This is scientific American's 60 second science. I'm Christopher Intagiyata.

The animal kingdom is crowded with species that use sound, growls and bellows and

roars to signal size. Dogs do it, red deer do it,

koalas do it. And now we can add humans to that list.

Because a new study suggests we can size up other people by the sound of their roar alone.

First, researchers took the circumference of 61 men's and women's biceps, measured their

grip strength and their height.

Then they told them to let loose a roar.

I've probably described it as the most hellish version of Groundhog Day that you can think of.

Jordan Rain, a behavioral orthologist at the University of Sussex.

If you just imagine 30 actors in training coming into a small room one after another and roaring at you.

Yeah, it was an experience, that's for sure.

His team then played those roars back to a separate group of male and female listeners who had also been measured for strength

and size. They found that men correctly rated other men as substantially stronger than

them 90% of the time, based on roar alone. Men did tend to underestimate women's strength by the sound of their

roars, and women overestimated men's strength. But in general, roaring like a wild animal,

it seemed like a pretty accurate way to telegraph body size and strength.

The researchers also found that regular shouting,

That's enough! I'm coming for you!

Did not seem to have the same effect as a roar.

So what the roaring is actually doing is having this ex-exaggerative effect on strength,

which is very similar to the adaptations that non-human mammals possess that allow them to

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