Orangutan Behaviour and Adaptation to the Forest in a Rehabilitation and Release Setting

  • Florence Rocque

Student thesis: Doctoral Thesis


Rehabilitation and release are commonly used for confiscated, surrendered, and rescued primates. Where it is possible for rehabilitant primates to return to the wild, measures for rehabilitation and release should be optimised to promote the best outcome. To increase orangutan rehabilitation and release success, a better understanding of their behaviour post-release is required. It is important to generate accurate behavioural profiles of release candidates and to understand how individual differences may impact how animals adapt to wild ecological environments, specifically in terms of skills that are vital for independent forest life. The aim of this thesis is to provide insight into how measurable behaviours might influence adaptation to the forest in rehabilitant orangutans; and to underscore the benefits of an individualised approach towards rehabilitation management. I examined foraging behaviours and found that individuals differed in their in fruit eating. I found that a reduction in feeding on provisioned food and an increase in experience in the forest and ranging behaviour, was related to more time spent feeding on fruit. I then considered the importance of travelling in the forest and focused on individual differences in the maximum distance travelled away from the rehabilitation centre. My data suggests individual differences in rehabilitant travel distances may corresponded positively with their rates of nest building and of tree climbing. These results may help in future efforts to refine methods to promote skill acquisition in rehabilitant orangutans by indicating the behaviours most significant in predicting forest adaptation. Finally, I evaluated a rating approach to collect pre-release behavioural data on the orangutans and argue this has potential to be a valid method of rehabilitation assessment, which could be easily implemented across other rehabilitation programmes. Overall, the results from this project indicate that a systematic and individualised approach to rehabilitation management may benefit adaptation to the forest in rehabilitant orangutans.
Date of Award3 Oct 2022
Original languageEnglish
Awarding Institution
  • University of Portsmouth
SupervisorMarina Davila Ross (Supervisor), Kim A. Bard (Supervisor) & Jerome Micheletta (Supervisor)

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