information:extraction
Fossil record

Xiaoming Wang and Richard H. Tedford, one of the foremost authorities on carnivore evolution, proposed that the genus Canis was the descendant of the coyote-like Eucyon davisi and its remains first appeared in the Miocene 6 million years ago (Mya) in the southwestern US and Mexico. By the Pliocene (5 Mya), the larger Canis lepophagus appeared in the same region and by the early Pleistocene (1 Mya) C. latrans (the coyote) was in existence. They proposed that the progression from Eucyon davisi to C. lepophagus to the coyote was linear evolution.

C. latrans and C. aureus are closely related to C. edwardii, a species that appeared earliest spanning the mid- Blancan (late Pliocene) to the close of the Irvingtonian (late Pleistocene), and coyote remains indistinguishable from C. latrans were contemporaneous with C. edwardii in North America. Johnston describes C. lepophagus as having a more slender skull and skeleton than the modern coyote. Ronald Nowak found that the early populations had small, delicate, narrowly proportioned skulls that resemble small coyotes and appear to be ancestral to C. latrans.

C. lepophagus was similar in weight to modern coyotes, but had shorter limb bones that indicate a less cursorial lifestyle. The coyote represents a more primitive form of Canis than the gray wolf, as shown by its relatively small size and its comparatively narrow skull and jaws, which lack the grasping power necessary to hold the large prey in which wolves specialize. This is further corroborated by the coyote's sagittal crest, which is low or totally flattened, thus indicating a weaker bite than the wolves. The coyote is not a specialized carnivore as the wolf is, as shown by the larger chewing surfaces on the molars, reflecting the species' relative dependence on vegetable matter. In these respects, the coyote resembles the fox-like progenitors of the genus more so than the wolf.

The oldest fossils that fall within the range of the modern coyote date to 0.74–0.85 Ma (million years) in Hamilton Cave, West Virginia; 0.73 Ma in Irvington, California; 0.35–0.48 Ma in Porcupine Cave, Colorado, and in Cumberland Cave, Pennsylvania. Modern coyotes arose 1,000 years after the Quaternary extinction event. Compared to their modern Holocene counterparts, Pleistocene coyotes (C. l. orcutti) were larger and more robust, likely in response to larger competitors and prey. Pleistocene coyotes were likely more specialized carnivores than their descendants, as their teeth were more adapted to shearing meat, showing fewer grinding surfaces suited for processing vegetation. Their reduction in size occurred within 1,000 years of the Quaternary extinction event, when their large prey died out. Furthermore, Pleistocene coyotes were unable to exploit the big-game hunting niche left vacant after the extinction of the dire wolf (Aenocyon dirus), as it was rapidly filled by gray wolves, which likely actively killed off the large coyotes, with natural selection favoring the modern gracile morph.