Illustration of a giant beaver (Castoroides ohioensis). This is an extinct species of beaver that lived in North America during the Pleistocene era, which spanned from 2.6 million to 11,700 years ago. These beavers were massive, growing up to 2.4 meters in length and weighing up to 100 kilograms, which is about the size of a modern black bear. Compared to modern beavers, the giant beaver had much larger hind feet and shorter hind legs. Their teeth were also much larger, up to 15 centimetres long, and had blunt, rounded tips, which is different from the chisel-like tips found in modern beavers.