Why do humans have chins… and no other animals do?
It’s one of the strangest little features on your face — and scientists still aren’t entirely sure why it’s there. In this episode, we explore what a chin actually is (hint: it’s more complicated than you think), why it’s unique to humans, and what new research suggests about its origin.
It’s a short, curious look at one of the most human things about being human… and a reminder that evolution doesn’t always follow a plan.
Transcript
Welcome to Squizz Kids Science Shorts, the show where we take your big curly questions
and unpack the science stories everyone's talking about.
Break them down into snack size, science-powered answers, we sort the fact from the fluff, keep
it fun, keep it fast, and whether it's happening in your body, your backyard, or the big wide
universe, we're here to explain the science behind the headlines.
If you're near enough, take a look at your face in the mirror for a second.
Right there at the bottom, that little sticky outie bit, your chin.
Here's the strange part, no other animal on earth has one like ours.
Not lions, not monkeys, not even chimpanzees, and there are closest relatives, which leads
us to the question, why are humans the only animals that have a chin?
First, let's clear something up, a chin sounds like a simple thing right, but scientists
don't actually agree on exactly what it is.
It's not just one neat feature you can point to, instead it's more like a bunch of tiny
changes in your lower jaw or working together, kind of like you know it when you see it.
What we do know is this, chins are such unique human features that
scientists use them to identify human fossils.
If they find a skull with a proper chin, chances are it's homo sapiens.
So what's it for?
Over the years, scientists have come up with a few ideas, maybe it helps strengthen the
jaw when we chew.
Maybe it's linked to speech, helping anchor the tongue muscles, or maybe it's about attraction.
Some people prefer a strong chin, all good ideas, but here's where things get interesting.
A new research suggests that the chin might not be for anything at all.
Yep, your chin might be what scientists call, here's a new word, a spandrel.
SPANDREL, a feature that appears as a side effect of something else.
Think about baking a cake, you didn't set out to make crumbs, but once the cake's there,
the crumbs just come with it.
The chin might be a bit like that.
As humans evolved, a few big things were happening at once.
We started walking upright, our brains got bigger, our faces got smaller and flatter.
When all those changes reshaped our skull, the front of the lower jaw didn't shrink
in a perfectly smooth way, and you were left with a chin.
So instead of evolution carefully planning and saying let's give humans a chin for this
specific job, it might be more like all everything's working, so we'll just keep it that way.
Because evolution doesn't always follow a blueprint, sometimes something isn't causing problems,
it simply stays.
So next time you catch your reflection, take a look, that little bump on your face might
not be there for anything, but it tells a story about how humans became human, and it
leaves us with one last question to chew on, what other features might also be evolution's
crumbs.
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