This is Scientific Americans Science Quickly.

I'm Star Martin.

Oh, oh, oh, oh.

That remarkable sound comes from a wild male orangutan.

He lives in the Indonesian part of the island of Borneo.

And he's looking for a mate.

His call is meant to pierce the thickly vegetated tropical pit forest, where he lives his mostly

solitary life.

What you can hear in his voice, and researchers studying these primates can detect, is that

it's now a bit raggedy, slightly hoarse.

You've heard it in plenty of classic films.

It's the Smoker's voice.

We'll get back to just where this orangutan's Smoker's voice came from in a bit.

But first, let's meet our guide.

I go to the island of Borneo that's been a pretty constant feature of my research.

This is Wendy Herb.

She's a behavioral ecologist and biological anthropologist at Cornell University.

This particular population of orangutans, we refer to that site as Tuwanan.

It's the name of the village that's right next to that forest area, where we have the

trails and the habituated animals in our little camp.

Our orangutans are known for being the most solitary of the great ape.

Despite their pension for living solo, males need to be able to communicate with females

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