Going Above and Beyond? An Analysis of Ape Behaviour and Space Use in an Innovative Captive Setting

Abstract

Contemporary animal husbandry encompasses a multi-disciplinary approach to animal welfare that draws upon the fields of animal science, psychology, and ethology. Environmental enrichment strategies, key elements of captive animal management in accredited zoological gardens, aim to enhance the physical and psychological well-being of individuals, as well as provide opportunities for the expression of species-typical behaviours. This thesis assesses the behaviour and space use of three orangutans - two Bornean (Pongo pygmeaus) and one Sumatran/Bornean hybrid (Pongo pygmeaus x abelii) - and two siamang gibbons (Symphalangus syndactylus) within brand-new enclosures at the Auckland Zoo. Both species are primarily arboreal and frugivorous in the wild but have been known to exhibit behavioural and dietary flexibility when faced with environmental changes. Establishing a behavioural baseline for Auckland Zoo’s captive apes, in light of the innovative nature of the new enclosures, will assist in future assessments of orangutan and siamang well-being in captive environments. The data were collected from December 2020 – February 2021 at Auckland Zoo’s Southeast Asia Jungle Track. A mixed use of focal animal follows and scan sampling recorded individual and social behaviours, as well as general patterns of space use, within both the orangutan and siamang habitats. The calculated activity budgets for the focal species, when compared to those of wild conspecifics, included increased time resting and decreased time spent eating and travelling, consistent with expectations for apes in highly managed, captive settings. Although the orangutans engaged with the innovative and complex overhead structures featured in the new enclosure design, the observed patterns of space-use among the orangutans reflects preferences for lower portions of the habitat and/or a sensitivity to human aspects of the managed setting. Space use profiles for the two siamang were highly aligned, as expected for pair-bonded individuals. The analysis of vertical space use for the siamang indicates that approximately one-third of their time is spent on the ground, which contrasts with wild populations. In sum, the highly managed nature of contemporary zoo settings, regardless of enrichment innovations, still presents challenges for the promotion of species-typical behaviour in captive apes.