Chytridiomycosis — caused by the chytrid fungus Batrachochytrium dendrobatidis — has driven over 90 amphibian species to extinction and causes mass mortality events with significant individual welfare implications.
The individual welfare of amphibians dying from chytridiomycosis involves a prolonged period of deterioration — affected animals become lethargic, adopt abnormal postures (sunbathing behaviour suggesting temperature-seeking to slow fungal growth), and show electrolyte imbalance signs before death. Whether amphibians experience suffering in a morally significant sense is uncertain, but their sentience evidence is sufficient to warrant precautionary concern — particularly at the scale of billions of individuals affected across thousands of species. The welfare dimension of mass amphibian die-offs is rarely discussed but represents a potentially enormous source of animal suffering that is invisible to most people.