Ecology and conservation of pangolin using stable isotope forensics


The giant ground pangolin (Smutsia gigantea – Illiger, 1815) of the African lowland rainforest and savanna gallery forests is one of the world’s least studied animals. It is the largest of the pangolin species, with a mass of around 33 kg, and in common with the other species is myrmecophagous, providing an important ecosystem service as a regulator of social insect populations. Our current knowledge of pangolins is hampered by their predominantly nocturnal lifestyle, the fact they use a complex system of deep inaccessible burrows, and further, their jeopardy by poaching and trafficking. We know little about their movements and population sizes, and our lack of knowledge about their ecology hinders our efforts to protect them. This PhD position will exploit technical advances in stable isotope analysis to provide long-sought data on the ecology and life history of giant pangolins.

Pangolins are the only mammals with overlapping keratinous scales covering the body as dermal armour. The steep rise in demand for harvested pangolin scales is driven by their use in traditional medicines in Asia and to some extent in Africa. Now that the IUCN lists all four Asian pangolin species as endangered or critically endangered, intensive poaching has increased in the four vulnerable and decreasing African species, with 46.8 tonnes of scales being confiscated in the first half of 2019. Given the large size and slow reproductive rate of S. gigantea, this species seems particularly susceptible to poaching pressure. The intensification of this threat to pangolins underlines the urgency for developing analytic approaches that can help antipoaching efforts as well as clarify pangolin ecology.

This PhD position aims to develop a groundbreaking method that would provide governments with rapid and accurate tools of habitat conservation, and improve wildlife crime forensic science in general. The research promises to facilitate the identification of the geographic origin of confiscated scales, along with greater knowledge of habitat resource preferences and life history traits for S. gigantea, all of which are essential for the conservation management of this species.

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Image Captions

Figure 1. Taking measurement on a female Giant Pangolin (Smutsia gigantea) captured in Wongua Wongue Presidential Reserve in Gabon; a coastal forest-savanna mosaic.
Figure 2. Triple worldwide firsts. First active tracking to capture of a chosen giant pangolin. First sedation and first GPS-tagging of this species. From left to right: Dr. Halbwax WCU Wildlife Veterinarian, Jamaeel Ebengue WCU team member, Wesley Mouele WCU team member, SG01 aka “Ghost”, Dr. Lehmann Director of Research and WCU Chief. With 38 kg for 1.72m. SG01 is the biggest giant pangolin ever recorded. He was captured in the continental forest-savanna mosaic of Lope National Park.


The project has two main objectives, both driven by stable isotope analysis (SIA): 1.) to address knowledge gaps in the ecology of S. gigantea, and 2.) to exploit the potential of using stable isotope methods to forensically identify the geographic origin of confiscated pangolin scales.
The student will work with ANPN’s Wildlife Capture Unit (WCU) to capture and GPS-tag pangolins from Gabonese parks. This team led by Dr. Lehmann is composed by very experienced ecoguards, master trackers, a field biologist and a wildlife veterinarian. Pangolins will be actively tracked in the field, leaving no trails behind, without disturbing their natural habitats. As all the field sites are in very remote locations, we do not envision any negative impacts on local communities. The Wildlife Capture Unit has developed species-specific safe and field-friendly anaesthetic protocols to sedate individual species, including giant pangolin. The immobilized individual is closely monitored during the entire duration of the operation. During capture, all individuals will be measured, weighed, sexed, and samples for SIA will be collected. In addition, to bolster stable isotope modelling, prey items and environmental (plant, water) samples will be collected from within individual’s home ranges.

After tagging, GPS spatial data can clarify life expectancy, territoriality and home-range size, daily path lengths, distance travelled, social interactions and reproductive behaviours. Furthermore, SIA of keratinous scales provides dietary and/or environmental information about the animal at the time of keratin deposition. Conventional methods of dietary analysis, e.g. the analysis of stomach contents, are at best invasive methods and offer only a “snapshot” of what an animal is eating at one time. SIA allows the quantification, via mixing-models, all of the dietary items that a pangolin eats, and at the same time, indicates how much time an animal spends in different habitats retrospectively (e.g. riparian vs. forest ecosystems). Thus, SIA offers a non-destructive method of dietary analysis. Further, high-resolution subsampling of scales may provide information on ontogenetic habitat or dietary changes in individual animals. The student will develop optimal sampling protocols, including microscopy and microsampling techniques to minimize sample mass and maximise temporal resolution along each scale.
Whilst SIA is useful for defining ecological parameters, SIA has also been used in other species and their products (e.g. elephant ivory) to identify location. It is often the case that confiscated pangolin material is in the form of large quantities of scales, which are difficult to identify to species, never mind location. Development of a method to identify the location of scale mixtures would allow targeted conservation measures.
A database of stable isotope compositions of pangolin from known locations (starting with Gabonese locations) will allow us to determine origin from confiscated scales of unknown origin. This is based on isotopic gradients associated with latitude (δ2H and δ18O) savannah-forest and humidity (δ13C and δ15N) coastal proximity (δ34S and δ2H) and bedrock geology (δ34S). Data provided by this project will support ANPN conservation action plans and environmental policies.

