White-nose syndrome disrupts bat hibernation physiology, causing bats to wake repeatedly during winter, burn critical fat reserves, and die from starvation before spring prey becomes available.
Bats dying from white-nose syndrome experience a prolonged decline as their energy reserves are depleted by repeated involuntary awakenings. The experience of emerging from a cave in winter - cold, hungry, and unable to find insects - and dying slowly from starvation while being unable to return to functional torpor represents significant individual suffering. Bats that emerge from caves in winter are visible evidence of this crisis: they are seen flying in daylight in subfreezing temperatures, disoriented and dying. The scale of the mortality - millions of individual animals - means this pathogen has caused more deaths in North American bats than any other documented disease event in a North American wildlife population.