Previous research showed chimpanzees feeding on fermented nectars, the animal world's source of alcohol. But it was never clear whether they are drinking it because of its high calorie content or if they are really born to like and seek booze.

Now, a new research suggests that primates and alcohol have a natural relationship and that they actually prefer feeding on nectar with higher alcohol content.

The study was done by researchers of Darthmouth College using two species of nectar-feeding primates--an aye-aye and a slow loris.

Aye-ayes, according to National Geographic, are lemurs that are only found in Madagascar. They are closely related to chimpanzees, apes and humans. Classified as omnivores, they usually feed on fruits, fungi and insect larvae.

Meanwhile, a slow loris is the only primate known to consume fermented nectar in the wild.

During the experiment, the two aye-ayes, named Morticia and Merlin, and one slow loris, named Dharma, were given five cups of sucrose (same with nectar) with different alcohol concentration (0 and 0.5 percent). A cup with tap water was also given to them. For 15 consecutive days, the aye-ayes were given the cup set once a day, while the slow loris was only tested five times.

Results revealed that both will pick alcoholic drinks over non-alcoholic ones. Further statistical analysis showed that they both prefer the nectar with the highest concentrations of alcohol. Upon studying the behavior, the researchers noted that the aye-ayes continued to probe the containers with the highest concentrations long after they were emptied.

"Aye-ayes used their fingers to compulsively probe the cups long after the contents were emptied, suggesting that they were extremely eager to collect all residual traces," said study author Nathaniel Dominy in a statement.

These species, just like humans, have genetic mutation that enables alcohol to be digested efficiently. It is considered an evolutionary advantage because it makes for an additional source of calories.

The new study provides more information about human evolution and supports the idea that alcohol is an important part of our ancestor's diet--and maybe provides an explanation why humans today like booze, too.