Project Timeline

Year 1

Initial stable isotopes and generic PhD training, plus fieldwork in Gabon, including pangolin capture and sample collection.

Year 2

Characterisation of scale morphology and growth; microsampling of scales at SUERC; Stable isotope measurement of samples and isoscape reconstruction, manuscript preparation.

Year 3

GPS and stable isotope data analysis & papers.

Year 3.5

Thesis, policy papers

& Skills

On-site training at SUERC in the measurement and use of stable isotopes for drawing inferences about animal diet, small-sample handling, fieldwork training in Gabon, habitat and geolocation, modelling, data management, modelling, data management, taxonomy (prey items). Our team of supervisors is well placed to provide the diverse kinds of training required, all supported by a dedicated team of lab and field technicians in Scotland and Gabon.

This work will be undertaken in partnership with ANPN, the government agency administrating national parks in Gabon, with whom the research team has a long record of collaboration for research on both tropical ecology and conservation management.

References & further reading

• Challender D. and Waterman, C. (2017) Implementation of CITES decisions 17.239 b) and 17.240 on pangolins (Manis spp.). Prepared by IUCN for the CITES Secretariat. SC69 Doc.57 Annex 1.
• Challender, Daniel WS, Helen C. Nash, and Carly Waterman. Pangolins: Science, Society and Conservation. Academic Press, 2019.
• Hobson K.A. and Wassenaar L.I. eds., (2018) Tracking animal migration with stable isotopes. Second Edition, Elsevier. ISBN 9780128147238
• Ingram D.J. et al. (2018) Assessing Africa-wide pangolin exploitation by scaling local data. Conservation Letters 11, e12389 (doi:10.1111/conl.12389)
• Kabalika, Z., Morrison, T.A., McGill, R.A., Munishi, L.K., Ekwem, D., Mahene, W.L., Lobora, A.L., Newton, J., Morales, J.M., Haydon, D.T. and Hopcraft, G.G., 2020. Tracking animal movements using biomarkers in tail hairs: a novel approach for animal geolocating from sulfur isoscapes. Movement Ecology, 8(1), pp.1-10.
• Lajtha K. and Michener R. (2007) Stable isotopes in ecology and environmental science. Second Edition, Wiley/Blackwell. 592 pp. ISBN 9781405126809
• Lehmann, D., Halbwax, M. L., Makaga, L., Whytock, R., Malata, L. L. N., Mouele, W. B., … & White, L. J. (2020). Pangolins and bats living together in underground burrows in Lopé National Park, Gabon. African Journal of Ecology.
• Mambeya M.M. et al. (2018) The emergence of a commercial trade in pangolins from Gabon. African Journal of Ecology 56, 601– 609. (doi:10.1111/aje.12507)
• Newton, J. (2016) Stable isotopes as tools in ecological research. In: eLS: Encylopedia of Life Sciences. Wiley, pp. 1-8. ISBN 9780470015902 (doi:10.1002/9780470015902.a0021231.pub2)
• Phillips et al. (2014) Best practices for use of stable isotope mixing models in food-web studies. Canadian Journal of Zoology 92, 823-835. (doi:10.1139/cjz-2014-0127)
• Rysava K. et al. (2016) Re-constructing nutritional history of Serengeti wildebeest from stable isotopes in tail hair: seasonal starvation patterns in an obligate grazer. Rapid Comm. Mass Spectrom. 30, 1461-1468. (doi:10.1002/rcm.7572)
• Wang et al. (2016) Pangolin armor: Overlapping, structure, and mechanical properties of the keratinous scales. Acta Biomaterialia 41, 60-74. (doi:10.1016/j.actbio.2016.05.028)
• Ziegler S. et al. (2016) Towards understanding isotope variability in elephant ivory to establish isotopic profiling and source-area determination. Biological Conservation 197, 154-163. (doi: 10.1016/j.biocon.2016.03.008)

Further Information

Application procedure: For IAPETUS2 applications to the University of Glasgow please use the dedicated application portal:  (you will still need to submit your administrative details to the IAPETUS2 website as well).

Policy Minister of Environment Gabon:

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