Science & Technology
Why are we the only species with a chin ?
By T.K. Randall
January 31, 2016 · 32 comments
Why do we have a chin and what is it used for ? Image Credit: sxc.hu
It might not be immediately evident, but humans are actually the only animals on Earth with a chin.
The humble chin is such an obvious part of our facial anatomy that most of us simply take it for granted and don't think much about it, yet for years scientists have been attempting to answer a single, fundamental question about this peculiar strut of bone - why do we have it ?
No other species has a chin, not even other primates such as gorillas and chimpanzees which instead have a lower jaw that slopes backwards from their front teeth.
Our extinct ancestors, despite being very similar to us, did not have a chin either.
"It's really strange that only humans have chins," said Duke University's James Pampush.
"When we're looking at things that are uniquely human, we can't look to big brains or bipedalism because our extinct relatives had those. But they didn't have chins."
One theory is that the chin evolved to help support the lower jaw while chewing, however studies have suggested that, due to the way the jaw works, the chin wouldn't help at all in that regard.
Other possibilities include the idea that the chin helps reinforce the jaw when we talk or that it is a physical feature designed to help attract a mate, but so far nobody can agree on any one answer.
"The chin is one of these rare phenomena in evolutionary biology that really exposes the deep philosophical differences between researchers in the field," said Pampush.
And no, despite popular belief elephants don't have chins - they have very different lower jaws to ours and their chin-like protrusion actually acts as an anchor for their fleshy lower lip.
"For these reasons, it is generally agreed that whatever the biological situation occurring on the front of the elephant lower jaw, it is fundamentally different from the condition in humans," said Pampush.
"It may provide some insights into the situation in humans, but to call it a 'chin' stretches the definition."
Source: The Atlantic
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