Status of animal welfare research in zoos and aquariums: Where are we, where to next?

Research into the conditions that promote good animal welfare is essential to equip zoos and aquariums with the knowledge to create environments in which animals thrive. In order to collate the empirical information that is available regarding animal welfare in zoos and aquariums with regard to topics, methods and species, a systematic literature review was conducted of the primary peer-reviewed journals publishing zoo-based and welfare-based research. Journals included Animal Welfare, Animals, Applied Animal Behaviour Science, International Zoo Yearbook, Journal of Applied Animal Welfare Science, Journal of Zoo and Aquarium Research, and Zoo Biology. The literature review spanned 2008–2017 and revealed that 7.6% (n=310) of reviewed publications (n=4,096) in these journals were zoo- or aquarium-based and animal-welfare focused. The main topics studied included enrichment, social conditions and enclosure design, while understudied topics included the welfare of ambassador animals, and the welfare impacts of sound and light. Behaviour was by far the dominant welfare parameter used and the use of hormonal measures declined over this period. Taxonomic representation in these publications was notably skewed. Mammals were the focus of 75% of studies, and 82% of studies were vertebrate-focused (great apes being the dominant taxa). This study considers potential reasons for these patterns and highlights research areas for future emphasis that could serve to fill gaps in current knowledge regarding zoo and aquarium animal welfare, including more research into affective states that underlie an animal’s welfare status.