Why so many species eat their snot? – Journal of Zoology Weblog


Fabre, A.-C., Portela Miguez, R., Wall, C.E., Peckre, L.R., Ehmke, E. and Boistel, R. (2023). A evaluation of nostril choosing in primates with new proof of its prevalence in Daubentonia madagascariensis. Journal of Zoology, vol. 319, pp. 91-98. https://doi.org/10.1111/jzo.13034

Illustration of the interior construction of an aye-aye choosing its nostril. ©Renaud Boistel

Did you ever wonder if different species (in addition to people) choose their noses and eat their snot? This query first crossed my thoughts after I witnessed this conduct whereas filming an aye-aye on the Duke Lemur Heart. I used to be disgusted and impressed concurrently I watched Kali (let’s name her by her title) put all the size of her actually elongate third finger up her nostril (Determine 1).

Determine 1. Kali places the entire size of her third finger, which may be very lengthy, into her nostril. (©Renaud Boistel and Anne-Claire Fabre)

The place was that finger going? For those who don’t know what the hand of an aye-aye seems to be like, I encourage you to take a look at Determine 2. And sure…. the hand of the aye-aye is actually uncommon and extremely specialised. The third and fourth fingers are elongated and extremely cellular, and make up about two-thirds of the size of the hand (the hand itself makes up over 40% of the entire size of the forelimb)!!! Aye-ayes use their third finger to seek out meals by tapping on wooden, which generates acoustic reverberations permitting them to seek out scrumptious grubs dwelling within the wooden (extra data on that on this fantastic video True Info about The Aye Aye) and when that lengthy finger is put into their nostril… they discover snot too!

Determine 2. The one on the left is an aye-aye observing you; the one on the best is an aye-aye consuming an orange and never you. Sure, the aye-aye likes to eat oranges like we do, and sure, issues that appear to be bizarre, furry spiders are the palms of the aye-aye. (© David Haring and the Duke Lemur Heart)

My first response was to ask my collaborators Erin Ehmke and Christine Wall, primatologists on the Duke Lemur Heart, in the event that they knew about nostril choosing behaviors in aye ayes and different primates. It’s from these discussions that this research began, the crew of collaborators rising progressively with complementary  abilities: Renaud Boistel who studied the 3D anatomy of the top in relation to the finger with the intention to perceive the place the finger goes when the aye aye picks its nostril; Roberto Portela Miguez who helped me conduct bibliographical analysis; and Louise Peckre who’s a specialist in primate prehensile conduct and helped with the interpretation and dialogue on the findings on this paper.

We had been first struck by the paucity of literature on the topic! Nearly the entire literature consists of both behavioral observations or psychological surveys of people. As well as, many of the data, papers, and books discovered on-line are jokes. Due to this fact, a primary step of sorting the data needed to be accomplished with the intention to preserve solely the related ones. What have we discovered from this literature evaluation?

1) Difficult time period to speak in regards to the act of choosing one’s nostril (rhinotillexomania, bless you…), consuming nasal mucus (mucophagy).

2) The composition of a snot (see Determine 3): primarily water: Thirsty?

Determine 3. Nasal mucus composition.

3) At the very least 12 primate species choose their nostril (people, chimpanzees, bonobos, Western Gorillas, Japanese Gorillas, Sumatran Orangutans, crested macaques, crab-eating macaques, tonkean macaques, white-fronted capuchins, bearded capuchins, and aye-ayes)

4) Choosing your nostril isn’t socially accepted (regardless that the vast majority of individuals do it, sure… you’ll need to admit it! Don’t be ashamed!) and it’s a pretty latest cultural phenomenon.

5) Over 10 years in the past, a researcher wrote a e book chapter on the identical matter (Portalatin, 2009) and already famous the dearth of research on the problem and inspired extra comparative analysis. Since then, virtually nothing has been accomplished!

6) Nostril choosing can distribute nasal micro organism (dangerous… Wertheim et al., 2006) however might help to take care of oral well being (good!!! Frenckel & Ribbeck, 2015)

7) Regarding the unbelievable anatomy of the aye-aye, when it picks its nostril, its finger goes into its mouth (and doesn’t scratch its mind)! It’s similar to a really deep covid self-test in spite of everything… besides that you simply eat the… you see what I imply.

TAKE HOME MESSAGE: We don’t know whether or not choosing your nostril and consuming the nasal mucus is nice or dangerous for you. We do know that a number of species do it. WHY?  No concept… however hopefully additional comparative research reassessing this intriguing conduct will present new insights into its origin, practical position and evolution.

Don’t go away this weblog till you could have checked these references and the hyperlink to the Duke Lemur Heart web site. Aye-ayes want you and are among the sweetest and most curious species I’ve ever labored with. Their populations are extremely endangered and you are able to do one thing to assist! Undertake an aye-aye (they’re like youngsters, however very furry and with bizarre palms). -> https://lemur.duke.edu/uncover/meet-the-lemurs/aye-aye/ (©David Haring and the Duke Lemur Heart)

By Anne-Claire Fabre


Frenckel, E.S. & Ribbeck, Okay. (2015). Salivary mucins shield surfaces from colonization by cariogenic micro organism. Utilized and Environmental Microbiology, 81, 332 – 338. https://doi.org/10.1128/AEM.02573-14

Portalatin, J.J. (2009). Consuming snot. Socially unacceptable however frequent: Why?. In MacClancy, J., Henry, J. & Macbeth H. (Eds.), Consuming the inedible uncared for dimensions of meals selection (pp. 177–187). Berghahn Books. https://doi.org/10.3167/9781845453534

Wertheim, H. F., van Kleef, M., Vos, M. C., Ott, A., Verbrugh, H. A. & Fokkens, W. (2006). Nostril choosing and nasal carriage of Staphylococcus aureus. An infection Management and Hospital Epidemiology, 27, 863 – 867. https://doi:10.1086/506401

Web site hyperlink: https://lemur.duke.edu/

And once more, undertake an aye-aye: https://lemur.duke.edu/uncover/meet-the-lemurs/aye-aye/


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