Enrichment and animal age, not biological variables, predict positive welfare indicators in zoo-housed carnivores

Abstract

The development of evidence-based zoo animal welfare science and the use of the 'five domains' have inspired zoos to increase animal welfare, particularly recognising positive welfare states. We tested whether natural biology (number of habitats, latitudinal range, sociality, body weight) or husbandry variables (mean age of group, group size and presence of extra enrichment) predict rates of positive welfare indicators (activity, play and engagement with the environment) in the Order Carnivora from collecting data from previously published articles. For each behaviour, species (n = 23) medians were analysed using phylogenetically informed mixed-model regression. Activity data were from 136 animals (n = 23 species), environmental interaction from 55 animals (n = 15 species) and play from 27 animals (n = 7 species). Biological variables did not predict rates of behaviour at a species or an individual animal level, but husbandry variables did. At an individual level, activity and play decreased in older animals. Activity and interaction with environment also increased with additional enrichment. This study is the first to quantify positive behaviours performed by zoo housed Carnivora and shows that they display indicators of positive welfare, if appropriate husbandry including environmental enrichment is provided.