Down With the Sickness: A Discussion of Primates Self-Medicating

Figure 1: Chimpanzee consuming a medicinal plant for the purposes of self-medicating

There is a lot that can be learned by observing nonhuman primates.  Primatologists, scholars who study nonhuman primates, undertake these studies not just to learn more about the specific species they are studying but also to gain a better understanding of what it means to be human.  Today's blog post will explore how the study of nonhuman primates can and does provide us greater insights into what it means to be human, as well as what we can learn that can help humans, specifically by looking at how nonhuman primates self-medicate.

The study of animal self-medication is known as zoopharmacognosy.  It is a uncommon area of biological studies, but one that has existed for several decades.  Through the study of zoopharmacognosy scholars have noted that a wide variety of animal species practice self-medication, or engage in acts to alleviate pain, expel parasites, or prevent infections.  The most notable of the animals to do this are nonhuman primates, specifically ape species.  Self-medicating behaviors are most often cited as occurring infrequently and as necessary.  Primates who engage in food consumption patterns that include products atypical to their usual diet and/or have no nutritional value are identified as participating in self-medicating rituals, particularly if those rituals occur when parasitic infections are more common.  It is even more certain that the practice is self-medicating if only one or a few nonhuman primates of the group are participating in the act.  These behaviors are most common among various ape species, specifically bonobos, chimpanzees, and gorillas.  Orangutans, another ape species, do not participate in self-medicating behaviors as outlined above.  Instead, they incorporate various medicinal plants as part of their regular diets, and they consume more of these plants when they are ill.

Self-medicating behaviors were noted as early as the 1960s and have been observed occurring over the next several decades.  The first behaviors were noted among chimpanzees who would consume whole leaves of nausea inducing plants, a behavior noted as odd since the action led to the consumption of a plant with no nutritional benefits.  It was later realized that the chimpanzees were participating in these actions to rid themselves of parasitic infections.  Similar actions have been noted among various other ape species, including the consumption of plants known among humans as laxatives. 

Non human primates do not just consume plants to cure internal maladies; they also use medicinal plants to aid in external issues, too.  They rub plants onto their skin and/or fur to rid themselves of external parasites or alleviate pain from sores, cuts, and bruises.  These behaviors have also been widely observed among various species over recent decades.

So what's all the fuss about nonhuman primates self-medicating?  This is an important feature of nonhuman primate intelligence because it is believed that such activities are learned behaviors that are passed down through the generations.  These also provide insights into what early human (hominid) ancestors did to survive in the face of various illness and other conditions.  Furthermore, scholars believe that by observing which plants are being used for medicinal purposes by animals humans can gain more knowledge about the potential medicinal benefits of said plants.  Ultimately, this demonstrates that primatological studies provide greater insights into the human condition than what many people may initial be led to believe.

References

Huffman, M. A. (2016). Primate Self-Medication, Passive Prevention and Active Treatment - A Brief Review. International Journal of Multidisciplinary Studies, 1-10.

Morrogh-Bernard, H.C., Foitová, I., Yeen, Z. et al. Self-medication by orang-utans (Pongo pygmaeus) using bioactive properties of Dracaena cantleyi . Sci Rep 7, 16653 (2017). https://doi.org/10.1038/s41598-017-16621-w

Shurkin, J. (2014). News Feature: Animals that self-medicate. PNAS, 17339–17341.

 

 

·