Urocyon littoralis was originally named Vulpes littoralis in 1857. Other common names for the island fox include coast fox, short-tailed fox, island gray fox, channel island fox, channel islands gray fox, California channel island fox, and insular gray fox. Some researchers considered Urocyon littoralis to be a conspecific or even a subspecies of Urocyon cinereoargenteus. However, full biological and historical analysis and genetic reports indicate that this species is distinct.
Predators of the island fox include man, common ravens, golden eagles, and bald eagles. Its average life span is 4 to 6 years, but some individuals may live to be 15 years old.
How these foxes came to inhabit these islands still remains in question. The island fox arrived at the northern islands (San Miguel, Santa Rosa, and Santa Cruz) about 10,400-16,000 years ago and then later spread out to the southern islands (San Nicholas, Santa Catalina, and San Clemente) about 2,200-4,300 years ago. It may have migrated to the northern island of Santa Rosa from mainland California by either rafting on natural debris or by swimming. The island was only 5.5 miles away from the coastline during a time of high glaciers and low sea levels. However, it is still unknown whether these ancestors were strong enough to swim this distance. This island later formed the present day northern Channel Islands as the rising sea level had flood the island into three smaller islands.
The history of the island fox inhabiting the southern Channel Islands is another mystery. It is theorized that they were brought over by Native Americans for the purpose of fur, pets, and religious ceremonies
(Claybourne & Collins 1995, Nowak 1999, Chapman 1999, Schmeckpepper 1999, Weston date unknown, Wilson and Reeder 1993)
Perception Channels: tactile ; chemical
Urocyon littoralis is classified as "rare/lower risk" by the IUCN and "threatened" by the State of California and is protected by the California state law. There are no more than 1,000 foxes on each island and as few as 40 foxes on the smaller islands. Since their genetic variation is low, they are susceptible to disease and the consequences of environmental changes caused by man.
In 1993, their population was monitored by park biologists on San Miguel Island. This research revealed that this population of island foxes dropped from 450 in 1994 to less than 40 today. Similar outcomes are shown on the other islands. Populations on some islands have dropped as much as 90% in the past four years. This has sparked the park biologists to start a conservation team consisting of island fox researchers, captive breeding experts, canid genetics, wildlife disease experts, veterinarians, other canid biologists, and golden eagle researchers.
Threats to the island fox include loss of habitat, habitat changes resulting from the introduction of new herbivores, competition with feral cats, diseases brought by domestic dogs, and car accidents.
Measures and programs taken into effect to protect the island fox include disease investigations, elimination of feral cats, and potential captive breeding programs. The U.S. Navy and U.S. Park Service occupy their islands in order to help protect them. This species is currently a candidate for the U.S. ESA to be classified as threatened or endangered. It is already considered endangered by the State of California. Enforcing such protection is difficult, however, because they live on small remote islands.
(Nowak 1999, Chapman 1999, Schmeckpepper 1999, Weston date unknown, Fritzell et al. 1999, IUCN 1999, Wilson and Reeder 1993, National Park Service 1999)
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: critically endangered
Native Americans used the Channel island fox for many purposes. Their fur was used for arrow-quivers, capes, blankets, and headdresses for ceremonial dances. Since they are docile in nature, they were also kept as pets. Native Americans used the island fox in their religious and ceremonial practices. They served as totems, dream-helpers, and legendary characters. Native Americans also had burials for these foxes, suggesting they were of religious importance.
Today, Urocyon littoralis are sometimes hunted.
(Collins 1991, Nowak 1999)
Island grey foxes are omnivorous, with a diet consisting mostly of insects and fruits. Their diet depends on seasonal and regional abundance of food items. Fruits and berries include manzanita, toyon, saltbush, prickly pear cactus, ice plant, and the fruits of sea-figs. They also feed on deer mice and birds. Sometimes these foxes feed on reptiles such as lizards, amphibians, land snails, and human refuse, but not as frequently since these items are not as abundant on the islands. In addition, they are known to scavenge for food on beaches along the coastline.
