Tambako the Jaguar File photo of a chimpanzee - drinking water. Tambako the Jaguar

CHIMPANZEES IN WEST Africa get drunk during lengthy “drinking sessions” involving the fermented sap of palm trees, according to a new study published today.

The report in the journal Royal Society Open Science focused on primates living in Guinea, which use leaves to soak up the fermented sap of raffia palms.

The sap is normally processed by humans to make palm wine, and can can contain up to 6.9 percent alcohol, which is stronger than most beer.

This is the first time regular, independent inebriation has been studied among animals, apart from anecdotal observations in wild apes, says Kimberley Hockings of Oxford Brookes University, one of the report’s co-authors.

The habitual and voluntary consumption of ethanol has been documented until now, only in humans.

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Baboons in South Africa are known to steal fermenting grapes from vineyards, and monkeys sometimes sneak the odd cocktail from tourists in resorts.

But the chimps in Boussou are unique because their alcohol consumption isn’t the result of any human interaction, the report said.

Some of the chimps “consumed significant quantities of ethanol and displayed behavioural signs of inebriation,” the study found.

While researchers note that no detailed behavioural data was collected, “some drinkers rested directly after imbibing fermented sap.”

The behaviour is still quite rare, though, Hockings said, with researchers combining their data from observations dating back to 1995.

Researchers said they observed 51 “drinking events” by individual primates over that period of time.

One adult male in particular accounted for 14 of 15 events.

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