The only carnivores endemic to California, island foxes are separated from foxes on the mainland by 16,000 years of evolution. At that time, the northern Channel Islands were a single super-island because of the low level of the ocean.


Santa Cruz Island split off about 11,500 years ago, followed by the separation of San Miguel and Santa Rosa islands some 2,000 years later. Foxes from San Miguel Island were probably brought to the southern Channel Islands by native Americans some 2,200 to 4,300 years ago.

Once isolated from the mainland, the island fox evolved into a new and unique subspecies on each island. A small, delicate animal weighing less than five and a half pounds, the island fox is the largest native terrestrial animal on the islands.


The island fox is now in cataclysmic decline and hovering on the brink of extinction. A petition has been filed seeking protection for four of the six subspecies of island fox, yet the government agency charged with protecting endangered species-the U.S. Fish & Wildlife Service-refuses to protect the fox, using its self-imposed moratorium on listing endangered species as an excuse.

Factors contributing to the fox's decline include the recent colonization of the islands by golden eagles, which prey upon the fox; introduction of canine distemper via domestic dogs; habitat fragmentation associated with development; and loss of historic habitat caused by introduced livestock and game species. Colonization of the islands by golden eagle was facilitated by the decline and extirpation of their natural competitor, the bald eagle-which eats primarily fish. Golden eagles have also benefited from the additional prey base offered by introduced feral pigs.

The San Miguel island fox had dropped from a historic population of about 450 to 15 individuals, with only five males, by 1999. In desperation-to stave off extinction-biologists with the Institute for Wildlife Studies and Channel Islands National Park moved 14 of the foxes into protective pens. Only one San Miguel island fox remains in the wild. The Santa Rosa, Santa Cruz, and Santa Catalina subspecies have also experienced dramatic declines.


In June 2000, the Center for Biological Diversity and the Institute for Wildlife Studies filed a formal petition with FWS to list four of the six subspecies of the island fox as "endangered" under the Endangered Species Act- U. l. littoralis, U. l. santarosae, U. l. santacruzae, and U. l. catalinae.

In December 2000, the Center formally notified the U.S. Fish & Wildlife Service that it would file suit for the agency's failure to process the petition. Despite the dire status of the foxes, FWS refuses to process the petition, citing its illegal, self-imposed moratorium on protecting new species under the Act.


The plight of the island fox-which is far closer to extinction than many plants and animals already listed under the ESA-is similar to that of many Pacific Island species. The combined effects of exotic species introduction, habitat loss, predation, and habitat fragmentation can drive native species extinct at an exponential rate. Islands are places of concentrated extinction; for instance, about ninety percent of all bird species that have gone extinct over the last 400 years were island dwellers. The study of evolution and extinction on islands, known as island biogeography, has offered much to the field of conservation biology. Habitat fragmentation occurring on continental mainlands as a result of human activities functions very much as do isolated islands in an ocean; species located in these fragments become more vulnerable to extinction because of the same factors that have spelled doom for their island cousins.


graphic Andrew Rodman ©2002
July 3, 2003
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