Montana Field Guide

A large squirrel that is highly variable in color, both individually and geographically. Over most of the range, the pelage is rusty yellowish with a pale yellow to orange (or light gray to dirty white) belly and a bushy tail bordered with fulvous-tipped hairs. In the Southeast, body may be sprinkled with yellow, white, and black, with the head mostly blackish except for the whitish nose and ears. In the vicinity of the Delmarva Peninsula, color may be pure steel-gray with no fulvous (Burt and Grossenheider 1964). Melanism is not uncommon. For adults, total length is 454 to 698 mm, tail length is 200 to 330 mm, and hind foot length is 51 to 82 mm (Hall 1981). Mass is 696 to 1361 g, with an average of about 800 g. There is a total of 20 teeth. The bones fluoresce bright red under longwave ultraviolet light (unique among normal adult mammals) (Flyger and Gates 1982). The Eastern Fox Squirrel of the southeastern Coastal Plain of North America is the largest tree squirrel in the western hemisphere. (Weigl et al. 1989) reported an average mass of 1006 g in North Carolina and 962 g for 44 specimens collected in the Carolinas and northern Georgia. Western Fox Squirrels tend to be smaller (600 to 900+ g).

Larger than Sciurus carolinensis, in which adults are 383 to 525 mm in total length and 340 to 700 g; also, S. niger has four cheek teeth on each side of the upper jaw (S. carolinensis usually has five), and in S. niger the tail hairs generally are not tipped with white (Flyger and Gates 1982).

Non-migratory.

Riparian cottonwood forests. Riparian stands of box elder, green ash, plains cottonwood, and willow and town parks. More prone to open forests than S. carolinensis.

More adaptable than S. carolinensis--nuts, seeds, corn, buds, flowers, tubers, bulbs, roots, arthropods, and birds' eggs. Scatter hoards of fall mast crops in shallow holes.

Home ranges may be about 18.5 acres for adult males, 8.75 acres for adult females, 7.5 acres for juveniles, and 37.5 acres for juvenile males. Homerange size and population density determined by habitat quality and food crops.

In Montana probably 2 peaks: December to January and April to June. Variable. Young may be born from February to September. Reach sexual maturity in 10 months.