Monkeys Speak With an Accent; Clue to Early Human Language?
SUWANEE, Ga. (AP) _ A little monkey named Profanity not only knows how to scream, ″Help, I’m being bitten 3/8″ - she can say it with an accent.
Not in English, of course.
But the two scientists who interpret her screams say Profanity and other pigtail macaque monkeys can tell each other specifics about danger and, through their accents, let them know which monkey is in trouble.
This complex speech could be key to understanding the birth of human language, another scientist says.
″A primary component of language is the ability to name things and how things function,″ said Sarah Gouzoules, a behavioral biologist at the Yerkes Primate Research Center north of Atlanta. ″Monkeys have that ability.″
In addition, each family of monkeys speaks in a different dialect or vocal signature.
″How they acquire these signatures and how they learn their language gives us insight into early man,″ said Gouzoules’ husband and research partner, Harold Gouzoules.
Scientists have long known that monkeys and other intelligent mammals screech at danger. Those alarm calls were long thought to be just indications of emotion.
Then researchers made a critical discovery: Monkeys had different screams for different kinds of danger. One sound might indicate a leopard lurking nearby while another would pinpoint a human threat.
The Gouzouleses discovered that monkeys use various types and frequencies of sound to say specific things, from a whiny ″Mom, my sister pushed me″ to a frantic ″A big strange monkey is biting me 3/8″
But monkeys hearing those cries in the leafy jungle, where they can’t see the victim, need still more information before they decide to intervene. For example, a mother would rush to the aid of her child more quickly than she’d help a neighbor.
That’s where the dialect comes in. Much as Southerners have subtle differences in accent - the twang of the Tennessee mountains compared with the syrup of New Orleans - so do families of monkeys.
″The way they scream, the accent they use, lets other monkeys know which family they’re in,″ Gouzoules said.
This dialect isn’t discernible to the untrained ear, but the Gouzouleses know it. They can assign a scream to a family with 90 percent accuracy.
The Gouzouleses, who have spent two decades studying monkey speech, first documented social screams among rhesus monkeys.
Now they’re researching five large families of pigtail macaques who live together at Yerkes because these gentle, yellow monkeys, used as coconut pickers in their native Thailand, are far more socialized.
They’ve documented the dialects using highly sophisticated technology that turns sound into pictures. It shows that each family speaks with differences in frequency, tone, pitch and harmony.
They don’t know yet whether the accents are genetic or learned. They plan to let one monkey family raise another family’s baby to see which accent the baby gets.
″Social information being symbolically represented in calls provides us with antecedents of human language that we simply did not know were there,″ said Peter Marler of the University of California at Davis, a pioneer in the field.
No animal besides humans is known to be able to learn another language in nature - although primates can under intense human training. If monkeys can learn another dialect, ″we may have to revise that opinion,″ Marler said.
Monkeys are very hierarchical - there are upper-class and lower-class families and each family member is ranked, the Gouzouleses said.
Screams during a challenge convey whether the aggression is serious or minor, whether a higher-ranking or lower-ranking monkey is the aggressor and, through the dialect, which family member is being attacked.
″The more we study calls, the more amazed we are at how complex primate vocal communication is,″ Ms. Gouzoules said. ″We’re only beginning to scratch the surface.″