If we’re being honest with ourselves, we all find ourselves picking our noses sometimes. But when it comes to efficiency it turns out we have nothing on aye-ayes – the Madagascan primates have been observed using their 8cm-long middle fingers to clear their nasal passages and then eating the rewards. And their fingers can reach all the way back to their throats. Yum.
As well as humans, other primates such as gorillas, chimpanzees and macaques have previously been observed using their digits to clear their nasal passages. But now, researchers have observed Kali, an aye-aye who lives at the Duke Lemur Center in North Carolina, using her pipe-cleaner-like middle fingers to do so, too.
What’s more, CT scans of the lemur’s skull carried out by an international team of researchers show that their fingers go deep. Very deep.
“It's a surprise because aye-ayes are quite an iconic species, so you would think it would have been reported somewhere before now,” said co-researcher Roberto Portela Miguez, a senior curator at the National History Museum.
“We were in for an even bigger surprise when we used CT scanning to see how the nose picking works internally, and the scan was mind-blowing. We were shocked from the reconstruction that the aye-aye's finger could reach through its nose almost to the back of its throat.”
Aye-ayes are a species of lemur native to Madagascar. They have six fingers on each hand, including a super-long middle finger that helps them to scoop out grubs from hollows inside trees.
CT scans revealed that, when inserted, the finger is long enough to travel through the entire nasal passage, reaching all of the way down to the pharynx, which sits between the back of the mouth and the windpipe.
But don’t expect to see your cat picking their nose anytime soon. The tendency seems to be unique to dextrous primates.
“We found that the behaviour tended to be reported in species that have a high level of dexterity with their fingers,' said Roberto. “Non-primates may not possess this same dexterity to pick their nose, and so it may just be a phenomenon that occurs within us and our closely related species.”