Zoology
Chimpanzees with wounds or infections eat plants with antibacterial or anti-inflammatory properties
SEVERAL plants eaten by chimpanzees when they are ill or wounded have been found to have medicinal effects, providing some of the strongest evidence yet that our close relatives practise self-medication.
Reports of chimpanzees self-medicating with plants have been around for decades, but it is difficult to establish when wild animals are ill and what effect their diet has.
Now, Elodie Freymann at the University of Oxford and her colleagues have followed wild chimps through Budongo Forest in Uganda, recording when they were ill and what they ate. The researchers identified chimps with obvious wounds or with gut infections by analysing their faeces for signs of intestinal worms, as well as checking urine samples for raised levels of immune cells.
Analysis of 53 extracts of plants consumed by the ill or injured chimps showed that 88 per cent were active against bacteria that are pathogenic in humans, including antibiotic-resistant strains like MRSA. Extracts from every sampled species had anti-inflammatory effects (PLoS One, doi.org/m4k7).
Sick chimps often left the safety of their group to find and eat specific plants, and picked out species only rarely eaten in the area. The infrequency of these events is what makes self-medication so hard to observe, but also provides one of the strongest pieces of evidence that it is a targeted response to illness.
Chimpanzees are usually reluctant to try unfamiliar
