The Gray Fox: The Fox That Climbs Trees

In much of the United States, the fox in the woodlot is not a red fox. The gray fox (Urocyon cinereoargenteus) is common from southern Canada to Venezuela, and it is a genuinely different animal — older, stockier, more arboreal and more herbivorous than the red fox that gets all the attention.

Identification#

The rusty neck and flanks are why so many gray foxes are reported as red foxes. Ignore colour on the sides of the animal and look at two things: the black stripe down the tail ending in a black tip, and the absence of black stockings on the legs.

The tree climbing#

Gray foxes have strongly hooked, semi-retractile claws and rotating forearms that let them grip a trunk and shin upwards, then move between branches. They climb to escape coyotes and dogs, to rest during the day, to reach fruit, and occasionally to den in hollow trunks several metres above the ground.

An ancient lineage#

Genetically, Urocyon sits at the base of the canid family tree, having diverged 8–12 million years ago — earlier than the split between true foxes and wolf-like canids. In other words, a gray fox is no more closely related to a red fox than it is to a wolf. It merely looks the part, another case of the fox body plan being a good solution to a common problem. See foxes of the world for the wider family.

Diet#

Gray foxes are the most omnivorous canids in North America. Small mammals — cotton rats, voles, mice, rabbits — form the backbone, supplemented heavily by insects, birds and, in late summer and autumn, an enormous quantity of fruit: persimmon, grape, blackberry, apple, juniper and corn. In some southern studies, plant material dominates autumn scat outright.

• Spring: rodents, nesting birds, insects.
• Summer: insects heavily, plus rodents, and early fruit.
• Autumn: fruit, mast, persimmon; the most plant-dominated season.
• Winter: rodents, rabbits, carrion.

Range, habitat and status#

Gray foxes prefer wooded and brushy country — deciduous forest, chaparral, riparian corridors, and the edges between woodland and farmland. They are far less willing to use open ground than red foxes, and correspondingly less common in suburbs, though they occur in wooded neighbourhoods across the southern and eastern United States.

The species is listed as Least Concern and remains widespread, but two pressures are worth noting: canine distemper, which causes periodic local die-offs, and coyote expansion, which suppresses gray fox activity in open habitat and pushes them further into cover. The island fox of California's Channel Islands is a dwarfed close relative in the same genus.

If you are trying to work out which fox is using your woodlot, the ground helps: gray fox tracks are smaller and blunter than red fox tracks and often disappear at the base of a tree — see fox tracks and field signs.

Denning and family life#

Gray foxes den in places other canids cannot reach: hollow logs, rock crevices, brush piles, cavities under root plates, and occasionally tree hollows several metres above the ground. They dig less than red foxes and take over less, preferring natural cavities that already offer cover.

The breeding cycle broadly parallels the red fox — mating in late winter, gestation of about 53 days, litters of three to five pups born in spring, and independence by autumn — but gray foxes are more strictly monogamous in the field and the male's provisioning role is well documented. Pups begin climbing at around three months, which is the earliest and clearest sign of which species you are watching.

For the wider family, foxes of the world places Urocyon among the true foxes, and if you are in coyote country, fox vs coyote covers the third animal that gets into these identification arguments.