American lions (panthera leo atrox) were one of the largest carnivores during the last ice age and are thought to have become extinct about 10, 000 years ago, probably due to the extinction of their primary prey. American lions most likely looked very much like their descendants, the modern day African lion, but were on average 25% larger. Based on interpretations of various cave drawings found from this era, there is a possibility that their fur was lightly striped.
The American lion lived in wide range of the Americas from Alaska and the Yukon to as far south as Peru. The best preserved species have been found in the tar pits at Rancho La Brea, in southern California. Remains have also been found throughout the Yukon.
The oldest known lion ancestor is the panthera gombaszoegensis from the early Pleistocene era (1.5 millions years ago) Remains of this lion have been found in East Africa. Panthera youngi appeared in northeastern China about 350 000 years ago and this species most likely links the primitive lion species (panthera leo fosillis ) to the direct ancestor of the American cave lion ( panthera leo spelaea ).
Panthera leo spelaea roamed throughout Eurasia and most likely crossed over to North America during the second-last (Illinoian) glaciation and gave rise to the American lion species, which continued to move further and further south.
It is assumed that the American lion hunted in groups like the modern day lion, but it has been argued by some that they might actually have hunted in pairs. This theory is based on the fact that equal numbers of male and female species have been found scattered across certain areas.
American lions were probably as fast as modern lions and most likely hunted bison and small horses. Remains of a steppe bison were found recently with signs indicating that it had been killed by a lion . American lions were probably hunted by humans and their remains have been found preserved in the sediments of late Paleolithic campsites. Several cave drawings have also been found depicting man killing beast. These ancient cave lions probably ate their fair share of human as well, I suspect.
American lions most likely lived in caves and padded their dens with grass for insulation.