Project highlights

  • Extensive observations of zoo- (UK) and sanctuary- (Indonesia) housed orangutans to better understand the physical and mental challenges posed to them by their ex-situ habitats 
  • Developing innovative enrichments for captive orangutans and testing the efficacy of these at UK zoos and at orangutan sanctuaries in SE Asia  
  • Working with zoo and sanctuary partners with wide ranging expertise to create design and husbandry ideas to enhance the welfare and quality of life for ex situ orangutans to support global conservation and reintroduction programmes 


Unless human behaviour changes, many primates are at risk of extinction, including all great apes. Great apes that have been confiscated from the pet trade and are now living in sanctuaries across Africa and SE Asia, and those in zoos across the world, are central to the survival of the species. The ability of sanctuaries to reintroduce great apes into the wild, and of zoos to preserve the species, relies on encouraging them to exhibit the behaviours they need to survive in natural habitats. A key issue is how to replicate the complexity of forest, and the physical and mental challenges it poses for wild great apes on a daily basis, in the relatively simple and unchanging enclosures that are typical of captive settings.  

The Enclosure Design & Husbandry Tool (EDHT) is an interactive web-based application that translates research on wild apes into a format that captive settings can use to encourage wild-type behaviours in their apes. It compares behavioural-ecology data from captive individuals to data for wild individuals and recommends enclosure and husbandry modifications to elicit missing or under-represented wild-type behaviours. It focusses on replicating the mechanical challenges apes experience in the wild to create enclosures that behave naturally, rather than ones that look natural to visitors.  

This studentship will focus on orangutans because they are difficult to care for in captivity (due to their large size, advanced cognitive abilities and their complex natural habitat), and because they are part of an active programme of rehabilitation and release back into the wild by sanctuaries in Indonesia and Malaysia. The student will apply the EDT to key aspects of welfare and rehabilitation at UK zoos and our partner sanctuaries in Indonesia. This studentship is thus a fantastic opportunity to make a lasting difference to the quality of life and conservation value of captive orangutans in zoos and in our partner sanctuaries in Asia. 

A photograph of a wild orangutan crossing a gap in the tree canopy.

Figure 1: Wild orangutan crossing a gap in the forest canopy.


University of Birmingham


  • Organisms and Ecosystems


Project investigator

Prof Susannah Thorpe, University of Birmingham ([email protected])


Dr Jackie Chappell, University of Birmingham ([email protected])

How to apply


  1. Literature review of the behavioural ecology of wild and captive orangutans. This will include locomotor ecology, environmental cognition, psychological resilience and social behaviour and learning. 
  2. Observational and experimental studies of the behaviour of zoo-housed orangutans at UK Zoos and at sanctuaries in Indonesia to fill the knowledge gaps most relevant to improving the quality of life for zoo and sanctuary orangutans. 
  3. Translate those findings to develop mechanisms to encourage natural behaviours in captivity by creating enclosures that mimic the mechanical behaviour of natural forest habitats for gorillas and facilitate natural social behaviour. Test these at UK zoos (as appropriate) and refine accordingly.  
  4. Create a series of recommendations for orangutan enclosure design and husbandry and share them with our network of partners via the UK’s Great Ape Welfare group and the Orangutan Veterinary Advisory Board (OVAG). 

Training and skills

Students will be awarded CENTA2 Training Credits (CTCs) for participation in CENTA2-provided and ‘free choice’ external training. One CTC equates to 1⁄2 day session and students must accrue 100 CTCs across the three years of their PhD.  

Training in specialist methodologies required for behavioural data collection will be provided by Thorpe and Chappell. Chappell will provide training in sampling and recording cognitive behaviour, while Thorpe will provide training recording movement and ecology. Chappell and external training will provide additional training in the specific programming and statistical techniques required for this project (e.g. R). Both supervisors will support skills development in delivering impact and engagement from the project with zoos, sanctuaries and the public. 

