Hi, welcome to the show. I'm Mackin, this is Species, and today we're going to look at a mystery that will leave you stroking your chin.

Why do you have one? Why did we evolve chins? This is a bonus episode unlocked by the generous donors who donated enough money that I could take time to explore an animal-related thing that is too far off the main road for a normal species-specific episode.

Humans are animals, and if I ever do an episode on us, I probably won't have time to touch on our chins in depth.

So, I decided I'd do it now. Here you go. I hope you enjoy.

It's fun to think about what makes humans special, but if you think about it for too long,

you'd start to think we're not so special at all.

Opposable thumbs?

Not that uncommon. Most primates, many marsupials, even some amphibians have them.

Bipedalism?

Well, unless you think kangaroos and ostriches should share the human pedestal, then no.

Biggest brains? Again. No. Whales and elephants beat us

dramatically in size, and it's not about ratios either, because ants beat us in the brain-to-body

ratio. More importantly, all of these traits, opposable thumbs, bipedalism, large brains, are shared with our extinct cousins, the Neanderthals.

In fact, the Neanderthals likely had larger brains than humans, and they were physically more robust.

So why did they go extinct, while we went on to global dominance?

What set us apart from them?

It turns out there's one physical trait that set us apart from our closest relatives and the rest of the animal kingdom,

and it's been sitting under our noses the entire time.

We have chins. They do not.

Let me emphasize this point. We are the only animals on earth who possess these strange lumps under our mouths. I say strange because nobody knows exactly why we have them. Sure, there are a few

theories for why they exist, but none of them are satisfactory from a scientific standpoint,

and today I'm going to talk about all these theories. Evolutionary anthropologists James D.

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