| Gray fox, Island fox|
The genus Urocyon (from the Greek word for "tailed dog") is a genus that contains two (or possibly three, see next paragraph) 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; as well as one fossil species, Urocyon progressus.
Urocyon and the raccoon dog are the only canids able to climb trees. Urocyon is one of the oldest fox genera still in existence. Evidence of the Cozumel fox, a disputed extinct or critically endangered third species, was found on the island of Cozumel, Mexico. 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.