Wild Chimps Ingesting the Equivalent of an Alcoholic Beverage Daily from Ripe Fruit, Study Finds
Wild chimpanzees were discovered to take in a quantity equal of one beer's worth of ethanol daily from consuming overripe produce, according to researchers.
Researchers believe this supports the idea that our species may have gotten a preference for fermented beverages from mutual primate predecessors who depended on fermented fruit – a source of sugars and ethanol – for sustenance.
"The human inclination to alcohol may have stemmed from these eating habits of our common ancestor with chimps," said a research scientist.
Apes, similar to numerous other creatures, have been observed feeding on fermented fruits found on the jungle ground, but the current study represents the pioneering study to clearly quantify how significant ethanol they might be consuming.
Investigation Techniques
Investigators assessed the level of drinkable alcohol in fruits such as certain fruits consumed in large quantities by primates in parts of the continent.
Using the volume of fruits they normally eat, the chimpanzees were ingesting around 14g of alcohol – comparable with nearly two alcohol measures, or about one 330ml bottle of lager.
The fruits most frequently consumed were the types highest in ethanol levels.
The 'Drunken Monkey' Theory
This study adds weight to the so-called "tipsy primate" theory – the notion that the human appetite for alcohol was passed down from evolutionary forebears.
The concept was first proposed years ago by a professor who acts as a team member on the project.
Scientists were initially sceptical. But further evidence of "foraging monkeys" have been recorded in the past few years, as mentioned by a primatologist not involved with the research team.
"What we're realising from this work is that the connection with alcohol dates way back into our evolutionary past, likely approximately 30 million years," she said.
"Perhaps for chimpanzees, this is a great way to build relationships, to spend time on the forest floor, eating overripe produce."
Notable Limitations
It was important to note that the chimpanzees in the research were not taking in a high enough dose to become drunk. Had they consumed that much, "it would certainly reduce their ability to survive," said a different scientist.
Chimpanzees are now threatened, and the biggest threats they encounter include the loss of their woodland environments to agriculture, logging and urban expansion.
The research is published in a academic periodical.
