In Africa, Decoding the "Language" of Elephants
D. L. Parsell
for National Geographic News
|February 21, 2003|
It's a safari postcard moment: A family of elephants rush together, rumbling, trumpeting, and screaming, their chorused voices deafening in the wilderness.
To casual observers, the sight is pure animal theatrics, and thrilling testimony to the magnificence of Africa's wildlife. But biologist Joyce Poole knows there's a lot more happening than meets the ear.
For 27 years she has lived among savanna elephants in Kenya's Amboseli National Park studying their behavior and methods of communication. Poole has found that the elephants use more than 70 kinds of vocal sounds and 160 different visual and tactile signals, expressions, and gestures in their day-to-day interactions.
Like humans and many other mammals, she explained, the elephants have a wide range of calls and signals for different purposesto secure their defense, warn others of danger, coordinate group movements, reconcile differences, attract mates, reinforce family bonds, and announce their needs and desires.
Distinctive expressions of joy, anger, sympathy, sexual desire, playfulness, and many other emotions are among their vocal repertoire.
Poole and others have found that the elephants not only trumpet their calls but squeal, cry, scream, roar, snort, rumble, and groan.
Calls range from as soft as a whisper to more powerful than a jackhammer; from as abrasive as a rooster's crow to fluid as water gurgling and pulsating through an underground tunnel. Some of the sounds are so low-pitched they aren't audible to human ears.
"Elephants are extremely exuberant and expressive animals," said Poole, an American who grew up in Kenya and returned as a student researcher in 1975. "The emotion and energy in groups when they come together after they've been separated is incredibly powerful. That kind of behavior occurs in many situations."
Under a three-year program known as the Savanna Elephant Vocalization Project, Poole and her team are compiling a lexicon of the different kinds of calls used by the Amboseli elephants.
Poole's research is part of the Amboseli Elephant Research Project, launched in 1972 by renowned elephant researchers Cynthia Moss and Harry Croze. Amboseli is a 150-square-kilometer (57-square-mile) park in southern Kenya near the border with Tanzania and near Mount Kilimanjaro,
The project, which is affiliated with the Kenya Wildlife Service, it is longest-running study of free-living elephants in the world.
Studies at Amboseli by more than a dozen researchers have produced a comprehensive picture of elephant family life, behavior, and communication. The project has collected an extraordinary amount of data on individual members of the park's population of a thousand elephants.
The work of Poole and other elephant researchers is needed to plan effective programs for elephants' survival.
In the mid-1980s, for example, Poole and biologist Katy Payne of Cornell University discovered that elephants communicate in part through calls with infrasonic components, very low-frequency noises that can be detected as far as a mile or more away.
Today, Payne and other researchers are using this knowledge to develop ways of acoustically monitoring and studying forest elephants in central and West Africa. They are in grave danger from poaching because of the quality of their ivory, but they are so reclusive that little is know about them, which makes conservation planning difficult.
The biggest challenge related to the protection of savanna elephants (Loxodonta africana), said Poole, is how to reconcile conflicts arising from human competition for access to their habitat as a result of population growth and poverty.
Scientists say elephants have an elaborate system of communication because they need it to maintain a complex social structure based on strong family relationships.
Adult male elephants live and travel alone or in loose association with other bulls, while elderly females (matriarchs) head family groups consisting of other female relatives and their young. These female units are organized into a structured system of bond groups and clans and usually stay together for life.
"Like primate social grooming, elephants use vocalization to reinforce bonds that hold the group together," said Poole. "We see this happening several times a day."
Katy Payne has observed that elephants "are as emotional and attached to family members as human beings are, and are very much aware of the experience of others."
The male and female elephants have developed distinctive calls that are adapted to their different roles.
Like humans and other highly social species, the savanna elephants depend on a large repertoire of calls and other methods of communication to interact appropriately with others and exchange important information relevant to their welfare and survival.
Besides using vocal sounds, elephants also communicate through touch, sight, and chemical signals.
Stanford University biologist Caitlin O'Connell-Rodwell has found, for example, that elephants appear to communicate in part by sensing seismic vibrations through their feet, with the soft skin on the pads of their feet acting like the head of a drum.
A well-developed communication network is even more crucial for elephants because individuals and groupsperhaps mates, relatives, or friendsroaming their native habitats are often far apart from one another.
Powerful infrasonic calls enable them to send messages and warnings, sometimes over long distances. The elephants, said Poole, are sending messages such as "Hello, I'm here. Where are you?" "Help, I'm lost." "I'm ready for a mate." Or "We are a force to be reckoned with."
Wide Repertoire of Calls
In developing a systematic catalog of known elephant calls, the Savanna Elephant Vocalization Project draws on voluminous information collected from years of field studies in Amboseli.
The team logged many of the various calls made by individual elephants and recorded details such as when, where, and under what social conditions they occurred. The different sounds are being recorded on disk; still images and video films are also being made to show the elephants' behavior during the calls.
Poole is measuring characteristics of the call such as frequency, bandwidth, and duration to differentiate them.
Samples of about 80 percent of the different known calls have been collected. "We have a huge task to measure and analyze the calls and to describe the contextual information," said Poole.
One of the calls identified so far is what Poole describes as the "let's go" rumble, which is used to suggest "I want to go in this directionlet's go together." A drawn-out rumbling, it lasts about five to six seconds and is usually repeated about every 80 seconds or so until the caller gets results.
Another is the "contact call." An elephant calling for a distant family member emits a powerful reverberating sound and then lifts its head and spreads its ears listening for an answer. If it receives one, it responds with an explosive sound.
"What I think goes on in these long distant calls," said Poole, "is an elephant gets an answer and then it responds, 'We're in touch.' "
Cornell University's Bioacoustics Research Program has provided technical assistance to the project. Its archives unit, the Macaulay Library of Natural Sounds, plans to make the results available electronically to aid conservation, education, and scientific research.
Greg Budney, a curator at the library, said the information will be included in a series of multimedia Web sites now being developed that focus on acoustic communication among elephants, humpback whales, and other "sonically rich" species.
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