Just like humans, primates may be hardwired for happy hour in the jungle, a new study has revealed.
Nectars and fermented fruits are nature's organic cocktails, and it appears that some of our relatives actively indulge in them.
Indeed, researchers in New Hampshire have found that two species of primate enjoy drinking "booze" and they consume it like intoxicated drunkards — the stronger the content, the better.
A Taste Of Booze
Scientists from Dartmouth College put to test two species of monkey-like primates — the aye-aye and the slow loris species — and provided representatives a selection of beverages with different degrees of alcohol.
Researchers borrowed a slow loris named Dharma and two aye-ayes named Merlin and Morticia from the Duke Lemur Center in North Carolina to find out which were more naturally inclined towards heavily fermented forms of nectar that resemble booze.
Drink receptacles were placed in slots cut into a round table with lids that left a hole big enough for the animals to insert their fingers to taste the drinks.
This simulated the nectar-gathering process that these primate species perform in native habitats of aye-ayes and the slow loris: Madagascar and the Southeast Asian jungle, respectively.
The nectar substitutes contained 1 to 4 percent alcohol content, with tap water as a control.
In the end, researchers found that in all cases, even when they mixed the order in which the beverages were given, the primates preferred the nectar substitute with the strongest content.
In fact, Dharma the slow loris not only enjoyed booze, but had even had a "relative aversion" to tap water.
Morticia and Merlin, the aye-ayes, reportedly went directly for the drink with the highest alcohol content and continued searching the receptacles for more even after emptying them.
Nathaniel Dominy, a co-author of the study, says the primates perhaps relied on their sense of taste and smell to distinguish which drinks contained the higher alcohol levels.
And because the aye-ayes stuck their fingers into the receptacles over and over again, this suggests a "strong attraction," says Dominy.
Can It Pinpoint The Roots Of Alcoholism?
Although the level of eagerness was unexpected, researchers say the results of the study were not surprising because nectar or fruit is the primary source of food of primates.
But the findings have left scientists intrigued, especially those who study the origins of alcoholism.
Experts say gorillas, chimps and humans carry a gene that helps us take in decent amounts of alcohol without getting too intoxicated.
Matthew Carrigan, an expert from Santa Fe College who was not involved in the study, found that this certain gene had evolved from an ancestral ape about 10 million years ago long before humankind learned how to make alcohol.
Researchers propose that this metabolism trick dates to the period when some apes started hanging out on the ground and taking lots of fermented fruit under the trees.
George Perry, who has collaborated with Dominy but is also not involved in the new study, says aye-ayes carry the gene that helps process strong drinks efficiently. The species' preference for alcohol possibly corroborates with the idea that the gene helps animals adapt to drinking booze, he says.
The findings of the new study are published in the journal Royal Society Open Science.
Photo: Frank Vassen | Flickr
