 The stoat thrived during the Ice Age, as its small size and long body allowed it to easily operate beneath snow, as well as hunt in burrows.The stoat and the long-tailed weasel remained separated until 500,000 years ago, when falling sea levels exposed the Bering land bridge.Combined phylogenetic analyses indicate the stoat's closest living relative is the mountain weasel ("Mustela altaica"), though it is also closely related to the least weasel ("Mustela nivalis") and long-tailed weasel ("Mustela frenata").