White-nose syndrome has resulted in millions of bat deaths in North America since its introduction in the early 2000’s. Infection increases the number of arousals from hibernation in susceptible bats, depleting the vital fat reserves bats need to survive the winter. The causative pathogen has a Holoarctic distribution, yet mortality is rare in Eurasia despite widespread infection in many species. We explore various factors, such as ecology, hibernation behaviour, immune responses, phylogenetics, evolution, and protective microbiomes, that may contribute to the differences seen in susceptibility between species and continents.