When you belong to one of the oldest species on Earth, you are certainly entitled to a little drink every now and then. And apparently, that's exactly what a type of lemur known as an aye-aye likes to do. A lot. A new study out of Dartmouth College figured out that the little prosimian likes to gobble up food with the highest alcohol content – but not necessarily for the reasons you think.
The aye-aye is the world's largest nocturnal primate and belongs to the group known as prosimians, which also includes the slow loris and bush baby. It is only found on the island of Madagascar and has one long finger that it uses to tap on trees to get grubs scrambling around. It then listens for the insects moving beneath the bark and uses the same long finger to dig them out, making it something of a mammalian woodpecker.
Unlike other prosimians though, the aye-aye has a genetic mutation in common with humans and great apes that allows it to metabolize alcohol 40 times faster than animals lacking the mutation, meaning that it can take in some hooch and not get too terribly drunk from it. Because alcohol is not only a way to make bad decisions on Tinder, but also a fairly decent source of calories (as any college freshman knows), the Dartmouth team wanted to find out if the aye-aye actually preferred more alcohol in its meals – which it can find in the wild in the form of fermented fruit.
So, in a study that seems like it was a lot of fun for both the lemur and the humans, they created a bit of booze by fermenting a nectar-simulating solution of sucrose. During a visit to the Duke University Lemur Center, they placed dishes containing the boozy brew on a table outside, and let two aye-ayes, named Morticia and Merlin go to town. They also invited a slow loris named Dharma to the party.
The concentration of alcohol in the dishes varied, but only got as high as five percent, to simulate the alcohol concentrations that might be found in fermented fruit in the wild.
The researchers found that they aye-ayes showed a clear preference for the dishes with the most alcohol and that they "continued to probe the containers with the highest concentrations long after they were emptied, suggesting that they wanted more," according to a Dartmouth report. Dharma too seemed to really prefer the high-hooch nectar, although the report says that the loris' behavior wasn't tracked enough to be statistically significant.
"None of the animals exhibited signs of impaired coordination or behavior, as intoxication was not part of the study," says Dartmouth. While that makes the study authors party poopers, it does point out that the animals are likely seeking out alcohol for its caloric — rather than buzz-inducing — properties. Then again, the critters were trying to get more out of the containers, so who knows how long the drinking session might have gone on.
The finding is a bit puzzling for the researchers because it's odd that the aye-aye developed a genetic mutation for rapid alcohol metabolism considering that its primary diet consists of grubs. One reason for this might be because the animals can devote up to 20 percent of their feeding time gulping down nectar from a "traveler's tree," a plant specific to Madagascar.
Being that the aye-aye shares the same genetic mutation with humans, the study authors feel that their work could shed light on the booze-consuming habits of our early ancestors.
"This project has definitely fueled my interest in human evolution" said Samuel Gochman, one of the study authors. "Our results support the idea that fermented foods were important in the diets of our ancestors."
The study has been published in the journal Royal Society Open Science.
In the following video, you can see the aye-aye wondering why the party ended so soon.