White-nose syndrome, caused by the fungus Pseudogymnoascus destructans, has killed over 90% of some North American bat species, with welfare implications for millions of hibernating bats dying from energetic depletion.
White-nose syndrome causes immense welfare suffering at population scale - individual bats experience repeated arousal from hibernation torpor, creating extreme energetic stress, starvation, and dehydration. Affected bats show wing lesions, lethargy, and altered behavior including flying during daylight in winter - indicators of severe physiological distress. The scale of mortality represents one of the most significant wildlife welfare crises of the modern era. Conservation responses that protect unaffected hibernacula, study European bat resistance mechanisms, and develop deployable treatments address both the conservation and welfare dimensions of this crisis.