Cadomin Cave is one of the biggest caves in the Canadian Rockies. It’s also the largest known bat hibernaculum in Alberta. Every fall, bats return to this giant cave to hibernate. And every winter, bat biologists Lisa Wilkinson and Dave Hobson visit the cave to count the sleeping bats.

Why? They are looking for signs of white-nose syndrome. This deadly fungus has killed seven million bats since 2006. It’s the fastest population drop among mammals ever documented.