How do you study and conserve gorillas without coming face to face with them?

De Vere, R. A., Warren, Y., Nicholas, A., Mackenzie, M. E., & Higham, J. P. (2011). Nest site ecology of the Cross River gorilla at the Kagwene Gorilla Sanctuary, Cameroon, with special reference to anthropogenic influence. American Journal of Primatology, 73(3), 253-261.

Research carried out in the Kagwene Gorilla Sanctuary in the Cameroon-Nigeria border region of West Africa aimed to establish whether the Cross River gorilla showed vegetation preferences when building nightly nests. The research also aimed to provide the first vegetation map of the newly defined sanctuary, and overlay gorilla nest locations to determine whether, and to what extent, anthropogenic activity affected their ranging.

The vegetation within the sanctuary boundary was mapped, and historic nest sites constructed between January 2006 and March 2008 were re-visited and assessed. Old nests persist in the environment for years after they are constructed, due to the altitude of the sanctuary and extreme dry season; some of these are re-used, but most individuals build a fresh nest each night.

The habitat map revealed significant anthropogenic impact, with only 57% being relatively undisturbed primary forest. The remaining 43% consisted of either grassland used by grazing animals and their herders, or farms beneath the tree canopy. When the location of all nest sites was overlaid onto the vegetation map, the clear avoidance by the gorillas of grasslands and farms, which visibly fragment the remaining forest in the sanctuary, became clear.

With regard to nesting behaviour itself, analysis of nest sites showed that ground nests are constructed preferentially in the dry season (when the forest floor is dry), and they are constructed on precipitous slopes, in light gaps and clearings, with an understory of mixed vegetation from which to construct the nest itself as well as to consume. Tree nests are predominantly built in the wet season, in primary forest.

Data gathering without direct observation

The research station was operated by the Wildlife Conservation Society and had been in operation since 2002. Their trackers were trained to find the previous nights’ nest, and follow the tracks of the two small gorilla groups (amounting to a total of approximately 15 individuals) without directly encountering them. The gorillas were not habituated in any way as it would be detrimental to their interests to be comfortable in the presence of humans.  Although local taboos protected them from being a source of bushmeat, poaching of other species was rife throughout the sanctuary and their prospects are improved if they avoid humans altogether.

The Cross River gorilla remains the most critically endangered sub-species of gorilla. With a population of only 300 individuals and ranging sites severely fragmented, conservation action plans require research and evidence as to the behaviour and anthropogenic impacts. This research aimed to contribute to that field of knowledge and was cited in the Revised Regional Action Plan for the Conservation of the Cross River Gorilla (Gorilla gorilla diehli) 2014–2019.

World Animal Protection’s view

World Animal Protection believes in an individual’s right to a good life and supports conservation efforts that gather vitally important data on the behaviour and threats to individuals and groups, without harming them or putting them at greater risk.