The island fox (Urocyon littoralis) is the largest of the Channel Islands' native mammals. A descendent of the mainland gray fox, the island fox evolved into a unique species over 10,000 years ago. The island fox has similar markings to its ancestor, but is one-third smaller.

Environmental and ecological factors such as drought or food scarcity may have contributed to the natural selection for a smaller size. At 12 to 13 inches in height and 4 to 5 pounds, the island fox is about the size of a housecat. Island foxes have gray coloring on the back, rust coloring on the sides, and white underneath. The face has a distinctive black, white, and rufous-colored patterns.

Scientific Classification & Taxonomy

The scientific name of the Island fox is Urocyon littoralis. It shares the genus with its mainland ancestor the gray fox, Urocyon cineroargenteus. Littoralis translates from Latin as "situated or growing on or near a shore especially of the sea." Island foxes are distributed as six different subspecies, one on each of the six Channel Islands on which they occur. Foxes from separate islands are still capable of interbreeding, but are physically and genetically distinct enough to be recognized as separate subspecies. For example, the average number of caudal (tail) vertebrae differs significantly from island to island. Subspecies are named for their island of origin.

Island Fox Subspecies

Urocyon littoralis littoralis San Miguel Island Fox
U. littoralis santarosae Santa Rosa Island Fox
U. littoralis santacruzae Santa Cruz Island Fox
U. littoralis dickeyi San Nicolas Island Fox
U. littoralis catalinae Santa Catalina Island Fox
U. littoralis clementae San Clemente Island Fox

Taxonomy is the orderly classification of living things in terms of their relationships with one another. Here is how the island fox relates to other animals.

Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Canidae
Genus: Urocyon
Species: Urocyon littoralis

Island Fox Fossil Record

The fossil record shows evidence of foxes on Santa Rosa Island dating back 10,400 to 16,000 years ago. How did the gray fox get across the water barrier of Santa Barbara Channel? The most plausible and accepted theory is one of "rafting." During the last Ice Age, as the ocean levels lowered and the distance between the mainland and the islands shrunk, the northern islands became one large island called "Santarosae." The gray fox could have rafted on debris propelled by storms and/or currents. As the climate warmed and the ocean levels began to rise, Santarosae became the islands of Anacapa, Santa Cruz, Santa Rosa, and San Miguel. Due to the lack of a fresh water source, the foxes did not persist on Anacapa, but the other three islands had suitable habitat for foxes.

Island foxes were probably brought to the southern Channel Islands of Santa Catalina, San Nicolas, and San Clemente by the Chumash native people who traded with the Gabrielino people of the southern islands. The Chumash considered the fox to be a sacred animal--a pet of the sun, and possibly a dream helper. The island Chumash performed a fox dance and probably used the pelts of foxes to make articles like arrow quivers, capes, and headdresses.

Island Fox Habits and Behavior

Island foxes communicate with one another through sight, sound, and smell. Visually, island foxes show signs of dominance or submission through facial expressions and body posture. They communicate auditorily by barking and sometimes growling. Their keen sense of smell plays an important role in the marking of territories. Island foxes are known to scent-mark their territories with a few drops of urine and tend to concentrate scats in particular areas, often conspicuously positioned on well-traveled paths. Island fox tracks are similar to those of the gray fox only smaller.

Compared with the gray fox, island foxes are relatively diurnal (active during daylight hours) with peaks in activity occurring at dusk and dawn. Island fox diets consist primarily of fruits from plants like the sea fig, insects like the Jeruasalem cricket, and one of the few small mammals found on the islands, the deer mouse. Occasionally, foxes forage along the shoreline for crabs and other marine invertebrates.

Island Fox Reproduction

Island foxes are generally monogamous (mate for life), and breed only once a year. Pairs are seen together frequently beginning in January, and mating takes place in late February to early March. The gestation period is thought to be similar to the gray fox, which is around 52 days, and pups are born from late April through early May. Litter size ranges from one to as many as five pups, but two or three is considered average. Born in the protection of a den, pups are blind and helpless with short dark brown hair at birth. They emerge from the den at about one month of age, much furrier but still considerably darker than adults. They begin to resemble their parents by late summer.

It is believed that island fox pups undergo a period of extended parental care. In a recent study of island foxes, scientists found adults and pups in the same trap on 22 occasions. In 24 traps containing only pups, they found killed mice and other prey items outside the traps, apparently left by the parents for their young. As with most wild canids, males play an important role in the rearing of young.