Both the word “cave” and the scientific name spelaeus are used because fossils of this species were mostly found in caves. This reflects the views of experts that cave bears may have spent more time in caves than the brown bear, which uses caves only for hibernation.
The cave bear had a very broad, domed skull with a steep forehead. Its stout body had long thighs, massive shins and in-turning feet, making it similar in skeletal structure to the brown bear.Cave bears were comparable in size to the largest modern-day bears. The average weight for males was 350 to 600 kg (770 to 1,320 lb),though some specimens weighed as much as 1000 kg (2,200 lb), while females weighed 225 to 250 kg (495 to 550 lb). Of cave bear skeletons in museums, 90% are male due to a misconception that the female skeletons were merely “dwarfs”. Cave bears grew larger during glaciations and smaller during interglacials, probably to adjust heat loss rate.
Cave bears of the last Ice Age lacked the usual two or three premolars present in other bears; to compensate, the last molar is very elongated, with supplementary cusps. The humerus of the cave bear was similar in size to that of the polar bear, as were the femoraof females. The femora of male cave bears, however, bore more similarities in size to those of kodiak bears.
(From Wikipedia, May 2018)