Giant Short-Faced Bear; also known as Arctodus simus
Mountains and woodlands of North America
Pleistocene-Modern (800,000-10,000 years ago)
Size and Weight:
Up to 13 feet long and one ton
Mostly carnivorous; possibly supplemented its diet with plants
Large size; long legs; blunt face and snout
About the Giant Short-Faced Bear (Arctodus simus)
Although it's often described as the largest bear that ever lived, the Giant Short-Faced Bear (Arctodus simus) didn't quite measure up to either the modern Polar Bear or to its southern counterpart, Arctotherium. But it's hard to imagine the average megafauna mammal (or early human) worrying whether it was about to be eaten by a 2,000- or a 3,000-pound behemoth. Simply put, the Giant Short-Faced Bear was one of the scariest predators of the Pleistocene epoch, full-grown adults rearing up to heights of 11 to 13 feet and capable of running at top speeds of 30 to 40 miles per hour. The main thing that distinguished Arctodus simus from that other famous ursine of the Pleistocene epoch, the Cave Bear, is that the Giant Short-Faced Bear was slightly bigger, and subsisted mostly on meat (the Cave Bear, despite its fierce reputation, being a strict vegetarian).
Because nearly as many fossil specimens don't represent the Giant Short-Faced Bear as the Cave Bear, there's still a lot we don't understand about its everyday life. In particular, paleontologists still debate this bear's hunting style and its choice of prey: with its presumed speed, the Giant Short-Faced Bear may have been capable of running down the small prehistoric horses of North America, but it doesn't seem to have been robustly built enough to tackle larger prey. One theory is that Arctodus simus was essentially a loafer, popping up suddenly after another predator had already hunted and killed its prey, driving the smaller meat-eater away, and digging in for a tasty (and unearned) meal, much like a modern African hyena.
Although it ranged across the expanse of North America, Arctodus simus was particularly plentiful in the western part of the continent, from Alaska and the Yukon Territory down to the Pacific coast as far as Mexico. (A second Arctodus species, the smaller A. pristinus, was restricted to the southern part of North America, the fossil specimens of this lesser-known bear being discovered as far afield as Texas, Mexico, and Florida.) Contemporaneous with Arctodus simus, there was also a related genus of short-faced bear native to South America, Arctotherium, the males of which may have weighed as much as 3,000 pounds--thus earning the South American Giant-Short Faced Bear the coveted title of Biggest Bear Ever.