Female elephants ready to mate call out for any nearby suitors, the low frequency sounds travelling through the air, but also seismically through the ground
WHEN LOVE is in the air elephants can literally make the earth move. Females ready to mate call out for any nearby suitors, the low frequency sounds travelling through the air, but also seismically through the ground.
Receptive males can pick up the invitation from up to six kilometres away, and probably much farther if “heard” through the ground stated Dr Caitlin O’Connell-Rodwell of Stanford University, who yesterday spoke at an American Association for the Advancement of Science session entitled Smooth Animal Operators.
The session was perfectly timed to St Valentine’s Day, given that basically it looked at how animals “pull”. It included speakers who described how male birds dance and display to impress females, how animal faeces is being analysed to measure levels of stress and sex hormones, and of course, how interested elephants can stay in touch when tonight is the night.
Dr O’Connell-Rodwell discovered this unexpected underground communications system while observing wild elephants at the Etoshia National Park in northern Namibia 14 years ago.
She has conducted extensive analysis since, discovering along the way how they accomplish the feat which involves listening through their feet.
She found that the animals could pick up the sound waves travelling through the ground via their feet. The impulses travel up the leg bones and on into the ear and can be sensed by the elephants despite the sound being very weak.
Her early studies suggested that a listening elephant could distinguish who was sending the call, an elephantine form of “caller ID” she observed.
Dr O’Connell-Rodwell’s latest work relates to the far more serious business of finding your mate and finding her as quickly as possible when the time is right.
Females emit an “oestrus call”, a low frequency sound that can travel through air but also through the ground. They are slightly higher pitched, but continue for longer than ordinary calls.
“It sounds like a truck changing gears in the distance,” Dr O’Connell-Rodwell suggested. “I have never seen males calling back. They are more interested in listening and in finding her.” Hardly a surprise!
Trials run with 27 bull elephants in groups of nine, including adults in “must”, adults out of “must” and sub-adults, showed that 75 to 80 per cent of the “must” adults and sub-adults answered the call immediately, the juveniles tagging along after the responding “must” males.
This ability has significant importance in continuing the species, Dr O’Connell-Rodwell pointed out. Being in oestrus is a rare event and might only happen every few years.
She now also believes that it could be used to attract marauding bulls in “must” back onto reserves.
Anxious males trying to respond to an oestrus call often crash out of the reserves only to wreck valuable water supplies and tear up scarce crops.
Emitting a false female love call might serve to get the errant male back into the park and out of harm’s way, she suggested.