During a great glaciation, but especially during the severe climate of late Pleistocene times, the _Alpine_ mammals were driven down from the heights into the plains and among the lower mountains and foot-hills. Thus the ibex, chamois, and argali sheep from the Altai Mountains are represented both in drawing and in sculpture by the men of the Reindeer Period. Still more remarkable is the arrival in Europe of the _Steppe Fauna_ of Russia and of western Siberia, mammals which now survive in the vast Kirghiz steppes, east of the Caspian Sea and the Ural Mountains, where the climate is one of hot, dry summers and prolonged cold winters, with sweeping dust and snow storms. These animals are very hardy, alert, and swift of foot, such as the jerboa, the saiga antelope, the wild asses, and the wild horses, including the Przewalski type, which still survives in the desert of Gobi. From this region also came the Elasmothere (_E. sibiricum_), with its single giant horn above the eyes. Very distinctive of the fauna frequenting the caverns are the small rodents, including the dwarf pikas, the steppe hamsters, and the lemmings. These animals were attracted into Europe during the 'steppe' and 'loess' periods of cold, dry climate. The advance of the great Scandinavian glaciers from the north crowded to the south the _Tundra or Barren Ground_ fauna of the arctic circle. The herald of this fauna during the First Glacial Stage was the musk-ox, which appears in Sussex, and then came the reindeer of the existing Scandinavian type. These animals are followed by the woolly mammoth (_E. primigenius_) and the woolly rhinoceros (_D. antiquitatis_) with their panoply of hair and wool which had long been developing in the north. Finally in the Fourth Glacial Stage arrived the lemming of the river Obi, also the more northern banded lemming, the arctic fox, the wolverene, and the ermine, as well as the arctic hare. These tundra mammals for a short period mingled in places with survivors of the _African-Asiatic_ fauna, such as Merck's rhinoceros and the straight-tusked elephant (_E. antiquus_). In general, they swept southward as far as the Pyrenees over country which had long been enjoyed by the African-Asiatic mammals, while the hippopotami and the southern elephants retreated still farther south and became extinct. The only survivors of the great _African-Asiatic_ fauna in Fourth Glacial and Postglacial times were the hyænas (_H. crocuta spelæa_) and the lions (_Felis leo spelæa_). The lion frequently appears in the drawings of the cavemen.