These lithic groups were the first inhabitants of the Patagonia region of Chile and Argentina, at the southern extreme of South America, where they lived in the harsh conditions of the sub-Antarctic climate. The melting of the Pleistocene ice layers formed rivers and lakes and opened migration routes that were extended further by a sea level lower than that of the present day. The predominantly warm, dry climate led to the formation of steppe plant life and open woodland, creating a suitable habitat for a variety of herbivores, including both extinct and modern species.