Project highlights

  • Extensive observations on zoo-housed gorillas and orangutans to better understand the physical and mental challenges posed to them by their ex-situ habitats
  • Developing innovative enrichments for captive gorillas and orangutans and testing the efficacy of these at Twycross zoo and other partner zoos
  • 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 gorillas to support 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 Tool (EDT) 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 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 apply concepts from the EDT approach to improve the welfare of zoo-housed Orangutans and Gorillas. Both species are difficult to care for in captivity, because of their large size, advanced cognitive abilities, sensitivity to stress, and their complex natural social groupings. Our CASE Partner – Twycross Zoo, is in the process of developing a state of the art new orangutan enclosure and improved gorilla enclosure as part of their recently awarded £20m National Science and Conservation Centre. This studentship is thus a fantastic opportunity to guide development of novel ways to replicate natural habitats in captive enclosures to improve the quality of life and conservation value of captive gorilla and orangutans in zoos and in our partner sanctuaries In Africa and Asia.

Wild gorilla sitting in vegetation wild orangutan crossing a gap in the forest canopy

Figure 1: Wild gorilla sitting in vegetation and wild orangutan crossing a gap in the forest canopy.

CENTA Flagship

This is a CENTA Flagship Project

Case funding

This project is suitable for CASE funding


University of Birmingham


  • Organisms and Ecosystems


Project investigator

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


How to apply


  1. Literature review of the behavioural ecology of wild and captive gorillas and 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 great apes to fill the knowledge gaps most relevant to improving the quality of life for zoo and sanctuary gorillas/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 Twycross and other zoos (as appropriate) and refine accordingly.
  4. Create a series of recommendations for ex situ gorilla/orangutan enclosure design and husbandry and share them with our network of partners via the UK’s Great Ape Welfare group; the Pan African Sanctuary Alliance (PASA) 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). Gillespie will provide training and support skills development in applied issues related to the health and welfare of zoo orangutans.  All 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 broader research programme in which we are working with a number of organisations involved in conservation and rehabilitation of a variety of species. This includes zoos in the UK (e.g. Chester, and Drayton Manor Zoos) in addition to the CASE partner Twycross Zoo, as well as NGOs involved in ape conservation in range countries. Thus, the student will be embedded in an existing network of organisations, and will benefit from the extensive experience and network of staff at the CASE partner Twycross Zoo.

Further details

We expect candidates to have a Merit or Distinction at MSc level in a relevant subject. Experience of collecting behavioural data on primates would also be an advantage, particularly 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 helpfuSee the Enclosure Design Tool we have created to help zoos and sanctuaries encourage their chimps and orangutans to use wild-type behaviours:

Please contact us if you have further questions:

Prof. Susannah Thorpe

School of Biosciences

University of Birmingham

+44 (0)121 414 5040

[email protected]

If you wish to apply to the project, applications should include:

  • A CV with the names of at least two referees (preferably three and who can comment on your academic abilities)
  • Submit your application and complete the host institution application process via: and go to Apply Now in the PhD Bioscience (CENTA) section. Please quote CENTA23_B6 when completing the application form.

Applications to be received by the end of the day on Wednesday 11th January 2023. 

Additional information for international applicants

  • All international applicants must ensure they can fulfil the University of Birmingham’s international student entry requirements, which includes English language requirements.  For further information please visit
  • Please be aware that CENTA funding will only cover University fees at the level of support for Home-fee eligible students.  The University is only able to waive the difference on the international fee level for a maximum of two successful international applicants.

Possible timeline

Year 1

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

Year 2

Complete observational work, refine experimental phase and complete data collection.  Share 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 gorillas throughout the life course in captive settings and test the efficacy of these at Twycross and other UK zoos (where necessary). 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


The main risk to the project from any respiratory and contact infection pandemic is to the fieldwork component. Short-term disruptions because of lockdowns could be accommodated by flexibility in the timeline, and may provide unique opportunities to study the behaviour of animals in the absence of visitors. If all fieldwork is stopped, focus could shift to a quantitative meta-analysis of already published data on this topic.