The gray fox (Urocyon cinereoargenteus) is a mammal of the order Carnivora ranging throughout most of the southern half of North Americafrom southern Canada to northern Venezuela and Colombia. This species and the closely related Island Fox are the only living members of the genus Urocyon, which is considered to be among the most primitive of the living canids. Though it was once the most common fox in the east, human advancement allowed the red fox to become dominant. The Pacific States still have the gray fox as a dominant.
The gray fox is distinguished from most other canids by its grizzled upper parts, strong neck and black-tipped tail, while the skull can be distinguished from all other North American canids by its widely separated temporal ridges that form a U-shape. There is little sexual dimorphism, save for the females being slightly smaller than males. The gray fox ranges from 800 to 1125 mm (31.5 to 41.3 inches) in length. Its tail measures 275 to 443 mm (10.8 to 17.5 inches) and its hind feet measure 100 to 150 mm (4.9 to 5.9 inches). It weighs 3.6 to 6.82 kg (7.9 to 15 lbs). It is readily differentiated from the red fox by the lack of “black stockings” that stand out on the latter.
The gray fox’s ability to climb trees is shared only with the Asian raccoon dog among canids. Its strong, hooked claws allow it to scramble up trees to escape predators such as the domestic dog or the coyote, or to reach tree-bound or arboreal food sources. It descends primarily by jumping from branch to branch, or by descending slowly backwards as a house cat. The gray fox is nocturnal or crepuscular and dens in hollow trees, stumps or appropriated burrows during the day.
The gray fox is a solitary hunter and is largely omnivorous. It frequently preys upon the Eastern Cottontail (Sylvilagus floridanus), though it will readily catch voles, shrews, and birds. The gray fox supplements its diet with whatever fruits are readily available and generally eats more vegetable matter than does the Red Fox (Vulpes vulpes).
(From Wikipedia, September 28th, 2010)
Gray foxes are adept at climbing trees. They are active at night and during twilight, sleeping during the day in dense vegetation or secluded rocky places. Nursing mothers and pups use a den— a hollow log, abandoned building, tangle of brush, or cracked boulder—for shelter. When she is nursing small pups, the female stays within a few hundred meters of the den, but otherwise adults may range over a 2—5 square km area. Pups begin to forage on their own at about four months of age, and maintain close ties with the mother until they are about seven months old. By about ten months, both males and females are old enough to reproduce, and most females will have a litter annually from then on.
Gray foxes occur throughout most of the southern half of North America from southern Canada to northern Venezuela and Colombia. They do not occur in portions of the mountainous northwestern United States, the Great Plains and eastern Central America.
Gray foxes are solitary hunters and eat a wide variety of food. The most important food source for gray foxes is probably the eastern cottontail (Sylvilagus floridanus), but arvicolinae, Peromyscus, soricidae, and aves are readily captured and eaten. Gray foxes supplement their diet with whatever fruits are readily available and generally eat more vegetable matter than red foxes (Vulpes vulpes)
(From EOL via ADW, September 28th, 2010)