The Ussurian tube-nosed bat hibernates in snowbanks

12.21.21
A Ussurian tube-nosed bat in the snow. Photo by Yushi & Keiko Osawa.

When winter’s grip lessens and snowbanks start to melt, intrepid observers on Honshu and Hokkaido in northern Japan might occasionally notice a bat laying atop a melting snowbank. These Ussurian tube-nosed bats (Murina ussuriensis) are waking up after a winter’s slumber deep within the snowbank.

Found in some parts of Japan, Siberia, and Korea, these insectivorous bats weigh 4 to 8 grams. They are one of only two mammals (along with polar bears) known to hibernate in the snow. Providing good insulation, the snow also helps protect the bats from predators. While some predators may search hollow tree cavities and other places where bats winter, few dig deep into the snow in search of these small mammals.

Photo by Yushi & Keiko Osawa.

Dr. Hirofumi Hirakawa, wildlife biologist for the Forestry and Forest Products Research Institute in Japan, is one of the key researchers analyzing this species. He first began investigating Ussurian tube-nosed bats in 2005 when he heard reports about bats being found atop melting snow banks in the spring. He dove into academic journals, old newspaper articles, and museum collections to learn everything he could. He found notes dating back to 1964 that mentioned the species, though he couldn’t find too much information. He also kept an eye out for the bats. When people heard he was looking for the elusive snow bats, they began helping him look for them, and Dr. Hirakawa eventually found his first one several years later, located just 500 feet from his office.

While the bats often look like they’re in rough shape when they’re found, they typically rouse themselves and fly away after dark. Researchers studying the bats would wait until nightfall to observe what would happen to the bats found atop snowbanks. They were able to observe 23 individual bats until sunset, and noted 22 left soon after darkness, looking for a roosting spot, while one did not survive. Dr. Hirakawa and ecologist Yu Nagasaka studied the bats, collecting data and publishing their findings in a Scientific Reports article in 2018. They are now looking to examine the bats early in the season to weigh them and compare that data with measurements from the spring to learn about how they use energy. As researchers seek to learn as much as they can about this species, the Ussurian tube-nosed bat helps everyday observers see snowbanks in a whole new light.