Herds of megafauna, such as mammoth and bison, have roamed the prehistoric plains in what is today's Central Europe for several tens of thousands of years. As woodland expanded at the end of the last Ice Age, the numbers of these animals declined, and by roughly 11,000 years ago, they had completely vanished from this region. Thus, the growth of forests was the main factor that determined the extinction of such megafauna in Central Europe.