Vervet monkeys (Chlorocebus pygerythrus)
Vervet monkeys are a small Afro-Eurasian primate of the family Cercopithecidae. They can be found abundantly across eastern and southern Africa and they occupy a range of habitats including shrubland, forest, savannah, and urban landscapes [1-2]. They form multi-male and multi-female, matrilineal troops that can consist of more than 70 individuals and exhibit a linear dominance hierarchy [3]. Vervet monkeys are classified as ‘Least Concern’ on the IUCN Red List because of their large population, thus are not a conservation priority. However, it is important to acknowledge and address the issues that commonly arise when monkeys and humans come into contact – the health, food and financial security of people, and the welfare of monkeys [4-5].
Current threats
The expanding human population and encroachment into wild areas increasingly puts humans and vervet
monkeys in contact. In urban environments, human-monkey conflict often arises as monkeys become
reliant on anthropogenic resources and thus, engage in conflict driving behaviours such as house and
garden raiding [6-8]. Similarly, in rural areas, monkeys exploit agricultural land by crop raiding. This behaviour enables monkeys to obtain an abundance of food with a high-energy content which requires less energy expenditure to locate, handle, and digest than wild foods [4,9-10]. Although this behaviour proves to be an efficient foraging strategy for monkeys, it threatens the livelihoods of subsistence farmers and farmers that rely on selling crops for their income [1].
Living in close proximity to humans can lead to vervet monkeys being killed or injured because of persecution by farmers and homeowners, including by poisoning, shooting, and trapping [11], hunting for bushmeat, electrocution, and vehicle collision [1,6,8]. Additionally, the capture of vervet monkeys for the exotic pet trade is a persisting problem despite the trade in non-human primates being illegal in a number of African countries [1,12]. The capture and transportation of live monkeys for the pet trade and the inadequate care given to pet monkeys, who have complex social, physical, and psychological needs, gives rise to poor standards of animal welfare [13].
Sanctuaries, such as the Wild Animal Trauma Centre and Haven and the Vervet Monkey Foundation, conduct important work to rehabilitate and release wild monkeys that have been injured or orphaned as a result of human activities, and ex-pet monkeys that have been handed in [1,12]. To reduce the number of monkeys requiring these sanctuaries, education and outreach programmes could be employed in target areas. Such programmes could address people’s ‘pest’ perception of monkeys, and people's lack of understanding of the implications for monkeys' welfare of keeping them as pets [1]. Furthermore, restoring and protecting the natural habitats of monkeys, which have been lost largely due to urban and rural expansion, could serve as an effective preventative measure for human-monkey conflict (see the work done by the Tanzania Forest Conservation Group and the World Land Trust) [8]. By conserving their natural habitat and enhancing natural food resource availability, and consequently reducing monkeys’ dependence on anthropogenic food resources, monkeys’ contact with humans could be reduced [8]. To find out more about some organisations that help to protect vervet monkeys, and to donate to their cause if you would like to do so, check out the charity links on the right.
Gallery (64 photos)
References
1. Healy, A. & Nijman, V. (2014). Pets and pests: vervet monkey intake at a specialist South African rehabilitation centre. Animal Welfare, 23, 353-360. https://doi.org/10.7120/09627286.23.3.353
2. Butynski, T. M. & de Jong, Y. A. (2019). Chlorocebus pygerythrus. The IUCN Red List of Threatened Species 2019: e.T136271A17957823. https://dx.doi.org/10.2305/IUCN.UK.2019- 3.RLTS.T136271A17957823.en Accessed on 06 March 2022.
3. Jarrett, J. D., Bonnell, T. R., Young, C., Barrett, L. & Henzi, S. P. (2018). Network integration and limits to social inheritance in vervet monkeys. Proceedings of the Royal Society B, 285. https://doi.org/10.1098/rspb.2017.2668
4. Fourie, N. H., Turner, T. R., Brown, J. L., Pampush, J. D., Lorenz, J. G. & Bernstein, R. M. (2015). Variation in vervet (Chlorocebus aethiops) hair cortisol concentrations reflects ecological disturbance by humans. Primates, 56, 365-373. https://doi.org/10.1007/s10329-015-0486-y
5. Alemayehu, N. & Tekalign, W. (2022). Prevalence of crop damage and crop-raiding animals in southern Ethiopia: the resolution of the conflict with the farmers. GeoJournal, 87, 845-859. https://doi.org/10.1007/s10708-020-10287-0
6. Chapman, C. A., Twinomugisha, D., Teichroeb, J. A., Valenta, K., Sengupta, R., Sarkar, D. & Rothman, J. M. (2016). How do primates survive among humans? Mechanisms employed by vervet monkeys at Lake Nabugabo, Uganda. In: Waller, M. (eds) Ethnoprimatology. Developments in Primatology: Progress and Prospects. Springer, Cham. https://doi.org/10.1007/978-3-319-30469-4_5
7. Patterson, L., Kalle, R. & Downs, C. T. (2018). Factors affecting presence of vervet monkey troops in a suburban matrix in KwaZulu-Natal, South Africa. Landscape and Urban Planning, 169, 220-228. https://doi.org/10.1016/j.landurbplan.2017.09.016
8. Patterson, L., Kalle, R. & Downs, C. T. (2019). Living in the suburbs: Space use by vervet monkeys (Chlorocebus pygerythrus) in an eco-estate, South Africa. African Journal of Ecology, 57, 539-551. https://doi.org/10.1111/aje.12629
9. Hill, C. M. (2017). Primate crop feeding behavior, crop protection, and conservation. International Journal of Primatology, 38, 385-400. https://doi.org/10.1007/s10764-017-9951-3
10. Cancelliere, E. C., Chapman, C. A., Twinomugisha, D. & Rothman, J. M. (2018). The nutritional value of feeding on crops: Diets of vervet monkeys in a humanized landscape. African Journal of Ecology, 56, 160-167. https://doi.org/10.1111/aje.12496
11. Guy, A. J., Stone, O. M. L. & Curnoe, D. (2011). The release of a troop of rehabilitated vervet monkeys (Chlorocebus aethiops) in KwaZulu-Natal, South Africa: Outcomes and assessment. Folia Primatologica, 82, 308-320. https://doi.org/10.1159/000337269
12. Guy, A. J. & Curnoe, D. (2013). Guidelines for the rehabilitation and release of vervet monkeys. Primate Conservation, 27, 55-63. https://doi.org/10.1896/052.027.0103
13. Soulsbury, C. D., Iossa, G., Kennell, S. & Harris, S. (2009). The welfare and suitability of primates kept as pets. Journal of Applied Animal Welfare Science, 12, 1-20. https://doi.org/10.1080/10888700802536483