Via Scientific American:
"We think that the Tibetan Plateau may be a cradle for the origins of some of the Ice Age giants," said study author Xiaoming Wang, a curator of vertebrate paleontology at the Natural History Museum of Los Angeles. Such large, furry mammals ruled the world during Earth's cold snap from 2.6 million to about 12,000 years ago. "It just happens to have the right environment to basically let animals acclimate themselves and be ready for the Ice Age cold."