The genus Urocyon is a genus contains two (or possibly three) living Western Hemisphere foxes in the family Canidae, the Gray Fox (Urocyon cinereoargenteus) and the closely-related Island Fox (Urocyon littoralis) which is a dwarf cousin of the Gray Fox;[1] as well as one fossil species, Urocyon progressus.[2]Urocyon and the Raccoon Dog are the only canids able to climb trees. Urocyon is one of the oldest fox genera still in existence. A third species, apparently close to extinction or even already extinct, is (or was, until recently) found on the island of Cozumel, Mexico.[3] The Cozumel Fox, which has not been scientifically described to date, is a dwarf form like the Island Fox but a bit larger, being up to three-quarters the size of the Gray Fox.[4]
^ Prevosti, F.J., & Rincóon, A.D. (2007). "A new fossil canid assemblage from the late Pleistocene of northern South America: the canids of the Inciarte asphalt pit (Zulia, Venezuela), fossil record and biogeography". J. Pal.81 (5): 1053–1065. doi:10.1666/pleo05-143.1.
^ Gompper, M. E.; Petrites, A. E. & Lyman, R. L. (2006). "Cozumel Island fox (Urocyon sp.) dwarfism and possible divergence history based on subfossil bones". J. Zool.270 (1): 72–77. doi:10.1111/j.1469-7998.2006.00119.x.
