A challenge of studying many wildlife diseases is to understand the impact on widespread populations, and bats species are no exception. A total of 45 bat species are known in North America, with 25 of those species relying on hibernation to survive winter. Since 2006, a fungal disease called white-nose syndrome , which kills bats during hibernation, has devastated populations as it spreads across North America. In Canada, three hibernating species are listed as federally endangered, however in the US, those same three species are undergoing status assessment.

The full impact of the spreading disease was unknown; however a new study has provided insight into how devastating white-nose syndrome has become. To figure this out, a large collaborative effort was made from researchers and organizations including the North American Bat Monitoring Program, Bat Conservation International, US Fish and Wildlife Service, and the US Geological Survey. 

Researchers analyzed population data for five bat species taken between 1995 to 2018 from about 200 sites in 27 US states and two Canadian provinces. They found that three species of bats have declined by over 90 percent (Northern long-eared bat, Myotis septrentionalis; little brown bat, Myotis lucifugus; and tricolored bat, Perimyotis subflavus). Declines for the two other species studied (Indiana bat, Myotis sodalist; big brown bat, Eptesicus fuscus) we less severe, but are still of great concern.