Hic! Chimpanzees in the wild get drunk on palm wine and have also developed various leafy tools to enable them to get high, scientists have discovered.
Researchers who observed wild chimpanzees living near the village of Bossou in the West African country of Guinea from 1995 to 2012 have confirmed, for the first time, that wild apes habitually drink alcohol.
Villagers in Bossou tap raffia palm trees for the sap, harvesting it with plastic containers placed near the crowns of the tall palms.
Villagers leave the containers alone for most of the day, collecting the palm sap in the early morning and late afternoon. The sweet palm sap ferments quickly into palm wine.
The researchers saw 51 instances in which 13 chimps used "leaf sponges" to drink fermenting sap.
Chimps would often fold or crumple leaves inside their mouths to produce a drinking tool. They dip these "leaf sponges" into their preferred drink, and then squeeze the leafy tools in their mouths.
"I was fascinated by this behaviour. To harvest the palm wine, chimpanzees at Bossou use a leafy tool as a spongy drinking vessel," study lead author Kimberley Hockings, a behavioural ecologist at Oxford Brookes University in England, told 'Live Science'.
The sap averaged about 3.1 to 6.9 per cent alcohol. For comparison, beer averages between 3 and 6 per cent alcohol, and wine can contain 7 to 14 per cent alcohol.
The chimps often drank the fermented sap in large quantities - equivalent to about three average-size beers.
Males accounted for 34 of the 51 instances of drinking - one adult male in particular accounted for 14 of the 51 instances.
A number of chimps appeared intoxicated, researchers said.
Hockings noted that these findings do not say for sure whether the chimpanzees were attracted to the alcohol.
Hockings suggested that a future experiment could be to give chimps access to both alcoholic and nonalcoholic palm sap, to see whether the apes are attracted to alcohol.
