During the Vistulian glaciation, the northern part of present-day Poland lay beneath an ice sheet. In the ice-free areas, steppe-tundra developed, dominated by grasses and other herbaceous plants, along with shrubby willows (Salix). This ‘mammoth steppe’, as it is called, provided vast grazing lands not only for the woolly mammoth (Mammuthus primigenius), but also for the woolly rhinoceros (Coelodonta antiquitatis), musk ox (Ovibos moschatus), steppe bison (Bison priscus) and reindeer (Rangifer tarandus). During the Last Glacial Maximum (26,000–20,000 years ago) the climate became especially harsh, and over large areas the steppe-tundra gave way to polar desert.