Self-Medicative Behaviour in Chacma Baboons

Researcher: Paula Pebsworth

At a time when the human-baboon conflict is escalating it is imperative that we gain a better understanding of baboon needs. This study will determine the home and daily ranges, and the feeding ecology of a troop of chacma baboons (Papio ursinus) found on Wildcliff Nature Reserve in the Western Cape of South Africa.

Emphasis will be placed on self-medication in order to gain insight into how and what baboons need to maintain their health. This data has implications for the management of baboons, both captive and wild and for the field of primatology (study of primates in general).

Background
Wildcliff Nature Reserve is approximately 955 hectares of deep kloofs (narrow valleys or gorges between mountains) with afro-montane forest, rocky mountaintops and high meadows of fynbos and renosterveld. The reserve is home to two troops of chacma baboons, one comprising less than ten members and the other with approximately 100. The larger troop is easier to follow and behavioural observations, faecal, plant and soil samples are being collected from these individuals.

Self-Medicative Behaviour
There is mounting evidence to suggest that primates obtain medicinal benefits from plant ingestion and this belief is gaining acceptance among primatologists. It has been hypothesised that secondary compounds present in plants and other non-nutritive sources have properties that help animals fight pathogens and parasites, improve the reproductive fitness of an individual, and lessen the many diseases caused by parasites.

The resident troop of chacma baboons at Wildcliff engage in geophagy - the practice of eating earth or soil-like substances, to obtain essential nutrients. Geophagy, one of the oldest known forms of self-medicative behaviour, has been observed in 20% of all primate species, but to date is essentially undocumented in baboons. It is apparent that geophagy is an important aspect of this troop's repertoire, based on preliminary findings.

Objectives
1. Document baboon behaviour (spatial and feeding ecology)
2. Monitor clay sites used by the baboons
3. Analyse clay
4. Collect faecal samples to be analysed for presence and abundance of parasites
5. Analyse all nutritive and non-nutritive items consumed by the resident troop
6. Determine underlying motivation for clay consumption
7. Based on secondary compounds present in diet, determine items in diet that may be used to maintain health homeostasis

Methodology
Observation of Behaviour
The resident troop of baboons is being followed from November 2009 through to August 2010. Behavioural observations - both individuals as well as the troop as a whole - will take place using a 15-minute scan method. Weather, location, and type (foraging, locomotion and social) will be documented.

Home and Daily Range Analysis
An adult female baboon will be trapped, sedated and collared with a self-releasing collar. Fixes will be captured hourly from 5am to 7pm. The battery should last for over one year.

Plant Consumption
Foraging behaviour is being documented - noting location, all nutritive and non-nutritive items consumed, and samples collected whenever possible. The aim is to find ingestion of items rare to the diet and/or of little nutritional value as well as ingestion of plants that are more common to the diet, but are also used ethno-medicinally by humans and/or have demonstrated biological activity, suggesting a medicinal component.

Faecal Analysis
Faecal samples of known individuals are collected whenever possible. Otherwise, anonymous samples are collected. The goal is to collect 20 samples every two weeks. All samples will be analysed in the parasitology laboratory at Kyoto University's Primate Research Institute.

Soil Analysis
In order to gain insight as to why the baboons consume clay on and around Wildcliff Nature Reserve, soils will be analysed. Several representative samples have been taken from areas where soil consumption is known to occur. Additionally, samples of neighbouring soil not consumed will also be sampled. 

Results
The results of this study will be published in peer-reviewed journals. The information will also be presented at the International Primatological Society 2010 Congress, Kyoto, Japan.

These observations, documenting the relationship between health, plant and clay use by free-ranging baboons, are expected to provide valuable insight in areas such as conservation, wildlife management, captive care and the field of primatology in general.