Only Humans Have Chins -- and They Emerged as an Evolutionary Accident

[Judi Lynn]

Learn how the chin became an evolutionary byproduct that's unique to humans.

Written byJack Knudson

Published Feb 12, 2026, 3:55 PM
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Updated Feb 13, 2026, 10:15 AM
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3 min read

Most components of the human body have been driven by natural selection to ensure our species’ survival — the chin, though, is not one of them. Chins are uniquely human, since no other animals have them, not even chimpanzees, our closest relatives. It might seem that they would grant some sort of advantage that only we have, but research on the evolution of chins says otherwise.

A new study published in PLOS One has shown that the chin may have emerged by pure coincidence. Rather than natural selection driving the development, the chin developed in modern humans as an accidental byproduct following long-term evolution of the jaw in early hominins. As a result, the chin wasn’t really designed for a true purpose, shaking up conventional views of humans’ physical characteristics.

“Just because we have a unique feature, like the chin, does not mean that it was shaped by natural selection to enhance an animal’s survivability, for example a buttress for the lower jaw to help dissipate the forces of chewing,” said study author Noreen von Cramon-Taubadel, a professor of anthropology at the University at Buffalo, in a statement. “The chin is likely a byproduct, not an adaptation."

The Chin as an Evolutionary Accident

Human faces wouldn’t look complete without a chin, anatomically defined as a bony protrusion that extends from the lower jaw. Previous studies suggested that chins evolved in humans as a way to resist biomechanical stresses related to mastication, or in simpler words, chewing.

More:
https://www.discovermagazine.com/only-humans-have-chins-and-they-emerged-as-an-evolutionary-accident-48689

[Kira_Thomsen-Cheek]

1. Fascinating!

And very cool. Thanks for posting this!

[Goonch]

7. ;-{)....

[twodogsbarking]

10. First thing I thought of. Thanks for posting.

[brer cat]

2. Very interesting article. I must say I have never given

thought to why we have chins.

[NJCher]

3. This led me to

Reading about lantern jaws.i think Epstein has one.

Otoh, we have Bezos, who just bought himself a new chin.

[William Seger]

4. I'm a big fan of evolutionary biologist Stephen Jay Gould

One concept that he discussed frequently was the idea that not all features of organisms are (or need to be) explained by natural selection for advantageous characteristics, that some features just happen by random chance and are carried forward by species that are successful for other reasons. He called it the "contingency" principle of evolution, and I think of it every time I see someone trying to explain every characteristic of an animal as somehow an evolutionary advantage — there's no logical reason to expect that.

[AZ8theist]

5. "The chin is an Evolutionary Accident"......

You know what else is an "evolutionary accident"?


MAGATS.

[BigmanPigman]

6. Except for tRump's DNA.

He and all of his children have inherited their father's weak chin and too small mouth and he HATES IT!

After Tiffany was born he looked at her and said, "She has my chin and mouth" with disdain.

Ivanka got a chin implant. The sons wear beards to hide the fact.

[Maraya1969]

8. So I wonder how I would have landed when I fainted and went straight forward and on my chin

if I didn't have a chin. I've since had to have a handful of physical therapy sessions for TMJ because of the injury to my CHIN! It seems I would have gone flat on my face maybe.

[GreenWave]

9. Because we do not eat enough roughage as nature intended

our jaws do not become prognathous enough to allow our back molars to sink in properly.

This chewing must take place in the very early years while bones are still growing.

Remembering my anthro lecture from Dr. Gavin

https://historicimages.com/products/nob16925

[twodogsbarking]

11. Keep your chin up. How dat?

[Goonch]

12. ;-{)......