Capuchin Remedies

Zoopharmacognosy, or self-medication, is the use of specific plants (or in some cases arthropods) by wild animals to combat parasitic infection or disease. Self-medication has been widely documented in the great apes. One particularly interesting example has been documented in chimpanzees (Pan troglodytes) and gorillas (Gorilla gorilla) and bonobos (Pan paniscus) ingesting and defecating whole leaves in order to purge intestinal parasites (Huffman et al. 1996; Huffman 1997; Huffman & Caton 2001). Rough leaves are folded between the tongue and pass through the gastrointestinal tract intact (Huffman & Caton 2001). These leaves not only scour the gut, forcing expulsion of parasites and eggs but also stimulate diarrhoea, expelling the worms and possibly toxins from the body (Jain et al. 2008). Not pleasant, but effective. White-bellied spider monkeys (Ateles belzebuth) and red howler monkeys (Alouatta seniculus) in Ecuador engage in geophagy – the eating of soil – which is believed to provide them with a variety of nutritional and health benefits (Link et al. 2011).

Chimpanzees eating rough leaves to get rid of parasites. Nigel Swales/wikimedia, CC BY-SA (http://theconversation.com/how-other-primates-self-medicate-and-what-they-could-teach-us-59869)

In capuchin monkeys, the most commonly reported method of self-medication is fur-rubbing or anointing. Anointing can be a solitary or social behaviour and involves a monkey rubbing a foreign substance (e.g. leaves, insects etc.) into it’s fur. In white-faced capuchins (Cebus capucinus) this behaviour is highly social and results in a writhing, drooling ball of very excited monkeys rubbing a variety of plants including Citrus fruits, Piper leaves, Sloanea terniflora fruit and insects (Lynch Alfaro et al. 2011). A review of the variation in anointing behaviours between Cebus and Sapajus species found that Cebus species – the nontufted capuchins – anoint at higher frequencies than Sapajus species – the tufted capuchins, but do not anoint with a higher diversity of materials. This review also found that Cebus uses more plants for anointing and Sapajus more commonly use insects. This behaviour is a type of self-medication as the plants and insects used contain , often very strong, secondary compounds with healing and insect-repelling properties (Jain et al. 2008).

Self-medication in wild primates is certainly a fascinating topic. In Laguna Blanca, I have only seen two incidences of fur rubbing by the hooded capuchins. Both occurred in rather strange circumstances. The first happened back in 2014 (and is described in a natural history note currently under review). During an observer directed threat display, a large adult male in F Group seized a handful of leaves from a Citrus tree and furiously rubbed them all over his fur and then threw them into the air. During the entire display he was loudly alarm calling and threatening me. The second occurred just this week. Two juvenile capuchins came within a few metres of the primate team before settling in the branches of the tree and chewing leaves before rubbing them into their fur. Two individuals engaged in this behaviour separately at first and then together – though the social rubbing only lasted for a couple of second. The unusual thing about both these sightings was that they occurred during observer directed displays.

Young capuchin during solitary fur rubbing bout (Photograph: Anna O'Riordan)

Another suspected case of self-medication is the bark eating behaviour that both groups of capuchins at Laguna Blanca engage in. They only eat the bark of a single tree species and, though little information is available on the exact species, the genus is well known to have various medicinal properties, including anti-parasitic properties!! Parasitological analysis planned for the future will help shed more light on this interesting behaviour!

Adult capuchin eating bark while a juvenile watches (Photograph: Carter Payne)