Forget polar bears. Thegiant short-faced bear (Arctodus simus) was the true heavyweight of North America’s ancient wilderness. Standing an astonishing 3.3 meters tall on its hind legs, this extinct ...

Early humans did not live in a safe world. They shared their lands with giant bears, saber toothed cats, and massive reptiles. In Australia, marsupial lions and enormous lizards stalked the plains. In ...