Free-roaming cats affect wildlife welfare through predation and also transmit Toxoplasma gondii with potential welfare implications for other species.
The welfare effects of feline toxoplasmosis extend beyond cats to the many species they infect. Sea otters dying from toxoplasmosis experience neurological deterioration and weakness before death. Infected rodents with reduced predator fear die from increased predation. The ecological welfare chain connecting domestic cats to marine mammal mortality through watershed contamination represents a significant and underappreciated welfare harm. Keeping cats indoors prevents both toxoplasmosis transmission and direct predation wildlife welfare impacts.