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With its large eyes, bushy tail, and sensitive ears, the aye-aye can look like a cute, albeit quirky, creature. But now researchers have found that it has a less eye-catching feature: it uses its long middle finger to pinch its nose and eat mucus.
Yes, yes, they are primates, like humans, but they are nocturnal, endangered and are found only in Madagascar. A subject of superstition, they have a number of unusual features, including rodent-like teeth and a thin, elongated finger with a spherical joint.
Although the animal is known to use its phenomenal finger to tap on hollow wood to locate larvae and fish for them, the researchers revealed they have video footage of it being used for another, rather mundane, purpose: picking up the nose.
“While doing so, this animal inserts the full length of its extra long, thin, highly mobile middle finger into the nasal passages and then licks the collected nasal mucus,” the authors wrote in the Zoology Journal.
Dr Anne-Claire Fabre, assistant professor at the University of Bern and co-author of the research, said she recorded the behavior on video in 2015 while observing captive aye-ayes at the Duke lemur center.
“I was really surprised,” Fabre said, adding that the entire middle finger has disappeared into the creature’s nose. “It’s almost 8cm, it’s really long and I was wondering where this finger was going.”
To dig deeper, the researchers created a 3D model using CT scans of the aye-aye’s head and hand to figure out where the middle finger was going. The results suggested that the figure extended deep into the head.
“This finger is practically going down the throat,” Fabre said, adding that while nose picking hadn’t been observed in nature, that didn’t mean it didn’t occur.
The team said the aye-aye was in good company when it came to nose picking, revealing that the trait had been recorded in at least 11 other primate species including humans, capuchins, macaques, chimpanzees and orangutans, with some species that also used tools to do the job. The researchers said nose picking appeared to be more common in species with fine manipulative abilities.
It’s unclear why yes, or other species, have a penchant for nose picking, with researchers noting that it could just be an act of “self-cleaning.” But, they added, the fact that several species ate the mucus suggests there may be other explanations.
Among them, the team noted, were studies that suggested that the “texture, crunchiness and salinity” of matter could be tempting, that snot consumption can prevent bacteria from attaching to teeth, and that trait could increase. immune responses. However, there may be drawbacks, they said: Other research has suggested that nose picking spreads nasal bacteria.
Fabre added that nose picking has not been studied and more research is needed. “When you study this kind of behavior, you never know where it is going, and sometimes you can discover an application that we don’t expect,” she said.