Humans are the only animals on Earth with chins and scientists are baffled at the reason why
Humans are the only animals on Earth that have chins, and that is apparently true despite it sounding entirely insane.
Pretty much everyone in the world has a chin, and some have two, but that supposedly puts us in a class of our own when it comes to animals that roam this planet.
However, there is no animal that is not a member of the Homo Sapien species that has a chin, which is a bit confusing when you think about it.
Cats and dogs, surely they have chins otherwise what would they have to enjoy you scratching them under?
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Chimpanzees, our close genetic relative, you'd think maybe they have chins as well but apparently the answer is no.
It turns out that the chin isn't entirely what you might have thought as lots of animals have a lower jawbone, the mandible, but that doesn't mean they have a chin.
The chin is only present on a human mandible and it refers to a little bit of bone jutting out of the front which pokes forward.
No other species in the world that we've yet discovered has got one of those little jutting nubs of bone on their jaw, so they don't get entry to the chin club.
The animals in this world that come closest to having a 'true chin' are the elephant and the manatee, but even they don't measure up.
Then again, as the apex predator of this planet and the only species (that we know of) to have invented the scientific study we get the privilege of deciding what counts as a chin and what doesn't.
As for why we even have chins, there are a number of theories and Dr James D Pampush has run through a few in conversation with NPR.
One such theory is that talking stresses our jaw muscles and potentially cause cracks in the jawbone, so we have chins to take the strain, but the Doc doesn't think this is why we have them.
He also discussed the idea that humans might have chins as a means of enticing potential sexual partners, but he also wasn't convinced about that as an explanation.
Then there's the suggestion that our chins are there as natural armour to block being hit in the throat, but if that was the case then they'd be doing a lousy job at defending our necks.
Ultimately the best answer we've got at the moment as to why we have chins is 'we don't know, we just do'.
Joe Harker