Cave Bear Molar cast. (Ursus spelaeus). Pleistocene 5.3 MYA to 24,000 years ago. Cave Bears lived in Asia and Europe. The first Cave Bear fossils were discovered in 1774, before we knew and understood fossils. Scientists thought they may belong to dragons, polar bears, or maybe an ape. A large male Cave Bear weighed in at 817 kg (1800 lbs). A big polar bear weighs 700 kg (1543 lbs). Cave Bears appear to have eaten mostly plants but also ate meat. Molar Length: 5 cm.