<p>When scientists caught the aye-aye on video using its strangely thin, eight-centimeter-long middle finger to deeply pick its nose, it pointed towards a larger mystery: why exactly do some animals eat their own snot?</p>.<p>The footage resulted in research that names the aye-aye, a peculiar nocturnal lemur with big ears found only in Madagascar, as the 12th primate who picks their nose.</p>.<p>It joins an illustrious group that includes gorillas, chimpanzees, macaques -- and of course humans.</p>.<p>Anne-Claire Fabre, an assistant professor at the Switzerland's University of Bern and lead author of a study published in the journal Zoology this week, told<em> AFP</em> that the researchers stumbled on the discovery "by chance".</p>.<p>She said they were "surprised" by the behaviour of a female aye-aye named Kali, who was being filmed at the Duke Lemur Center in North Carolina in 2015.</p>.<p>In the video, "the aye-aye inserts the entire length of its extra-long, skinny and highly mobile middle finger into the nasal passages and then licks the nasal mucus collected", the peer-reviewed study said.</p>.<p>"This video brings the number of species known to pick their nose to twelve," it said, adding that they all have "fine manipulative skills".</p>.<p>The middle fingers of aye-ayes are not only long and thin, but also have a unique ball and socket joint they use to knock on wood to locate grubs.</p>.<p>After seeing the video, "the first thing I was wondered is where this finger is going", said Fabre, who is also an associate scientist at London's Natural History Museum.</p>.<p>So the researchers used a CT scan of an aye-aye's skull to reconstruct the finger's journey, finding it probably went down the throat.</p>.<p>"There is no other possibility. Otherwise, it would have gone into the brain and then they die," Fabre said.</p>.<p>The researchers compared the finger's probing to a very deep Covid test.</p>.<p>But finding out exactly why aye-ayes -- or other primates -- pick their noses proved a more difficult task.</p>.<p>The scientists reviewed the existing literature and found that "most of it was jokes", Fabre said.</p>.<p>They did find one study which suggested that nose-picking could spread bacteria in a harmful manner.</p>.<p>Another said that eating snot could stop bacteria from sticking to teeth, so it might be good for oral health.</p>.<p>So why is there so little research on nose-picking?</p>.<p>"I think it's just something that people didn't think about because it's considered to be gross," Fabre said. However she added that lots of research has been done about coprophagia -- animals eating their own excrement -- which could also be considered gross.</p>.<p>The aye-aye, the world's largest nocturnal primate, is highly endangered -- in part because it is seen as a bad omen in its native Madagascar, she said.</p>
<p>When scientists caught the aye-aye on video using its strangely thin, eight-centimeter-long middle finger to deeply pick its nose, it pointed towards a larger mystery: why exactly do some animals eat their own snot?</p>.<p>The footage resulted in research that names the aye-aye, a peculiar nocturnal lemur with big ears found only in Madagascar, as the 12th primate who picks their nose.</p>.<p>It joins an illustrious group that includes gorillas, chimpanzees, macaques -- and of course humans.</p>.<p>Anne-Claire Fabre, an assistant professor at the Switzerland's University of Bern and lead author of a study published in the journal Zoology this week, told<em> AFP</em> that the researchers stumbled on the discovery "by chance".</p>.<p>She said they were "surprised" by the behaviour of a female aye-aye named Kali, who was being filmed at the Duke Lemur Center in North Carolina in 2015.</p>.<p>In the video, "the aye-aye inserts the entire length of its extra-long, skinny and highly mobile middle finger into the nasal passages and then licks the nasal mucus collected", the peer-reviewed study said.</p>.<p>"This video brings the number of species known to pick their nose to twelve," it said, adding that they all have "fine manipulative skills".</p>.<p>The middle fingers of aye-ayes are not only long and thin, but also have a unique ball and socket joint they use to knock on wood to locate grubs.</p>.<p>After seeing the video, "the first thing I was wondered is where this finger is going", said Fabre, who is also an associate scientist at London's Natural History Museum.</p>.<p>So the researchers used a CT scan of an aye-aye's skull to reconstruct the finger's journey, finding it probably went down the throat.</p>.<p>"There is no other possibility. Otherwise, it would have gone into the brain and then they die," Fabre said.</p>.<p>The researchers compared the finger's probing to a very deep Covid test.</p>.<p>But finding out exactly why aye-ayes -- or other primates -- pick their noses proved a more difficult task.</p>.<p>The scientists reviewed the existing literature and found that "most of it was jokes", Fabre said.</p>.<p>They did find one study which suggested that nose-picking could spread bacteria in a harmful manner.</p>.<p>Another said that eating snot could stop bacteria from sticking to teeth, so it might be good for oral health.</p>.<p>So why is there so little research on nose-picking?</p>.<p>"I think it's just something that people didn't think about because it's considered to be gross," Fabre said. However she added that lots of research has been done about coprophagia -- animals eating their own excrement -- which could also be considered gross.</p>.<p>The aye-aye, the world's largest nocturnal primate, is highly endangered -- in part because it is seen as a bad omen in its native Madagascar, she said.</p>