Chimpanzees at a site in West Africa drink alcohol-containing sap from raffia trees — the first systematic evidence that non-human apes ingest naturally fermented food in the wild.

In Guinea, local people collect this sap by hanging containers under holes tapped near the crowns of raffia palms (Raphia hookeri). Kimberley Hockings at the Centre for Research in Anthropology in Lisbon and her colleagues found that the chimps dip crumpled leaves into the containers to sponge out the sweet sap, which contains about 3% ethanol.

The results suggest that the last common ancestor of African apes and humans could tolerate the consumption of ethanol.

R. Soc. Open Sci. 2, 150150 (2015)