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The island fox (''Urocyon littoralis'') is a small fox that is native to six of the eight Channel Islands of California. There are six subspecies of the fox, each unique to the island it lives on, reflecting its evolutionary history. Other names for the island fox include coast fox, short-tailed fox, island gray fox, Channel Islands fox, Channel Islands gray fox, California Channel Island fox and insular gray fox. ==Taxonomy and evolution== The island fox shares the ''Urocyon'' genus with the mainland gray fox, the species from which it is descended. Its small size is a result of insular dwarfism, a form of allopatric speciation. Because the island fox is geographically isolated, it has no immunity to parasites and diseases brought in from the mainland and is especially vulnerable to those that the domestic dog may carry. In addition, predation by the golden eagle 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, and efforts to rebuild fox populations and restore the ecosystems of the Channel Islands are being undertaken. Radio collars are being attached to foxes in an effort to track and locate the young foxes. To date these efforts have been largely successful. There are six subspecies of the island fox,〔 each of which is native to a specific Channel Island, and which evolved there independently of the others. The subspecies are:〔 * ''Urocyon littoralis littoralis'' of San Miguel Island, * ''Urocyon littoralis santarosae'' of Santa Rosa Island, * ''Urocyon littoralis santacruzae'' of Santa Cruz Island, * ''Urocyon littoralis dickeyi'' of San Nicolas Island, * ''Urocyon littoralis catalinae'' of Santa Catalina and, * ''Urocyon littoralis clementae'' of San Clemente Island. Foxes from each island are capable of interbreeding, but have genetic and phenotypic distinctions that make them unique; for example, the subspecies have differing numbers of tail vertebrae. The small size of the island fox is an adaptation to the limited resources available in the island environment. The foxes are believed to have "rafted" to the northern islands between 10,400 and 16,000 years ago. Initially, fox populations were located on the three northern islands, which were likely easier to access during the last ice age—when lowered sea levels united four of the northernmost islands into a single mega-island (Santa Rosae) and the distance between the islands and the mainland was reduced—it is likely that Native Americans brought the foxes to the southern islands of the archipelago, perhaps as pets or hunting dogs. Based on the limited fossil record and genetic distance from its gray fox ancestors, the northern island fox is probably the oldest subspecies, while the San Clemente island fox has been only resident on its island for about 3,400–4,300 years, and the San Nicolas island fox established itself as an independent group about 2,200 years ago. The Santa Catalina island fox is potentially the most recently evolved subspecies, having been on its island for about 800–3,800 years.〔 The fox did not persist on Anacapa Island because it has no reliable source of fresh water; Santa Barbara Island is too small to support the food demands of the fox. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Island fox」の詳細全文を読む スポンサード リンク
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