Wolves, Wolf Facts, Cougars, Cougar Facts, Coyotes, Coyote Facts - Wolves, Cougars, Coyotes Forever: "During the American megafaunal extinction event around 12,700 years ago, 90 genera of mammals weighing over 44 kilograms became extinct"............"The Late Pleistocene fauna in North America included giant sloths, short-faced bears, several species of tapirs, peccaries, the American lion, giant tortoises, American cheetahs, saber-toothed cats. llamas, at least two species of bison, the stag-moose, the shrub-ox and Harlan's muskox, 14 species of pronghorn, horses, mammoths and mastodons, the beautiful armadillo, giant armadillo, giant beavers and giant condors".............. "In contrast, today the largest North American land animal is the American bison"..........."The synergy of causes for the extinctions were climate change, overhunting and contagious diseases carried by migrating humans and their animals"