Elephants And Humans Share A Unique Biological Connection

<p> Evo Flash / <a href="https://www.flickr.com/photos/evoflash/6886945016/" target="_blank">Flickr</a> (<a href="https://creativecommons.org/licenses/by/2.0/" target="_blank">CC BY 2.0</a>) </p>

Humans have often felt a kind of kinship and bond with elephants due to the level of emotion they sometimes seem to express, but it seems that there is another similarity between us and them: our chins. Featured on "QI" and having been a topic of debate for a while at Frontier London HQ, we thought it was about time to fully look into it.

Photo: Martin Fisch / Flickr / CC BY-SA 2.0

The biology

Surprising and almost ludicrous, it may sound, but it is apparently true - we are the only two species to have chins. Although there is often debate as to whether the same term of "chin" can be used for elephants, the feature is arguably the same in both species. In human evolution, the chin is a cladistic apomorphy, partially defining anatomically modern humans as distinct from archaic forms - apes have a simian shelf for example (a bony thickening on the front of the jaw to reinforce the jaw). The chin developed as a point of muscular attachment for the tiny movements of the lips, associated with speech, and the human chin is formed by the lower front of the mandible (the lower jaw).

Photo: Jeff Egnaczyk / Flickr / CC BY 2.0

The point of the chin

The chin is what makes humans unique and aides to the proof of our evolution from our ancestors. The most common explanation as to why humans have chins is that it provides a buffer against the mechanical stresses of the jaw. It is also often argued that the chin developed during natural selection of mates - the chin made the male human more attractive and so this trait evolved to become a constant feature. More recently it has been suggested that the chin developed in response to the progress of our distinctive form of speech, due to the movements of the lips and manipulation of the tongue in order to produce the sounds we know as words, the chin developed in order to support this new use of the mouth and tongue.

And some people simply like to go with the theory that we have a chin so that we may fold towels with ease.

Elephants, chins, and what it means

The fact that some scientists have determined that elephants are the only other species to have a chin has opened up a lot of debate surrounding this issue. There has even been discussion that humans and elephants appear to have evolved from similar ancestors due to the similar characteristics and anatomical likenesses we share.

It is far easier to accept that we are related to apes and chimpanzees when their bodies are so obviously similar to ours, especially when there is not a huge amount of specific evidence to prove that elephants and humans could be more closely related than previously thought. But if elephants have chins, like us, then this would most certainly be the case.

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