According to new research, wild chimpanzees enjoy a drink or two in their down time and some appear to drink to excess if the opportunity presents itself.

Humans and chimpanzees split, genetically, between five and seven million years ago. That makes chimpanzee research especially valuable. It tells us about the animals themselves but it also appears to be shedding light on how far back some traits that we think of as human actually go.

We now know, for example, that chimpanzees have a basic understanding of fairness but are not above fighting over land. They understand language, use tools, have a sense of humor, mourn their dead and according to a study published in the journal Royal Society Open Science they like to drink.

Previous research has shown that African apes, like humans, have a genetic mutation that allows them to metabolize alcohol. However, until now, there has been no hard evidence that apes drink in their natural environment.

The new research suggests that they not only drink, but that they do so regularly and that they will drink to the point of passing out.

The researchers observed wild chimps in Bossou in the Republic of Guinea, West Africa using a leaf sponges to extract fermented sap from the raffia palm.

The tool was made by chewing and crushing leaves, making them sponge like. The chimpanzees would place the tool in the opening of the sap container and then place it in their mouths.

According to the researchers, the entire group participated in the activity regardless of age or social standing.

“Some individuals were estimated to have consumed about 85ml of alcohol (which is the equivalent to 8.5 UK units) and displayed behavioural signs of inebriation, including falling asleep shortly after drinking,” said Dr Kimberley Hockings in a statement.

Hockings, of Oxford Brookes University and the Centre for Research in Anthropology (CRIA-FCSH/UNL) in Portugal is the lead author of the new paper.

“Our research demonstrates that there is not a strict aversion to food containing ethanol in this chimpanzee community. This new use of elementary technology shows once again how clever and enterprising humankind’s nearest living relations are,” added Hockings.