Pick your nose, animals do it too

Rhinotilepsy (commonly called “picking your nose”) is a common behavior in humans that remains understudied, however. Evidently, it’s not a very popular topic – almost a taboo . To make it more “human” and accepted, as is usually done, an attempt was made to investigate animals. Well, if this habit is studied and analyzed in the animal world, it is evident that it is quite manifest: several species of primates have been caught with their paws in their noses and, not satisfied, all or almost all of them ingestwhat they find after this careful exploration of the nasal cavities. All this suggests that, given the minuteness, it is a behavior that is not expressed only out of boredom or habit, but can actually be beneficial. In a recent study, published in the “Journal of Zoology”, the primate species in which this behavior has been observed are documented and the first case of this behavior in a primate species or, better, in one of the two suborders is also presented belonging to the Primates, the Strepsirrhini, of which the lemurs belong. The name of the two suborders already suggests that the nose is a great protagonist: these species are, in fact, classified according to the shape of their noses: in the case of the suborder to which lemurs belong, we know that it derives from the Greek  strepsis“curvature”, rhís ,  rhinòs , “nose”, i.e. with a curved nose, in reference to the main characteristic that distinguishes them from the suborder of the Haplorrhini, which instead have a pointed nose (for example the vervet).

The benefits of picking your nose

In the study, the main object of analysis is a video in which this species of nocturnal lemurs that live only in Madagascar (the so-called aye-aye or aiè-aiè or chiromi, Daubentonia madagascariensis Gmelin, 1788), dedicate themselves to their nasal explorations : the lemurs, taken in these scenes of daily life, insert their very long, tapered and very mobile middle finger into the nasal cavities and then lick the collected mucus.

The same finger they use to clear hollow branches when they hunt for grubs. To understand how it is possible how the animal is able to introduce the entire finger into the cavity, the researchers have deepened the study of the internal anatomy of the nasal cavity of the aye-aye, and it turns out that it even reaches the pharynx. The study shows that this behavior is present in at least 12 primate species, most of which show some ability to carry out this practice. Once it has been ascertained that it is also a habit in animals, the objective of the scholars is to understand if and what are the benefits associated with rhinotilepsy.

Comparative studies examining mucophagia in other primate species and in vertebrates in general can shed light on its evolution and possible functional role , so as to make anyone caught picking their nose, animals (who already they do without shame) and human, above all.