This is Scientific American 60 Second Science.

I'm Cynthia Graber.

Got a minute?

Imagine the evolutionary advantage of being able to hear a predator rustling in the tall grass

nearby or in the tall grass nearby

or in the ability to hear a comrade making a chch-ch sound

to warn you about that predator.

Now a study finds that early human species

may have had sharper hearing in certain frequencies than we enjoy.

The finding is in the journal Science Advances.

We've been able to reconstruct an aspect of sensory perception in a fossil human ancestors

known as Australopithecus Africanus and Parenthus robustus from South Africa.

Binghamton University Anthropologist Ralph Quam.

Both of these fossil forms lived about 2 million years ago and represent early human ancestors.

We took CT scans of the skulls.

We created virtual reconstructions on the computer of the internal structures of the ear that will

predict how an organism hears based on these measurements of its ear. And the

Reconstructed Physiology reveals that those early homonyms likely heard differently than both modern chimps and modern humans.

Specifically, the homonyms were probably more sensitive to frequencies associated with sounds like tkf and s.

We're not arguing they had language but we think our results do have

implications for how they communicated.

And the finding is that this hearing pattern would have been beneficial if you were engaging in short-range vocal communication in an open environment.

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