美国国家公共电台 NPR Orangutan's Vocal Feats Hint At Deeper Roots of Human Speech

STEVE INSKEEP, HOST:

Scientists are finding clues about the origin of human speech thanks to a very unusual ape. NPR's Jon Hamilton reports on an orangutan named Rocky.

JON HAMILTON, BYLINE 1: A half-dozen orangutans are relaxing in a sun-filled atrium at the Indianapolis Zoo. Then they notice Rob Shumaker. He's the zoo's director, and he's got treats.

ROB SHUMAKER: When we have special visitors like today, we do...

ROCKY: (Vocalizing).

SHUMAKER: ...Really bring treats. Oh, that's Rocky - Rocky trying to get my attention to come over and...

ROCKY: (Vocalizing).

SHUMAKER: Hold on, bud. Hold on. Hold on.

HAMILTON: All the orangutans want some sugar-free jelly beans and a juice box. But Rocky, who is 12 and still an adolescent, is by far the most vocal 2 and persistent 3.

ROCKY: (Vocalizing).

SHUMAKER: What?

ROCKY: (Vocalizing).

SHUMAKER: You've had everything.

ROCKY: (Vocalizing).

SHUMAKER: That's it. You've had everything.

HAMILTON: Shumaker calls these vocalizations wookiees because they sound like the "Star Wars" character Chewbacca.

(SOUNDBITE OF FILM, "STAR WARS: EPISODE VI - RETURN OF THE JEDI")

HARRISON FORD 4: (As Hon Solo) Keep your distance though, Chewie, but don't look like you're trying to keep your distance.

PETER MAYHEW: (As Chewbacca) (Vocalizing).

FORD: (As Han Solo) I don't know. Fly casual.

HAMILTON: Rocky is the only orangutan known to make these sounds. In the forests of Borneo and Sumatra, orangutans tend to sound like this.

(SOUNDBITE OF ORANGUTAN VOCALIZATIONS)

HAMILTON: But Shumaker says Rocky didn't grow up in the forest. He grew up in Hollywood.

SHUMAKER: A number of years ago, he was certainly the most visible orangutan in entertainment at the time - TV commercials, things like that.

(SOUNDBITE OF AD)

UNIDENTIFIED ACTRESS: (As character) Hey, boss, do we have Aflac?

UNIDENTIFIED ACTOR: (As character) No, we have...

ROCKY: (Vocalizing).

HAMILTON: Rocky's work meant he grew up without his mother and spent much of his time with people. Shumaker says that may be why Rocky developed a special Wookiee call for his human friends.

SHUMAKER: He most often uses it when he would like someone's attention.

HAMILTON: The first time Shumaker and other scientists heard Rocky making his Wookiee sound, they were really surprised.

SHUMAKER: Because we had never heard it before from any other orangutan, we assumed then that it had to be learned. If it was learned, it had to involve voluntary control of his vocal folds or what people call voice box.

HAMILTON: Humans are masters at controlling the voice box and imitating sounds. But an ape wasn't supposed to have that ability. To find out for sure what Rocky could do, the team did an experiment. They asked him to imitate one of the scientists.

SHUMAKER: She would vary the frequency high or low.

(SOUNDBITE OF ARCHIVED RECORDING)

UNIDENTIFIED WOMAN: Haaa (ph).

ROCKY: (Vocalizing).

SHUMAKER: He would vary the frequency high or low.

(SOUNDBITE OF ARCHIVED RECORDING)

UNIDENTIFIED WOMAN: Haaa (ph).

ROCKY: (Vocalizing).

SHUMAKER: Slightly to our surprise - not totally - slightly to our surprise, he was matching things perfectly 5.

HAMILTON: Adriano Lameira of Durham University in the U.K. says that experiment revealed something really important about the origins of human speech.

ADRIANO LAMEIRA: The type of control that we need to produce our vowels 7 and learn our vowels, it is already present in great apes.

HAMILTON: So is the ability to produce consonants 9. Lameira discovered that a couple of years ago with an orangutan named Tilda. She was able to replicate 10 the rhythms of human speech.

(SOUNDBITE OF ARCHIVED RECORDING)

TILDA: (Vocalizing).

HAMILTON: Together, Rocky and Tilda make the case that orangutans can manipulate the building blocks of speech. That may not sound like a big deal. After all, parrots can speak entire sentences. But we evolved from ape-like ancestors, not birds. And for decades, there's been a debate about whether humans' ability to speak appeared suddenly or evolved slowly from abilities found in other primates 11.

Lameira says that debate persisted because scientists were unable to answer a simple question.

LAMEIRA: If the control of the voice is so fundamental, if this is so crucial, why we're not seeing in our closest relatives?

HAMILTON: Now that we are, Lameira says it's time to focus on a new question.

LAMEIRA: Why did our ancestors about 10 million years ago piece together the first consonant 8 with the first vowel 6 to make up the first syllable 12 or the first word?

HAMILTON: In other words, what was their motivation? That's still a mystery. But Lameira says it's pretty clear what motivates Rocky. He wants to connect with his human friends.

LAMEIRA: He's so into it. He wants to perform so well so badly that we really need to sort of calm him down and give him hints that he's not being judged according to his performance.

HAMILTON: Rob Shumaker says Rocky understands a lot of words but still doesn't speak any.

ROCKY: (Vocalizing).

SHUMAKER: Hold on, Rock. Hey, hold on, man.

HAMILTON: At least not yet. Jon Hamilton, NPR News.