New evidence that elephants communicate through ground reported

<body leftmargin="0" bgcolor="#000060" text="#FFFFFF" link="#FFFF00" vlink="#FF9900"> <b> <p class="MsoNormal"><font face="Arial" size="5">Scientists report new evidence that elephants communicate underground</font></p> </b> <p class="MsoNormal"><font face="Arial" size="1">Posted May 31, 2005<br> Courtesy Stanford University<br> and World Science staff<br> </font> <b> <font size="2" face="Arial"><br> Scientists say they preliminary findings from a new study seem to confirm a theory that elephants can communicate through underground signals. </font></b> </p> <p class="MsoNormal"><b><font size="2" face="Arial">The findings might explain reports that trained elephants in Thailand became agitated and fled from the direction of the tsunai of that killed more than 200,000 people on Dec. 26. Their escape saved their own lives and those of tourists riding on their backs. <br> <br> The new findings come from ecologist Caitlin O’Connell-Rodwell of Stanford University in Stanford, Calif. </font></b></p> <p class="MsoNormal"><b><font size="2" face="Arial"> In 1997, she proposed that elephants can communicate through deep calls that generate powerful ground vibrations known as seismic signals. Earthquakes and tsunamis spawn similar vibrations. Elephants can feel the vibrations through their sensitive trunks and feet, the ecologist hypothesized.<br> <br> Scientists have long known seismic communication is common in small animals, including spiders, scorpions, as well as in elephant seals, which are unrelated to elephants. But O’Connell-Rodwell was the first to suggest that a large land animal could send and receive such messages.<br> <br> “Elephants may be able to sense the environment better than we realize,” she said, noting earlier studies showing that elephants will sometimes move toward distant thunderstorms. “When it rains in Angola, elephants 100 miles away in Etosha National Park start to move north in search of water. It could be that they are sensing underground vibrations generated by thunder.”<br> <br> Elephants may transmit signals as well as receive them, she added, but the transmissions aren’t necessarily intentional. They could the byproducts of sounds produced when elephants run, charge and sound off. <br> <br> “Perhaps they’re sending out signals to potential mates far away,” she said. “Or maybe they can tell if a predator is in the vicinity by picking up seismic cues from a distressed herd.”<br> <br> In the 1980s, scientists found that elephants emit a variety of infrasounds—calls too low in pitch to be heard by most humans—which other elephants can detect more than two miles away. Scientists believe elephants’ long-distance communications are crucial for their survival, especially where they range over large areas.<br> <br> Last July, O’Connell-Rodwell went to one such area, Etosha National Park in northern Namibia, to begin an elaborate experiment to test for seismic signaling. At the park, more than 2,400 savanna elephants range over an area larger than El Salvador.<br> <br> Her team set up camp at Mushara waterhole, a freshwater spring where elephants, giraffes, lions and other animals gather day and night to drink or bathe during the dry Namibian summer. They spent a month performing round-the-clock tests designed to see how elephant herds respond when specific calls are played back through the ground.<br> <br> The experiment was a followup on a simpler experiment performed three years ago.<br> <br> “Elephants live in matriarchal breeding herds made up of mothers, aunts and their offspring,” O’Connell-Rodwell notes. “Once males reach puberty, around age 12, they get kicked out and start traveling alone or forming small bachelor herds.” <br> <br> The search for a mate in this vast wilderness is further complicated by the elephant’s reproductive biology. Females breed when they are in estrus--a brief period of ovulation that only occurs every two years and lasts just a few days. <br> <br> “Females in estrus make these very low, long calls that bulls home in on because it’s such a rare event,” O’Connell-Rodwell said. These powerful estrus calls carry more than 2 miles in the air and may be accompanied by long-distance seismic signals, she adds. <br> <br> Breeding herds also use low-frequency vocalizations to warn of predators. Adult bulls and cows have no enemies, except for humans, but young elephants are susceptible to attacks by lions and hyenas. When a predator appears, older members of the herd emit intense warning calls that prompt the rest of the herd to clump together for protection and then flee the scene. <br> <br> In 1994, O’Connell-Rodwell recorded the dramatic cries of a breeding herd threatened by lions at Mushara waterhole. “The elephants got really scared, and the matriarch made these very powerful warning calls, and then the herd took off screaming and trumpeting,” she recalls. “Since then, every time we’ve played that particular call at the waterhole, we get the same response--the elephants take off.” <br> <br> Reacting to a warning call played in the air is one thing, but what if the elephant could only feel the call through the ground? <br> <br> To find out, the researchers used a device that converts acoustic sounds into vibrations. They buried in near the waterhole in 2002 and connected it to a tape deck installed in an observation tower.<br> <br> Every time a herd showed up at the waterhole, O’Connell-Rodwell would play a tape of the 1994 warning call, converted to a seismic vibration through the device. <br> <br> The results showed “that elephants do indeed detect warning calls played through the ground,” O’Connell-Rodwell observes. “We expected them to clump up into tight groups and leave the area, and that’s in fact what they did. But since we only played back one type of call, we can’t really say whether they were interpreting it correctly. Maybe they thought it was a vehicle or something strange instead of a predator warning.” <br> <br> (To hear actual elephant vocalizations, visit the website http://www.elephantvoices.org/index.php?topic=resources.) <br> <br> The 2004 experiment was designed to solve that problem by using three different recording: the 1994 warning call from Mushara; a different sort of anti-predator call recorded in Kenya; and an artificial warbling tone. <br> <br> This time, all three sounds were randomly played at different times to see if the elephants could recognize them as distinct. “We wanted to determine if they can discriminate between familiar and unfamiliar calls that are played back as seismic signals,” O’Connell-Rodwell explains.<br> <br> Although still analyzing data from the experiment, O’Connell-Rodwell made some preliminary observations: “The data I’ve seen so far suggest that the elephants were responding like I had expected. When the ‘94 warning call was played back, they tended to clump together and leave the water hole sooner. But what’s really interesting is that the unfamiliar anti-predator call from Kenya also caused them to clump up, get nervous and aggressively rumble--but they didn’t necessarily leave. I didn’t think it was going to be that clear cut.”<br> <br> The findings could have implications for conservation, she said.<br> <br> Human-generated noise may be a menace to elephant lifestyles, she explained. Researchers have found that rotating helicopter blades generate low-pitched noises, and possibly seismic vibrations, that can disrupt and frighten wild herds located far away. David Larom and others argue, therefore, that the use of helicopters in areas inhabited by elephants should be carefully monitored and controlled.<br> <br> Seismic research also may prove useful as a deterrent against poachers. “There is military technology to detect and track tanks seismically,” said David Larom, an environmental scientist formerly with the University of California-San Diego and now in private industry. “This could potentially be used to track poacher vehicles as well.” <br> <br> Eventually, O’Connell-Rodwell hopes to broaden her research to include other large animals that produce low-frequency vocalizations, such as rhinos, lions and giraffes.</font></b></p> </body>