Lemos de Figueiredo, R., Hartley, M., Fletcher, A. W. 2021. Assessing the behaviour, welfare and husbandry of mouse deer (Tragulus spp.) in European zoos. Applied Animal Behaviour Science 237, 105283.

Mouse deer are primitive, forest ungulates found in Asia and Africa. Both the lesser mouse deer (Tragulus javanicus) and the Philippine mouse deer (T. nigricans) are managed in European zoos, but inconsistent breeding success between institutions, high neonatal mortality and a general lack of research on their husbandry and behaviour were identified by the coordinators of the European Endangered Species Programme (EEP) and the European Studbook (ESB) for each species, respectively. This study is the first to provide a behavioural description for the Philippine mouse deer and to compile a detailed behavioural repertoire for both species. Our aim was to identify the effects of current husbandry and management practices on the reproduction, behaviour and welfare of zoo-housed mouse deer. Questionnaires on husbandry and management practices were sent to all institutions in the EEP and ESB for the lesser and Philippine mouse deer, respectively, and behavioural data were collected in 15 of these zoos. For the lesser mouse deer, results show a positive effect of vegetation cover on breeding success, foraging and moving behaviours. The provision of enrichment and presence of water ponds also positively affected these behaviours. The time that pairs spent in close proximity had a negative effect on breeding success, but animals in more vegetated enclosures spent less time in close proximity to each other. Results could be partially explained by the natural habitat of this usually solitary species being tropical forest, which provides local water sources and undergrowth for cover from predators. For the Philippine mouse deer there were differences in activity measures recorded between zoos, but the sample size was small with differences in training, enrichment and vegetation cover likely to have been important. In conclusion, since mouse deer inhabit overlapping male and female territories, the usual practice of housing breeding pairs together may be appropriate, but we suggest that they should be provided with opportunities to avoid each other in complex enclosures with ample vegetation cover to maximise their natural behavioural repertoire and breeding success.