Tag Archives: slow loris

Study suggests that primates prefer alcohol in their nectar

Image credit David Haring

Image credit David Haring

From the pubs and bars that line the city streets to the fermented nectars, spas and fruits in nature, alcohol is everywhere. Much like humans, primates have adapted alcohol into their diets and – also like humans – evolved the ability to digest it quickly. Now, a new study shows that the strange aye-aye, a prosimian primate that possesses a genetic mutation also seen in humans and African great apes that accelerates alcohol digestion, prefers alcohol beverages.

The aye-aye is a nocturnal lemur originating from Madagascar with an evolutionary lineage that spans back almost 70 million years. They are some of the strangest creatures on the planet, with unique bony fingers that they use to find grubs in dying tree trunks.

“Aye-ayes are essentially primate woodpeckers,” said Nathaniel Dominy, a professor of anthropology and biological sciences at Dartmouth. “So it is puzzling that they can digest alcohol so efficiently.”

During the wet season, however, the proportion of tree nectar in the aye-aye diet increases. If this nectar is fermented, than a boosted alcohol digestion would start to make more evolutionary sense.

The team tested alcohol preference in two aye-ayes using a nectar-simulation solution of sucrose, as well as the preference of one slow loris, which is the only primate currently known to consume fermented nectar in the wild.

The alcohol concentrations in the nectar-simulation solutions were low, ranging from none to five percent in order to reflect the levels typically found in nature. For each liquid treatment there were two controls of tap water, each placed in a circular array of small-recessed containers in a round resin outdoor table. Positioning was randomized and the experimenters were blind to the contents of the containers during behavioral data collection to eliminate any kind of observational bias.

Each of the two aye-ayes conducted the trial once a day for a total of 15 days and 30 trials between the two of them. Conversely, the slow loris participated in one trial per day over five days for a total of five trials.

The results revealed that the aye-ayes could not only discriminate between the tap water containers and those with alcohol, they adjusted their intake according to the varying alcohol concentrations in the liquid treatments. In addition, they preferred the treatments with the highest concentrations of alcohol and continued to search the high concentration containers long after they were empty.

Data from the slow loris trials was too limited for any statistical results, but discrimination and preference patterns were almost identical.

The results highlight the idea that fermented foods were an important part of our ancestors’ diets and suggest that the genetic mutation that increases alcohol digestion seen in humans, African great apes and aye-ayes is linked to the consumption of fermented fruits on the forest floor.

“This project has definitely fueled my interest in human evolution,” said Samuel Gochman, a student from Dartmouth University and lead author of the study. “Our results support the idea that fermented foods were important in the diets of our ancestors.”

Journal Reference: Alcohol discrimination and preferences in two species of nectar-feeding primate. 20 July 2016. 10.1098/rsos.160217

The newly identified species of slow loris, Nycticebus kayan. (c) Shamma Esoof

New slow loris species discovered in Borneo is already threatened

Biologists have identified a new species of small nocturnal primates, part of the slow loris family, in Borneo’s forests. Don’t be fooled by its cute grim though, this tiny critter packs a punch, as its bite is poisonous and can cause harm to humans. Nevertheless, barely as it was discovered, scientists issued a warning to environmental agencies that the new slow loris is threatened with extinction due to habitat loss and trapping.

The newly identified species of slow loris, Nycticebus kayan. (c) Shamma Esoof

The newly identified species of slow loris, Nycticebus kayan. (c) Shamma Esoof

The new species of slow loris, named Nycticebus kayan, like most elusive nocturnal critters, has gone unnoticed because of its lifestyle. Professor Anna Nekaris of Oxford Brookes University in the UK, and Rachel Munds from the University of Missouri in Columbia, US had to survey great patches of forests in Borneo and the Philippines in search for the slow loris.

In the paper published in the journal American Journal of Primatology, the researchers describe the facial traits of the N. kayan that add up to form a sort of mask. The research has revealed there are actually four species of slow loris in the Philippines and Borneo, each with their own, subtly different but distinct head markings. Recently alone, two other slow loris species were identified,  N. bancanus and N. borneanus, which were previously considered subspecies of N. menagensis.

The N. kayan is already is already threatened, unfortunately, at the hands of deforestation and poaching. It’s not its fur or other commodities that makes it attractive for poachers, but its cuteness, which makes it a prime candidate on the illegal pet-trade market in Asia. The N. kayan delivers a fierce blow, being one of the few mammals with a toxic bite, so captive animals often have their canine and incisor teeth pulled out. This puts them at great risk since they can’t chew food properly, ultimately causing death. The toxin is powerful enough to potentially cause fatal anaphylactic shock in people.

 “Unfortunately, in addition to habitat loss to deforestation, there is a booming black market demand for the animals. They are sold as pets, used as props for tourist photos or dismembered for use in traditional Asian medicines,” Munds said.

She added that technological advances had enabled the team to identify it as a separate species. “Historically many species went unrecognised as they were falsely lumped together as one species. While the number of recognised primate species has doubled in the past 25 years some nocturnal species remain hidden to science.”