Primal Spirits: New Research Explores the Evolutionary Roots of Alcohol Consumption in Great Apes

Out of 20 urine samples belonging to 19 chimpanzees, 17 samples tested positive in tests sensitive to 300 ng/mL or more of ethanol. Among the 11 samples tested with a sensitivity threshold of 500 ng/mL, 10 were positive. For humans, a level of 500 ng/mL is typically observed after consuming one to two standard drinks in the past 24 hours; a level comparable to the morning consumption of slightly fermented fruits in chimpanzees. Robert Dudley remarked: "These levels are high and, even by conservative estimates, exceed some clinical and legal thresholds associated with humans."