The island fox (Urocyon littoralis) is a small fox that is native to six of the eight Channel Islands of California. It is the smallest fox species in the United States. There are six subspecies of the fox, each unique to the island it inhabits, reflecting its evolutionary history. Other names for the Island Fox include coast fox, short-tailed fox, and island gray fox, Channel Islands Fox, Channel Islands Gray Fox, California Channel Island Fox and Insular Gray Fox.
Its small size is a result of island dwarfing. Because island foxes are geographically isolated they have no immunity to parasites and diseases brought in from the mainland. They are especially vulnerable to those domestic dogs may carry. In addition, Golden Eagle predation and human activities devastated fox numbers on several of the Channel Islands in the 1990s. Four island fox subspecies were federally protected as an endangered species in 2004. Efforts to rebuild fox populations and restore the ecosystems of the Channel Islands are being undertaken.
The island fox is much smaller than the gray fox, roughly the size of a house cat. It is the second smallest of all foxes after the Fennec. Typically the head-and-body length is 18 to 20 in (48 to 50 cm), shoulder height 4 to 6 in (12 to 15 cm), and the tail is 4 to 11 in (11 to 29 cm) long. This is notably shorter than the tail of the gray fox. Island foxes weigh between 2.8 and 6.2 lb (1.3 and 2.8 kg). The male is always larger than the female. The largest of the subspecies occurs on Santa Catalina Island and the smallest on Santa Cruz Island.
The island fox has gray fur on its head, a ruddy red coloring on its sides. It has white fur on its belly, throat and the lower half of its face, and a black stripe on the dorsal surface of its tail. In general the coat is darker and duller hued than that of the gray fox. The island fox molts once a year between August and November. Before the first molt pups are woolly and have a generally darker coat than adult foxes.
Ecology and behavior
Their preferred habitat is complex layer vegetation with a high density of woody, perennially fruiting shrubs. The foxes live in all of the island biomes including temperate forest, temperate grassland and chaparral. There is no island supporting more than 1,000 foxes. Island foxes eat fruits, insects, birds, eggs, crabs, lizards, and small mammals, including the deer mouse. The foxes tend to move around by themselves, rather than in packs. They are generally nocturnal, albeit with peaks of activity at dawn and dusk. Activity also fluctuates with the season; they are more active during the day in summer than they are in winter.
Humans do not intimidate island foxes as they have historically been at the top of the island food chain and had no natural predators. They are quite easy to tame and are generally docile. Island foxes communicate with each other using auditory, olfactory and visual signals. A dominant fox uses vocalizations, staring, and ear flattening to cause another fox to submit. They mark territory with urine and feces.