; 12-month Finding for a Petition To List the Big Cypress Fox Squirrel. Federal Register 67(37): 8499-8503.

Williams, K.S. and S.R. Humphrey. 1979. Distribution and status of the endangered Big Cypress fox squirrel (Sciurus niger avicennia) in Florida. Florida Scientist 42:201-205.