(Claybourne & Collins 1995, Garcelon et al. 1999, Chapman 1999, Schmeckpepper 1999, Weston date unknown)
Animal Foods: birds; mammals; amphibians; reptiles; insects; mollusks
Plant Foods: fruit
Primary Diet: omnivore
Urocyon littoralis, the island grey fox, can be found on the six largest Channel islands, about 30 to 98 kilometers off of the southern California coast in North America. These islands are Santa Catalina, San Clemente, San Nicholas, San Miguel, Santa Cruz, and Santa Rosa Islands.
(Claybourne & Collins 1995, Wayne et al. 1991, Chapman 1999, Schmeckpepper 1999)
Biogeographic Regions: nearctic (Native )
Other Geographic Terms: island endemic
Channel island foxes can be found in all types on habitats of the Channel islands. This includes valley and foothill grasslands, coastal sage/scrub, coastal bluff, sand dune areas, island chapparral, southern coastal oak woodland, island woodland, southern riparian woodland, pine forests, and coastal marshes.
(Claybourne & Collins 1995, Fritzell et al. 1999)
Terrestrial Biomes: savanna or grassland ; chaparral ; forest
Island grey foxes resemble dwarf versions of the grey fox (Urocyon cinereoargenteus). This is the smallest fox species known from the United States. Adult males weigh 2.00 kilograms on average, while adult females weigh 1.88 kilograms. Body length, including head and tail, ranges from 59 to 79 centimeters. Tail length alone ranges from 11 to 29 centimeters. Height at the shoulder is from 12 to 15 centimeters.
Fur is greyish-white and black with cinnamon underfur on the dorsal side, and with pale white, yellow, and rusty-brown on the ventral surface. The chin, lips, nose, and areas around the eyes are lined in black while the sides of the rostrum are grey. The ears, neck, and sides of the limbs are cinnamon-colored. The tail has a contrasting thin black stripe on the dorsal side with a mane of stiff hairs. The underside of the tail is a rusty color. Fur color may differ among islands and be highly variable among individuals, ranging from overall greyish to honey brown and red. Island grey foxes molt once a year during the fall months from August to November. At that time, the fur coat fades in color and the fur tips curl at the ends.
Young foxes tend to have a paler but thicker dorsal fur coat compared to adults. In addition, the ears are darker in color compared to adult foxes.
(Claybourne & Collins 1995, Crooks 1994, Chapman 1999, Schmeckpepper 1999, Weston date unknown, Fritzell et al. 1999)
Range mass: 1 to 2 kg.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: male larger
Since there is little sexual dimorphism and relatively equal sex ratios in population, it is suggested that this species forms monogamous bonds.
Mating System: monogamous
Mating season of island grey foxes occurs from January to April, depending on latitude.
After mating, female foxes give birth to a litter of kits in 50 to 63 days. Although average litter size is 2 to 3 kits, it can range from 1 to 5 kits.
These kits are born in dens. Dens include ground holes, hollow trees, rock piles, shrubs, caves, and man-made structures. These dens are usually found, not made by the fox. However, if the fox is unable to find an appropriate den, she will dig a hole in the ground. The den serves to protect the kits from harsh weather, predators, and other dangers.
Kits are born blind, weighing approximately 100 grams. They reach adult weight by their first winter. They depend on their mother for milk during the first 7 to 9 weeks. Around May to June, after being weaned, they emerge from their dens and forage for food with their parents. Both parents take care of the kits. An interesting observation is that when both parents and kits are caught in traps while foraging, the parents still care for the kits and provide food to them.
Fox kits remain with their parents during the summer but become independent by September. Young foxes usually stay around the den area while the parents disperse from it. They reach sexual maturity at about 10 months old. Island foxes are able to breed after one year of age.
(Claybourne & Collins 1995, Crooks 1994, Crooks & Van Vuren 1996, Garcelon et al. 1999, Nowak 1999, Chapman 1999, Schmeckpepper 1999, Weston date unknown, Fritzell et al. 1999)
Range number of offspring: 1 to 5.
Average number of offspring: 2.5.
Range gestation period: 50 to 63 days.
Key Reproductive Features: gonochoric/gonochoristic/dioecious (sexes separate); sexual
Average number of offspring: 2.6.
Average age at sexual or reproductive maturity (female)
Sex: female: 365 days.
Parental Investment: altricial ; extended period of juvenile learning
