In captivity, some species often seem to thrive, while others are often prone to breeding problems, poor health, and repetitive stereotypic behaviour. Within carnivores, for instance, the brown bear, American mink and snow leopard typically adapt well to captivity and show few signs of poor welfare, while the clouded leopard and polar bear are generally hard to breed successfully and/or to prevent from performing abnormal behaviour. Understanding the fundamental source of such differences could enable reproductive success and behavioural normalcy to be improved in zoos and breeding centres, by increasing the appropriateness of the enclosure designs and environmental enrichments offered particular species, and by allowing these to be offered pre-emptively instead of reactively. Here, we demonstrate that a significant proportion of the variation in apparent welfare between captive carnivore species stems from specific aspects of natural behaviour. We tested pre-existing hypotheses that species-typical welfare is predicted by natural hunting behaviour, general activity levels, ranging, or territorial patrolling (all activities that are constrained in captivity), by collating data on median stereotypy levels and infant mortality for multiple captive species, and then regressing these against median values for the relevant aspects of natural behavioural biology (e.g. hunts per day, proportion of flesh in the diet, home-range size, etc.). Our results revealed that instead of relating to foraging (e.g. hunting), as often assumed, carnivore stereotypy levels are significantly predicted by natural ranging behaviour (e.g. home-range size and typical daily travel distances). Furthermore, naturally wide-ranging lifestyles also predicted relatively high captive infant mortality rates. These results suggest that enclosure designs and enrichments focussing on carnivores' ranging tendencies (e.g. providing more space, multiple den sites, greater day-to-day environmental variability/novelty, and/or more control over exposure to aversive or rewarding stimuli) could be particularly effective means of improving welfare; and also, that targeting such enrichment programmes on wide-ranging species, before problems even emerge, might effectively pre-empt their development. Alternatively, species with relatively small ranges could instead be made the focus of future collections and breeding programmes, zoos phasing out wide-ranging carnivores in favour of those species inherently more suited to current or readily achievable enclosure sizes and enrichment regimes. (c) 2006 Published by Elsevier B.V.
