Aye-ayes, the scraggly, bug-eyed, spindly-fingered lemurs of Madagascar, have historically been demonised by humans for their unusual and unappealing anatomy. But the species is going to have to get an even better publicist, because one individual was recently caught on camera picking its nose and eating what came out.
The individual in question is Kali, a female aye-aye at the Duke Lemur Centre in North Carolina. Kali managed to get her entire third finger up her nose, and, per the video evidence, then slurped up the snot that she pulled out.
A study describing the nose picking (scientifically known as rhinotillexis) is published this week in the Journal of Zoology. The researchers also investigated the mucus-eating element (scientifically, mucophagy) shown in the video.
In Kali’s defence, aye-aye fingers were made for picking. The primate’s hand makes up 41% of its forelimb (imagine an average-sized human with a foot-long hand). Aye-ayes have six fingers on each hand; three are mostly normal, one is a pseudo-thumb, and the third and fourth fingers are extra-long, built for rapping on rotten wood and extracting grubs from within.
“When I first saw this video, I was really struck by the nose picking,” said Roberto Portela Miguez, the senior curator in charge of mammals at London’s Natural History Museum and a co-author of the research, in a museum release. “It’s a surprise because aye-ayes are quite an iconic species, so you would think it would have been reported somewhere before now.”
The team conducted CT scans of the aye-aye and found that the animal’s third finger likely goes so far back into the animal’s nose that it could reach the pharynx — basically, the back of its throat.
They remain uncertain exactly why Kali would slide her finger up her nose and then lick off the mucus that came out. Though they did note the habit occurs in primates, a group of animals with particularly dexterous hands.
Possible nose-picking motivations include alleviating discomfort, getting a small amount of hydration from the mucus, or even to reduce bacteria’s ability to attach to teeth.
The unsettling video adds the aye-aye to a running list of 12 primate species that have been observed picking their noses. (Yes, humans are on that list.) It also makes the aye-aye the first member of the lemur family known to pick its nose.
Like much of Madagascar’s fauna, the aye-aye is endangered, mainly due to habitat loss. Habitat loss is the primary driver of extinction for most species, and most species are legally protected too late for their populations to recover.
The aye-aye has historically been seen with superstition, so adding a behaviour conventionally seen as a nasty habit by humans to its repertoire is not a good look. But hey, at least it’s mucophagy instead of coprophagy (which you may want to avoid looking up altogether).