Mammoth steppe

During the Last Glacial Maximum, the mammoth steppe, also known as steppe-tundra, was once the Earth's most extensive biome. It stretched east-to-west, from the Iberian Peninsula in the west of Europe, across Eurasia to North America, through Beringia (what is today Alaska) and Canada; from north-to-south, the steppe reached from the arctic islands southward to China. The mammoth steppe was cold and dry, and relatively featureless, though topography and geography varied considerably throughout. Some areas featured rivers which, through erosion, naturally created gorges, gulleys, or small glens. The continual glacial recession and advancement over millennia contributed more to the formation of larger valleys and different geographical features. Overall, however, the steppe is known to be flat and expansive grassland. The vegetation was dominated by palatable, high-productivity grasses, herbs and willow shrubs.

The animal biomass was dominated by species such as reindeer, muskox, saiga antelope, steppe bison, horses, woolly rhinoceros and woolly mammoth. These herbivores, in turn, were followed and preyed upon by various carnivores, such as brown bears, Panthera spelaea (the cave or steppe-lion), scimitar cats, wolverines and wolves, among others. This ecosystem covered wide areas of the northern part of the globe, and thrived for approximately 100,000 years without major changes, but then diminished to small regions around 12,000 years ago.

Modern humans began to inhabit the biome following their expansion out of Africa, reaching the Arctic Circle in Northeast Siberia by about 32,000 years ago.