Past Projects

Apes are very intelligent and hence it is important that their environment in captivity affords them adequate physical and mental stimulation. One way in which this can be aided is to house two compatible species within the same enclosure. However, to date very few of these exhibits have been studied and very little is known about what factors may contribute to successful species-combinations.

Adelaide Zoo is only the second zoo in the world to successfully combine orang-utans and siamangs and during June/July 2007 a study was conducted to examine the behaviour of a male/female pair of orangutans and siamangs within a mixed-species exhibit. The purpose of this study was to record the behaviour of individuals within this environment and to examine the frequency and nature of any interactions that took place between species. It was found that the two species did show interaction which enriched the environment for the animals involved and provided an unrivalled viewing experience for zoo-visitors.

180 hours of observation took place over a 30-day period utilising instantaneous scan sampling techniques. During this period over 400 mixed-species interaction sequences were recorded. This interspecies interaction contributed to over 6% of the orangutan female’s daily activity and approximately 5% of daily activity for the siamang pair, indicating it increased stimulation and overall activity which is important for wellbeing in captivity. These three individuals often engaged in play-like interactions, previously unseen between these species. Such interactions included pulling of hair, play-fighting, wrestling, play-biting, chasing, rolling together on the ground, and poking or tapping each other. They also were observed grooming one another and sharing food.

The influence of the mixed-species exhibit appeared more neutral for the male orangutan. However, no instances of aggression were observed and individuals moved freely around the exhibit without segregation by species. Other significant findings of the research were the high level of time spent on the ground and the low level of foraging and climbing behaviour for all individuals.

Based on these findings, factors that may relate to successful mixed-species exhibits include the temperament and non-predatory nature of the species to be combined, the individual personalities of animals selected, adequate space in the exhibit, the presence of segregated areas, and the provision of the main feed in their separate night areas to avoid food competition.

From this study, suggestions were also provided on ways to encourage more natural behaviours, such as the use of scatter feeds to increase foraging, and the provision of food and structures in arboreal locations to promote climbing behaviour.