Picking your nose, a vast matter of primates

An aye-aye (Daubentonia Madagascariensis).

Iimagine the scene. As a biologist, you study the evolution of prehensile ability in primates in relation to their arboreal adaptation. Your object of attention at the moment: a lemur named aye-aye, particularly known for the impressive size of its fingers. You are not in Madagascar, the chosen land of the animal, but at Duke University, in North Carolina. Americans have become masters in the reproduction of these small primates. Suddenly, in front of your eyes, one of the guys stuffs his middle finger into one of his nostrils, ostensibly cures it… then eats the result of his labor.

“Hey, isn’t it just men who do that?” “, was surprised the biologist Anne-Claire Fabre

What to do ? Burst out laughing ? Turn your head, disgusted? Take your cell phone to post a video on Instagram? Anne-Claire Fabre, professor of biology at the University of Bern and curator in charge of mammals at the Swiss National Museum of Natural History, says she was surprised at first. “Hey, isn’t it just men who do that?” » Then, like a good scientist, she suspected a nice research topic. The result, co-authored by six researchers from five countries, was published on October 27 in the Journal of Zoology. “In the Halloween Number”, she says with a smile. Delicious article.

The researcher undertook to understand by what miracle the animal managed to push this long clawed middle finger into one of its nostrils, to perform back and forth movements there, all without blowing up its sinuses. Note that said appendix reaches 8 centimeters for a body of less than 40 centimeters (do the math and compare)… Renaud Boistel, from the Museum of Natural History in Paris, was responsible for reproducing the 3D anatomy of the creature and allowed to determine the improbable route. “The finger enters through the nose, threads its way to the pharynx and reaches the back of the mouthsummarizes Anne-Claire Fabre. In fact, the animal reproduces the movements it performs when it eats a raw egg or an orange: it scrubs, pulls out its finger and then licks it. We can also note that if the aye-aye also cleans his ears, he never eats what he extracts from them. »

“A lot of jokes”

But no good science without bibliographic study. So the team dove into the literature. “We realized that in addition to the ayes-ayes and us the practice of picking the nose had been described in ten other species of primates”, insists the Swiss researcher. Chimpanzees, bonobos, two species of gorillas, three species of macaques, Sumatran orangutans and two species of capuchins. Not to mention the less skilful species, such as giraffes, which for lack of fingers, lick the mucus that flows from their noses… The biologist notes, however, that few researchers go beyond anecdotal description. “It’s funny or it’s disgusting. Lots of jokes, little info”she summarizes.

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