ScienceDaily (Feb. 27, 2012) — Coyotes today are pint-sized compared to their Ice Age counterparts, finds a new fossil study. Between 11,500 and 10,000 years ago -- a mere blink of an eye in geologic terms -- coyotes shrunk to their present size. The sudden shrinkage was most likely a response to dwindling food supply and changing interactions with competitors, rather than warming climate, researchers say.
http://www.sciencedaily.com/releases/2012/02/120227152721.htm