The woolly mammoth is an extinct species of mammoth that lived during the Pleistocene until its extinction in the early Holocene epoch, and was one of the last in a line of mammoth species, beginning with Mammuthus subplanifrons in the early Pliocene. The woolly mammoth diverged from the steppe mammoth about 400,000 years ago in East Asia. Its closest extant relative is the Asian elephant. The appearance and behaviour of this species are among the best studied of any prehistoric animal because of the discovery of frozen carcasses in Siberia and Alaska, as well as skeletons, teeth, stomach contents, dung, and depiction from life in prehistoric cave paintings. Mammoth remains had long been known in Asia before they became known to Europeans in the 17th century. The origin of these remains was long a matter of debate, and often explained as being remains of legendary creatures. The mammoth was identified as an extinct species of elephant by Georges Cuvier in 1796.