White-nose syndrome has killed over 90% of some bat species in North America since 2006. The welfare of millions of bats dying from this fungal disease illuminates both individual suffering and ecosystem consequences.
White-nose syndrome causes a prolonged and distressing death in affected bats. Arousal from hibernation is energetically very costly; bats repeatedly woken by the irritation of Pseudogymnoascus destructans growing on their skin deplete winter fat stores and emerge too early, too thin to survive until insects are available in spring. Starvation after emergence causes weakness and death over days. The skin lesions from fungal growth on muzzle and wing membranes during hibernation cause physical damage affecting thermoregulation and flight. The welfare significance of this epidemic, affecting millions of highly intelligent and socially complex mammals that form mother-pup bonds and demonstrate sophisticated echolocation, is substantial. The ecological consequences through insect population release further affect ecosystem health and the welfare of other species.