Partners and collaboration

This PhD studentship is part of a broad research programme in which we are working with a number of partners in conservation and rehabilitation of a variety of species across the world. This includes zoos in the UK (e.g. Chester, Twycross, Drayton Manor Zoos), as well as NGOs in ape conservation in range countries (e.g. SOCP, and BOSF). We also work with the Orangutan Veterinary Advisory Group, who are a representative body for orangutan sanctuaries. Thus, the student will be embedded in a dynamic network of organisations. 

Further details

Further details on how to contact the supervisor for this project and how to apply for this project can be found here: 

For any enquiries related to this project please contact Prof. Susannah Thorpe, [email protected], or  Dr Jackie Chappell, [email protected].

To apply to this project: 

  • You must include a CENTA studentship application form, downloadable from: CENTA Studentship Application Form 2024. 
  • You must include a CV with the names of at least two referees (preferably three) who can comment on your academic abilities. 
  • Please submit your application and complete the host institution application process via:   Please select the PhD Bioscience (CENTA) 2024/25 Apply Now button. The CENTA application form 2024 and CV can be uploaded to the Application Information section of the online form.  Please quote CENTA 2024-B43  when completing the application form. 

Applications must be submitted by 23:59 GMT on Wednesday 10th January 2024. 

Experience of collecting behavioural data on primates would also be an advantage, particularly on great apes. Field experience, either in the wild or in sanctuaries overseas is essential, but does not need to be on great apes. Some knowledge of biomechanics and/or cognitive research is beneficial but not essential. Some experience (through a formal qualification or self-taught) of programming is also helpful. 

See the Enclosure Design Tool we have created to help zoos and sanctuaries encourage their chimps and orangutans to use wild-type behaviours: 

Possible timeline

Year 1

Literature review of orangutan behavioural ecology and welfare in wild and captive settings to identify knowledge gaps. Undertake training in behavioural ecology data collection at UK zoos. Begin observational studies and design first ideas for relevant experimental phase (to test the efficacy of different enclosure/husbandry modifications).

Year 2

Focus on observational work at zoos and an Indonesia sanctuary, refine experimental phase and complete data collectionShare ideas with stakeholder network and seek feedback to refine ideas.

Year 3

Complete analysis of all data. Translate into mechanisms to replicate natural behaviours in orangutans throughout the life course in captive settings and test the efficacy of these at UK zoos. Refine accordingly. Write and publish resulting papers.

Further reading

Chappell, J., Thorpe, S.K.S., (2022). The role of great ape behavioral ecology in One Health: implications for captive welfare and re-habilitation success. American Journal of Primatology 84, e23328. 

Chappell, J., Phillips, A. C., van Noordwijk, M. A., Mitra Setia, T., & Thorpe, S. K. S. (2015). The Ontogeny of Gap Crossing Behaviour in Bornean Orangutans (Pongo pygmaeus wurmbii). PloS One, 10(7), e0130291–15. doi: 10.1371/journal.pone.0130291 

Tecwyn, E. C., Thorpe, S. K., & Chappell, J. (2013). A novel test of planning ability: Great apes can plan step-by-step but not in advance of action. Behav Processes, 100, 174–184. doi: 10.1016/j.beproc.2013.09.016 

Thorpe, S. K. S., & Crompton, R. H. (2005). Locomotor ecology of wild orang-utans (Pongo pygmaeus abelii) in the Gunung Leuser ecosystem, Sumatra, Indonesia: A multivariate analysis using log-linear modelling. American Journal of Physical Anthropology, 127, 58–78. 

van Casteren, A., Sellers, W. I., Thorpe, S. K. S., Coward, S., Crompton, R. H. & Ennos, A. R. (2012) Nest Building Orangutans Demonstrate Engineering Know-How to Produce Safe, Comfortable Beds. Proceedings of the National Academy of Sciences  109, 6873-6877