Maintaining their health is vital to animals’ survival. To date, only a few studies have evaluated the role of geophagy, the deliberate and regular consumption of soil and other earth materials, in the protection of humans and other animals from plant toxins. This knowledge is critical to ensuring that animals have the resources they require to maintain their health.
Additionally, we must evaluate what benefits soil provides humans and animals and ensure that geophagy sites are protected and conserved. Finally, as animals are frequently translocated or bred in captivity, we must determine whether captive animals, which have lost the ability to naturally self-medicate, would benefit from soil supplementation.
Researcher: Paula PebsworthRegion: South Africa
Organization: University of Texas, San Antonio (USA) & Stellenbosch University (SA)
Doctorate of Science (DSc) – Kyoto University
– Pebsworth PA, & Huffman, MA. (under review). Geophagy in Non-human primates: health & evolutionary implications. Animal Behaviour.
– Pebsworth PA, & LaFleur, M. (under review). The camera never lies: camera trap use in primate studies. International Journal of Primatology.
– Pebsworth PA, Seim GL, Huffman MA, Young SL. (2013). Geophagic earth consumed by chacma baboons is low in bioavailable iron. Journal of Chemical Ecology 39:447-¬449
– Pebsworth PA, Archer CA, Appleton CC, Huffman MA. (2012). Parasite transmission risk from geophagic and foraging behavior in chacma baboons. American Journal of Primatology 74:940–947
– Pebsworth PA, MacIntosh AJJ, Morgan HR, Huffman MA. (2012). Factors influencing the ranging behavior of chacma baboons (Papio hamadryas ursinus) in a human-¬modified habitat. International Journal of Primatology 33:872-¬887
– Pebsworth PA, Morgan HR, Huffman MA. (2012). Evaluating home range techniques: use of global positioning system (GPS) collar data from chacma baboons. Primates 53:345-¬355
– Pebsworth PA, Bardi M, Huffman MA. (2012). Geophagy in chacma baboons: patterns of soil consumption by age class, sex, and reproductive state. American Journal of Primatology 74:48-¬57
BackgroundThe aim of this study is to determine whether animals self-medicate to avoid toxins. Geophagy, the deliberate and regular consumption of soil and other earth materials, is practiced world-wide by humans and other animals. Despite its small overall contribution to diet, there is strong evidence that soil ingestion positively influences health.
There are two main hypotheses to explain geophagy’s function: mineral supplementation and protection from plant toxins, parasites, and pathogens. Unfortunately, our knowledge of the soil’s capacity to detoxify plant toxins is limited. Therefore, the focus of this study is whether soil consumed by the Wildcliff troop of baboons in the Western Cape, South Africa, can detoxify plant toxins present in their diet.
The motivation to consume soil is so strong that animals risk predation and expand their home range to include geophagy sites. Several authors have concluded that the benefits of geophagy must be considerable, but most cannot state what those benefits are. At a time when human-animal conflict is high, it seems imperative that we gain a better understanding of what resources animals need to survive. We predict that if soils are consumed for protection against plant toxins, then baboons consume soil that will bind up plant secondary metabolites. This self-medicative behaviour would not only reduce exposure to plant toxins, but also allow exploitation of marginal dietary resources.
- To determine whether soils consumed by baboons can absorb or otherwise neutralise plant toxins that they naturally encounter.
- Create an in vitro testing protocol that simulates intestinal biochemistry and liver metabolism.
MethodologyThe Wildcliff baboon troop consumes over 85 different dietary items. Among those plants they eat are many which are known to contain toxins. To gain an understanding of phytochemical ingestions and primates’ possible detoxification strategies, we will test several plant species know to be especially toxic.
Using fresh plant material extracts will be created in the field. Plant toxicity, as well as the soil’s ability to reduce toxicity on dried extras and four representative plant toxins through in vitro simulation of digestion, will be assessed. Six types of extract will be created and then exposed to Artemia salina (brine shrimp nauplii). After 24 hours, the live and dead shrimp will be counted to determine the toxicity of the plant extracts.
The equipment needed to analyse these samples is very costly, however the University of Ottawa and Cornell University have generously donated use of lab space and equipment.