Observations on the illness and consumption of a possibly medicinal plantVernonia amygdalina (Del.), by a wild chimpanzee in the Mahale Mountains National Park,Tanzania

Detailed observations on the consumption ofVernonia amygdalina (Del.), a naturally occurring plant of known ethnomedicinal value, by an adult female chimpanzee (Pan troglodytes schweinfurthii) of M-group in the Mahale Mountains, Tanzania were made. Chewing the pith of several shoots, she sucked out and swallowed the astringent, bitter tasting juice; spitting out the fibrous remains. The female was followed during this period for 11 hr, over two consecutive days, and was recognized to be in irregular health at the time of consumption, exhibiting signs of lethargy, lack of appetite, and irregularity of bodily excretions. The low frequency and lack of seasonality in the usage of this plant suggest that it is sought after for reasons other than as a food source. These factors suggest that for chimpanzees, the consumption of this plant is primarily medicinal. The symptoms displayed by the female are the same as those experienced by people throughout tropical Africa who utilize this plant as a medicinal treatment for them. Interactions between the female and others suggest that they too were aware of her condition and coordinated their activities with the female and her infant.