White-nose syndrome caused by Pseudogymnoascus destructans fungus has killed millions of North American bats, representing a catastrophic welfare crisis demanding urgent conservation response.
White-nose syndrome causes bats to wake repeatedly during hibernation, depleting fat reserves until starvation and energy failure cause death. The welfare dimension of this mass mortality event involves billions of individual animals experiencing a prolonged dying process during what should be an energy-conserving winter dormancy. The scale of mortality is almost incomprehensible, and the ecological cascade effects including insect population increases affecting both crop welfare and human health add urgency beyond individual bat welfare. Probiotic and biocontrol research offers genuine hope, with North American bat populations having natural variation in susceptibility that could support selective recovery.