It appears that the Ussurian tube-nosed bat hibernates in a den made in the snow. It is the second known mammal to do this (the other is the polar bear).
Evidence for Ussurian tube-nosed bats (<i>Murina ussuriensis</i>) hibernating in snow
Evidence for Ussurian tube-nosed bats (<i>Murina ussuriensis</i>) hibernating in snow