Wild chimpanzees regularly consume alcohol, new study says

Researchers collected 20 urine samples from 19 western chimpanzees, known scientifically as Pan troglodytes, in Kibale National Park. Seventeen of the samples contained clear signs of alcohol byproducts, confirming that the animals had recently consumed ethanol, the type of alcohol found in drinks.

Graduate student Aleksey Maro spent 11 days last August tracking chimpanzees in the Ngogo area of the park. Because breath testing was not possible in the forest, he collected urine samples from leaves, branches and the forest floor while the chimps fed in fruit trees.

Earlier research by Maro and his adviser, Professor Robert Dudley, showed that wild fruits eaten by chimps can contain enough alcohol from natural fermentation to equal about two standard drinks per day for a human. The new urine tests provide direct proof that the animals are absorbing that alcohol.

Of the 20 samples, 17 tested positive using strips designed to detect alcohol byproducts. Eleven samples were checked using a higher detection level, and 10 of those were positive. In humans, similar readings are usually seen within 24 hours after light drinking.

Dudley said the levels found were significant and consistent with the team’s earlier estimates of how much fermented fruit chimpanzees eat.

During the study, the chimps were feeding heavily on African star apples during a bumper fruiting season. Tests of fallen fruit showed relatively low alcohol content. However, the researchers believe the animals may have eaten riper fruit higher in the trees, which could contain more alcohol. Chimpanzees are estimated to eat about 4.5 kilograms of fruit per day.

Both male and female chimps tested positive, though negative results were more common among young animals and females in estrus. One possible explanation, Dudley suggested, is that males may compete for fruit with higher alcohol levels.

The team says more research is needed to understand how regular alcohol intake affects chimp behavior and health, including whether it influences aggression or reproduction.

The study also opens the door to testing other fruit eating animals. Dudley said similar test strips could be used in the wild to examine species such as fruit bats and others that rely on fermented fruit.

Earlier, Qazinform News Agency reported that your wine choice may say more about you than you think.