'Flehmen' is an exaggeration in elephants, while underplaying the reality of their vomeronasal dexterity

@paradoxornithidae @matthewinabinett @tonyrebelo @jeremygilmore @botswanabugs @ldacosta @maxallen @jwidness @ptexis @christiaan_viljoen @zarek @dejong

The vomeronasal organ (https://en.wikipedia.org/wiki/Vomeronasal_organ) performs chemical perception (https://link.springer.com/article/10.1007/BF00987849).

It is, by definition, located on the partition between the nasal cavity and the buccal cavity, allowing access from

  • above, via the nostrils (nares), or
  • below, via the mouth, or
  • both.

(The vomeronasal organ is discernible in the human foetus. However, it is regarded as relictual/vestigial, and probably functionless, in most adult individuals of Homo sapiens, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6050168/#:~:text=The%20vomeronasal%20organ%20(VNO)%20is,of%20the%20accessory%20olfactory%20system.)

In many mammals, vomeronasal perception is associated with flehmen (https://en.wikipedia.org/wiki/Flehmen_response and https://link.springer.com/chapter/10.1007/978-1-4757-9652-0_5).

In the literature, elephants (https://en.wikipedia.org/wiki/Elephant) are regarded as expressing flehmen (see references below).

This would be remarkable, because

Actually, I see scant evidence that elephants express flehmen. This has been misrepresented in the literature.

However, the reality is even more remarkable.

This is that elephants use the vomeronasal organ in an uniquely direct and precise way, among mammals.

Crucial to realising that 'flehmen' is a misnomer in elephants is that this term refers to peculiar facial expressions, not events of sensory application as such.

This can perhaps best be explained by comparing elephants with mice.

Both rodents and proboscideans clearly possess a vomeronasal organ, even in adulthood.

In both cases,

  • the organ is embedded in a bony partition which is simultaneously the floor of the nose and the roof of the mouth, and
  • it is accepted that the organ is specialised for intermittent perception of substances of sociosexual significance, such as hormones/pheromones.

However, flehmen is unrecorded in rodents. There is no particular facial expression or posture associated with vomeronasal sensing. Instead, it seems that rodents merely inhale substances of interest via the nose, or lick them, or both.

If 'flehmen' or 'the flehmen response' were a sensory event, the literature would surely regard rodents as qualifying for flehmen. However, as far as I know, no author has made such a claim. Instead, the literature seems, at least tacitly, to acknowledge that flehmen is absent in rodents, in contrast to e.g. lagomorphs and hedgehogs.

The facial expression/posture of elephants, when applying the vomeronasal organ, has little in common with flehmen in ungulates, carnivores, lagomorphs, etc. Instead, it seems identical to that of simply placing a food-item, or drinking water, in the mouth.

So, how can flehmen be claimed in elephants?

The action of elephants in placing the proboscis in the mouth does not necessarily qualify as a facial expression in the first place, let alone flehmen. And it shares none of the diagnostic aspects of a flehmen expression, mentioned in the text of a previous Post (https://www.inaturalist.org/posts/87153-why-have-two-coexisting-bovids-the-sable-antelope-hippotragus-niger-and-lichtenstein-s-hartebeest-alcelaphus-lichtensteini-diverged-in-vomeronasal-flehmen-expression#).

It is perhaps unsurprising that elephants use the tip of the proboscis to place substances of interest directly at the vomeronasal location on the roof of the mouth.

However, what seems misleading - and incorrect - is that the term 'flehmen' has been stretched to include this action of the proboscis, on the basis of context.

Such conflation tends to deplete the term 'flehmen' of meaning, while at the same time obscuring something more worthy of recognition.

I refer to the following possibility:
Elephants may be the only mammals that - in partial emulation of snakes and lizards (https://www.sciencedirect.com/science/article/abs/pii/S000334720580380X and https://onlinelibrary.wiley.com/doi/abs/10.1002/jez.1402490206 and https://www.jstor.org/stable/1565343 and https://www.jstor.org/stable/4601387) - dexterously procure samples of interest and then place them directly at the vomeronasal location.

This is as opposed to the relatively awkward approach of merely inhaling by mouth, or taking urine into the mouth and then inhaling by mouth.

Once we appreciate the approach taken by elephants, a new question arises, as follows.

Why is it that even those mammals with relatively long and 'dexterous' tongues have not been recorded sampling substances of sociosexual interest with the tongue-tip, and then placing the tongue-tip at the vomeronasal location?

This question applies particularly to



















Posted on December 04, 2023 04:12 AM by milewski milewski


@capracornelius @paradoxornithidae @beartracker @ludwig_muller


I found the following (https://coyoteyipps.com/2020/01/15/gaping/) for the first time today.

This seems to be an excellent website.

More particularly, here we have three clear photos of Canis latrans 'gaping' in a sociosexual context, which seems to be a canid version of flehmen.

I found it noteworthy that this expression differs from flehmen in Felidae (https://www.petmd.com/cat/general-health/cat-sneering-what-flehmen-response).

Instead of emulating a fang-baring expression (https://www.flickr.com/photos/cirdan-travels/28235867727 and https://www.youtube.com/watch?v=pG-ZVI8lf-I and https://photos.willbl.com/leopard-flehmen-response/ and https://www.facebook.com/WildDaZeMovie/photos/a.692710587417112/3688928381128636/?type=3), 'gaping' in C. latrans simply emphasises the wide opening of the mouth.

Posted by milewski 6 months ago

This is interesting! Had no idea Canids did this.

Posted by beartracker 6 months ago

I like these links. I am looking into scent marking for a presentation next year.

Posted by beartracker 6 months ago
Posted by milewski 5 months ago


Possible stotting in Hippotragus niger (also note open mouth, with loose gape):


Posted by milewski 5 months ago

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