White-nose syndrome, caused by the fungus Pseudogymnoascus destructans, has killed millions of hibernating bats across North America — causing mass mortality events with significant welfare implications.
White-nose syndrome causes death through starvation and cold exposure — bats that exhaust their fat reserves during winter arousals leave hibernacula to search for unavailable food, dying in cold conditions unable to fly effectively. The welfare burden of this process — progressive weakness, cold stress, starvation — affects millions of individual bats per year across affected species. The ecological consequences compound the individual welfare harms: insectivorous bats provide billions of dollars of agricultural pest control services annually, and their decline increases insect pressure on crops and humans. Individual bat deaths from WNS involve genuine suffering through the starvation process, making the scale of mortality welfare-relevant beyond its ecological and economic significance.