Some species — ring-tailed lemurs and snow leopards, for example — apparently thrive in captivity, whereas others, such as Asian elephants and polar bears, are prone to problems that include poor health, repetitive stereotypic behaviour and breeding difficulties. Here we investigate this previously unexplained variation in captive animals' welfare by focusing on caged carnivores, and show that it stems from constraints imposed on the natural behaviour of susceptible animals, with wide-ranging lifestyles in the wild predicting stereotypy and the extent of infant mortality in captivity. Our findings indicate that the keeping of naturally wide-ranging carnivores should be either fundamentally improved or phased out.