Distinctive cranial features of Neanderthals included prominent brow ridges, low, sloping foreheads, a chinless and heavy, forward-jutting jaw, and extremely large front teeth. This impression is offset somewhat by the observation that the Neanderthal braincase measured on average about 1600 cc, larger than contemporary Homo sapiens. For example, their thick, squat build was adapted to maintaining body temperature under harsh climatic conditions. Large front teeth may have reflected a practice common among Eskimo populations of softening animal skins by chewing. Forceful chewing is also suggested by the heavy jaw and brow ridge, both of which serve to buttress powerful muscles.
Neanderthal phylogeny remains somewhat enigmatic, despite the relative abundance of fossil remains.
In contrast, by 125,000 years ago, European archaic Homo sapiens had diverged into the classic Neanderthal form, which persisted in some areas until 35,000 years ago. Culturally, Neanderthals are closely associated with a stone-tool tradition known as the Mousterian of the middle Paleolithic . They were proficient hunters. As in most cold environments, plant foods were probably relatively scarce and consumed only seasonally. Purported evidence of aesthetic behaviors and of religious beliefs among Neanderthals remains relatively scant and controversial, leading many experts to question the extent of their linguistic capabilities.