It is said that elephants talk to one another, mumbling with their mouths the speech of men.
But to not all is the speech of the beasts audible, but only the men who tame them hear it."
Trainer Liz Sane and elephant Queene joined Circus Gatti in 1981 and performed for another 20 years before retiring at Wild Adventures. Dane had lost track of her childhood elephant friend until a burning desire to find out whatever had happened to Queenie led her and her son to search for her. In 2005, Dane -- now a grandmother in Concord, N.H. -- flew to Georgia to reunite with Queenie at Wild Adventures. "She remembered me," Dane said. "She had grown apprehensive of strangers, so when we first got to Wild Adventures, we approached the elephant area, (and) were separated from the elephants by a railroad tie and a cable of fence. We werent sure what we should do. She definitely showed signs of recognition. "When we saw it was safe for me to go into the enclosure, she put her Trunk
on my face and on my arm, and soon she appeared content and was rumbling, which is kind of like an elephants version of a cat purring. "You hear an elephant never forgets," she said. "Its true." Dane returned to see Queenie every year since, remaking a connection few people can claim -- visiting a childhood pet decades later.
"Elephants may be able to detect stress from a Herd
many miles away," says Caitlin O'Connell-Rodwell, an affiliate of the Stanford Center for Conservation
Biology and a postdoctoral fellow in the Department of Pediatrics.
"They may be communicating at much farther distances than we thought," adds O'Connell-Rodwell, author of the JASA study.
In the early '90s, O'Connell-Rodwell began to suspect there was more to long-distance elephant communication than airborne rumblings alone.
"I started working with elephants in Etosha National Park in 1992," she recalls. "I was observing them at a drinking hole when I noticed this strange set of behaviors. They would lean forward, pick up one leg and freeze for no apparent reason."
She theorized that the elephants were responding to vibrations in the ground from approaching Herds
"When I returned to the University of California at Davis, I teamed up with my Ph.D. adviser, Lynette Hart, and geophysicist Byron Aranson to find out if there really are seismic communications among elephants," she says.
The result was a series of geophysical experiments with captive elephants. The first one in 1997 confirmed O'Connell-Rodwell's suspicion that acoustic rumbles are accompanied by vibrations in the Earth.
"When an elephant transmits airborne low-frequency (20 hertz) vocalizations," she wrote, "a corresponding seismic wave is transmitted in the ground."
To determine how far these seismic waves propagate, O'Connell-Rodwell and her coworkers conducted experiments with two female Asian elephants at a private training facility near Jefferson, Texas.
They placed two microphones outside the elephants' enclosure one about 30 Feet
away, the other about 130 Feet.
The researchers also buried a geophone directly below each microphone to measure underground vibrations, so whenever the elephants vocalized or launched into a mock charge, the geophone/microphone pairs made simultaneous acoustic and seismic recordings of the event.
"Our results show that elephant rumbles travel separately through the air and the ground," writes O'Connell-Rodwell in the December issue of JASA.
She points out that mock charges generate airborne and seismic signals with frequencies of about 20 hertz -- ideal for long-distance communication.
"Based on our mathematical models, we estimate that seismic signals produced by elephants can travel between 10 and 20 miles in the ground, while acoustic signals have the potential of traveling only about six miles through the air," O'Connell-Rodwell observes.
"If elephants were capable of detecting the seismic information we measured, the maximum range of their airborne communication would be enhanced considerably," she concludes.