White-nose syndrome caused by Pseudogymnoascus destructans is causing catastrophic bat mortality in North America and has been detected in Europe, raising welfare concerns.
Bats dying from white-nose syndrome experience a prolonged welfare harm. The fungal infection disrupts torpor, causing bats to arouse frequently and burn fat reserves. Bats that exhaust their fat reserves during hibernation emerge prematurely in winter when no insect food is available, dying of starvation and cold. The scale of mortality - millions of bats - and the prolonged nature of individual deaths make white-nose syndrome one of the most significant wildlife welfare events in recent decades.