North American bat populations face catastrophic decline from white-nose syndrome, a fungal disease that disturbs hibernation and causes mass mortality. Understanding this crisis informs conservation welfare responses.
White-nose syndrome causes severe welfare harm to individual bats. The fungus irritates skin during hibernation, causing bats to rouse prematurely when temperatures are too cold for insect availability. Repeated rousing burns fat reserves needed for winter survival, and affected bats emerge emaciated and die of starvation or exposure. Death is slow and involves what behavioral indicators suggest is significant distress. Cave disturbance by cavers during winter also triggers premature rousing with similar effects. Research into probiotic treatments applied to cave entrances and genetic selection for disease resistance offers hope. Species recovery from such massive population crashes will take decades even with successful treatment.