Réponses pour [Forecast Q2-2025] - Mystery of Elephant Communication

A 1O'Connel-Rodwell, a postdoctoral fellow from Stanford University, came to Namibia's foremost wildlife sanctuary, Etosha, to find out more about the little-known subject of elephant communication. Almost 20 years ago, researchers, including  O'Connel-Rodwell made the surprising discovery that elephants communicate over long distances using extremely low-frequency sounds, also called infrasound, which are generally too deep to be heard by humans.

B It is possible to find some clues to the elephant's ability to hear infrasound within the structure of the ear itself. 7The hammer bone of the elephant's inner ear is proportionally very large, which is typical for other animals that use vibrational signals. Additionally, the elephant and its relative, the manatees, are unusual among mammals for having a cochlear structure in the inner ear which is similar to that of many reptiles. In reptiles, this cochlear structure facilitates keen sensitivity to vibrations, and the same seems to be indicated in elephants.

C There are other indications in the elephant's anatomy to support their ability to hear infrasound. 2Firstly, the sheer size of their bodies allows them to generate low-frequency sounds which can be almost as powerful as a jet take-off. Their large bodies also provide ideal 'frames' for receiving vibrations through the ground and up to their heads. Secondly, their toe bones rest on fatty pads which may help to focus vibrations from the ground into the bone. 8Thirdly, the way the elephant brain lies within the cranial cavity, behind the eyes and in line with the auditory canal, may help them feel the vibrations. 9The front of the skull has many sinus cavities which might function as resonating chambers for receiving the vibrations from the ground.

D O'Connel-Rodwell’s background reveals the reason why she was the one to realize that elephants used seismic communication. “I did my master's thesis on seismic communication in planthoppers, ”she wrote. 10“I'd put a male planthopper on a stem and play back a female call, and the male would do the same thing the elephants were doing：He would freeze, then press down on his legs, go forward a little bit, then freeze again. It was just so fascinating to me, and it's what got me to think, maybe there's something else going on other than acoustic communication. 3”It was already known that seismic communication is common in a number of small animals such as spiders, scorpions, frogs, blind mole rats, kangaroo rats, elephant seals and golden moles, but O'Connell-Rodwell was the first to realize that such a large mammal could also use the method.

E Further research has shown that this ability to communicate over long distances is actually essential to the survival of the species. For example, if a predator is detected in the area, experienced members of the herd emit intense warning calls which prompt the herd members to come together for safety and then leave the area. 4In 1994, O'Connell-Rodwell recorded the warning sounds of a breeding herd being threatened by lions at Mushara. “The elephants got really scared, and the matriarch, the oldest and largest female cow, made these very powerful warning calls, and then the herd took off screaming and trumpeting, ”she recalls, 12“Since then，every time we played that particular call at the water hole, we get the same response-the elephants take off. ”

F In this case, the warning sounds are transmitted through the air, so researchers wanted to find out more about whether elephants could detect calls transmitted through the ground. In 2002，they devised an experiment using electronic equipment that allowed them to send signals through the ground. 5“The results of our 2002 study showed us that elephants do indeed detect warning calls played through the ground, ”O'Connell-Rodwell observed. “We expected them to clump up into tight groups and leave the areas, and that's in fact what they did. But since we only played back one type of call, we coudn't really say whether they were interpreting it correctly.” Clearly, further study was needed as the elephants may interpret the sound as something strange.

G 6Another experiment in the same area in 2004 was aimed at further studying elephants' sound-detecting abilities by using three different recordings-the 1994 warning call from Mushara, an anti-predator call recorded by scientist Joyce Poole in Kenya, and an artificial warble tone. The recordings were played at random and at various times to see if the elephants would recognize them as distinct vibrations.  11O'Connel-Rodwell explained that the aim was to determine whether they can discriminate between familiar and unfamiliar calls that are played back as seismic signals. Even though the analysis phase of the research data from the 2004 experiment is still under way, O'Connell-Rodwell is able to make a few preliminary observations and conclude that the reactions of the elephants were exactly as expected. 13“When the 1994 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. ”