When scientists videotaped the aye-aye using its oddly thin, three-inch-long middle finger to pick its nose deep, it pointed to a larger mystery: why exactly do some animals eat their own snot?
The footage led to research naming the Aye-Aye, a peculiar nocturnal, big-eared lemur found only in Madagascar, as the 12th nose-picking primate.
It joins an illustrious group that includes gorillas, chimpanzees, macaques and, of course, humans.
Anne-Claire Fabre, an assistant professor at Switzerland’s University of Bern and lead author of a study published this week in the journal Zoology, told AFP that the researchers stumbled upon the discovery “accidentally”.
She said they were “surprised” by the behavior of an aye-aye female named Kali filmed at the Duke Lemur Center in North Carolina in 2015.
In the video, the aye-aye “inserts the entire length of its extra-long, thin, and highly mobile middle finger into the nasal passages and then licks the collected nasal mucus,” according to the peer-reviewed study.
“This video brings the number of species known to pick their noses to 12,” it said, adding that they all have “fine manipulative abilities.”
In addition to being long and thin, aye-aye’s middle fingers have a unique ball and socket joint that they use to tap on wood to find larvae.
After seeing the video, “the first thing I was wondering was where does this finger go,” said Fabre, who is also an associate scientist at London’s Natural History Museum.
So the researchers used a CT scan of an aye-aye’s skull to reconstruct the finger’s journey and found that it likely went down the neck.
“There is no other way. Otherwise it would have gone into the brain and then they would have died,” said Fabre.
Researchers compared probing the finger to a very deep Covid test.
– ‘Rough’ –
But figuring out exactly why aye-ays — or other primates — pick their noses proved to be a more difficult task.
The scientists reviewed the existing literature and found that “most of it was jokes,” Fabre said.
They found a study that suggested nose picking could spread bacteria in a harmful way.
Another said that eating snot might stop bacteria from sticking to teeth, so it might be good for oral health.
Why is there so little research on nose picking?
“I think it’s just something that people haven’t thought about because it’s considered gross,” Fabre said. However, she added that a lot of research has been done on coprophagia – animals eating their own excrement – which could also be considered disgusting.
The aye-aye, the world’s largest nocturnal primate, is critically endangered — in part because it’s considered a bad omen in its native Madagascar, she said.
