Alcohol is ubiquitous. As with having children or watching The Bachelor, the question of whether we choose to imbibe or not is an unavoidable one. Well, that might be because humanity’s connection to the drink dates back to a time when, well, there were no humans. A new piece from the BBC combs through a variety of studies, exploring “a deep historical link between fruit-eating animals and alcohol intake” that helps explain why humans are so adept at digesting alcohol and enthusiastic about drinking it.
Drawing upon a 2000 study by Robert Dudley entitled “Drunken Monkey Hypothesis,” the article explores how our earliest ancestors encountering alcohol in fermenting fruit helped our modern bodies somehow not violently expel every sip of Mike’s Hard Lemonade. The key is the genetic mutation of the alcohol dehydrogenase enzyme ADH4, which, throughout the course of evolution, became “40 times better” at breaking down alcohol.
The mutation was effectively ubiquitous in our ancestors by 10 million years ago, which might be significant. This is around the time that those ancestors started adapting to a terrestrial lifestyle and probably first encountered high ethanol content in fruits rotting on the forest floor. This point in prehistory also coincided with a period of climate change that saw forests in Africa shrink while grasslands expanded. In the new environments, fresh fruit would have been harder to come by.
This hypothesis complicates the widely accepted narrative that humans first embraced the drink roughly 9,000 years ago, when disaffected dads first began brewing IPAs in their closets.
The article fortifies Dudley’s study by touching on a 2015 study that, throughout the course of 17 years, discovered that wild chimpanzees like to get wasted on fermenting tree sap, with some even showing signs of tipsiness. It also touches on the curious case of the aye-ayes, primates with the same ADH4 mutation as humans.
Samuel R. Gochman, a student at Dartmouth College in Hanover, New Hampshire, and his team offered aye-ayes a choice of liquid foods made of sugar water and varying concentrations of alcohol (0 to 5%). The two captive aye-ayes could differentiate between the different alcoholic foods. They preferred to drink from the containers with higher alcohol doses of 3 and 5% over those with 1% and zero alcohol.
When the containers holding higher alcohol contents had run out, the aye-ayes continued to compulsively dip and lick their fingers. “This suggests that they really like those concentrations,” says Gochman.
Well, that explains all the aye-ayes at Four Loko’s IRL tour.