Particle.news
Download on the App Store
19 ARTICLES
·
yesterday

Wild Chimps Consume Daily Alcohol From Fermenting Fruit, Study Finds

New measurements suggest ancestral exposure to fermented fruit helped shape primate attraction to ethanol.

Image
A chimpanzee eating figs at Ngogo in Uganda’s Kibale National Park in 2018. UC Berkeley biologists measured the ethanol content of many types of fruit that chimps routinely consume and found that they contain substantial quantities — enough to suggest that the apes are chronically exposed to dietary alcohol.
Image
A chimpanzee is seen in the trees of Kibale National Park in Uganda. 

Overview

  • UC Berkeley researchers measured ethanol in 21 fruit species at chimp sites in Ngogo, Uganda, and Taï, Ivory Coast, finding roughly 0.3% alcohol by weight.
  • Based on typical diets of about 10 pounds of fruit per day, chimps ingest around 14 grams of ethanol daily, equal to one U.S. standard drink and more than two when adjusted for body mass.
  • Scientists collected freshly fallen, undamaged fruits tied to observed feeding and used a portable gas chromatograph, breathalyzer-like tools, and chemical assays to quantify alcohol.
  • Despite chronic low-level exposure during all-day foraging, observers reported no obvious signs of intoxication in the animals.
  • Findings support the long-debated 'drunken monkey' hypothesis, with follow-up work underway to test urine for alcohol metabolites and to assess whether chimps prefer higher-ethanol fruits.