Whole genome sequencing indicates that Urocyon is the most basal genus of the living canids.

[8] Fossils of what is believed to be the ancestor of the gray fox, Urocyon progressus, have been found in Kansas and date to the Upper Pliocene,[9] with some undescribed specimens dating even older.

[11] In September 2023, a live Cozumel fox was rescued from a road and subsequently released.

No skins or complete skulls of the Cozumel fox exist in any museum exhibitions, so scientists have mainly examined sub-fossils collected during archaeological excavations of Mayan civilizations who inhabited the island about 1,500–500 years ago.

Upon evaluating bones from about 12 adult individuals, scientists have concluded that the Cozumel fox is extremely small – approximately 60-80% the body size of other mainland specimens.