Current evidence for self-medication in primates: A multidisciplinary perspective

Abstract

The study of self-medication in non-human primates sheds new light on the complex interactions of animal, plant and parasite. A variety of non-nutritional plant secondary compounds and nutrient-poor bark is found in the primate diet, but little is yet known about the possible medicinal consequences of their ingestion. Recent studies of the African great apes support a hypothesis in progress that the non-nutritional ingestion of certain plant species aid in the control of parasite infection and provide relief from related gastrointestinal upsets. Detailed behavioral, pharmacological and parasitological investigations of two such behaviors, bitter pith chewing and leaf swallowing, have been conducted on three East African chimpanzee populations, but they are now known to occur widely among all chimpanzee subspecies, as well as bonobos and lowland gorillas. For both bitter pith chewing and leaf swallowing, selection of the same plant species tends to occur among neighboring groups of same ape species. These local cultural traditions of plant selection may be transmitted when females of the same species transfer into non-natal groups. However, selection of the same plant species or species of related plant genera by two sympatric ape species or between regional populations of great ape subspecies strongly suggests a common criteria of medicinal plant selection. This and the intriguing observa- tion that the same medicinal plant is selected by apes and humans with similar illnesses provide insight into the evolution of medicinal behavior in modern humans and the possible nature of self-medication in early hominids. The occurrence of these and other specific self-medicative behaviors, such as fur rubbing and geophagy, in primates and other animal taxa suggest the existence of an underlying mechanism for the recognition and use of plants and soils with common medicinal or functional properties. Yrbk Phys Anthropol 40:171-200, 1997. r 1997 Wiley-Liss, Inc.