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

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

Written byJack Knudson

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