Leaf-swallowing in Nigerian chimpanzees: evidence for assumed self-medication.
A field study in Gashaka, Nigeria, adds the fourth subspecies of chimpanzee, Pan troglodytes vellerosus, to the list of African ape populations in which leaf-swallowing occurs. Unchewed herbaceous leaves of Desmodium gangeticum (Leguminosae-Papilionoideae) were recovered in 4% of 299 faecal samples of wild chimpanzees and clumps of sharp-edged grass leaves in 2%. The ingestion is believed to serve self-medicatory purposes because the leaves had a rough surface or were sharp-edged (which could be related to parasite control through a self-induced increase of gut motility), were not chewed, were excreted whole (indicating that they were not ingested for nutritional purposes), leaf-swallowing was restricted to the rainy season (during which time parasite re-infections are more common), and parasitic worms (Oesophagostomum stephanostomum) were found together with the leaves.
Fowler
Andrew
A
Department of Anthropology, University College London, Gower Street, London, WC1E 6BT, UK. a.fowler@ucl.ac.uk
Koutsioni
Yianna
Y
Sommer
Volker
V
D000818:Animals; D005243:Feces / Q000469:parasitology; D005247:Feeding Behavior; D009549:Nigeria; D009815:Oesophagostomum / Q000302:isolation & purification; D002679:Pan troglodytes / Q000502:physiology*; D018515:Plant Leaves; D012651:Self Medication