Nature
PUBLISHED
With elephant populations in drastic decline in most of their range it is not surprising humans are not their favorite creatures. It turns out they have a call that means “human” and judging by the reaction it may actually mean “nasty humans coming, run”.
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Dr Lucy King of Oxford University recorded the voices of Samburu people from North Kenya and played them to resting elephants. She reports in PLOS ONE that the elephants came to attention and ran around trumpeting and emitting a low rumble.
Moreover, when King recorded this rumble (which sounds rather like the mood noises at the danger point of a science fiction film) and played it to a different group of elephants they reacted the same way. Differences in the rumble reflect the intensity of the danger, and attract proportional responses
So far the findings were not surprising. King showed in 2007 that elephants reacted similarly to the sound of disturbed bees, whose sting can be damaging around the eyes, trunk and behind the ears, or to newborn elephants. However, she has now revealed this was not a common “danger” call, such as many social animals are known to use.
The rumble in response to humans was acoustically different to that responding to bees. “Elephants appear to be able to manipulate their vocal tract (mouth, tongue, trunk and so on) to shape the sounds of their rumbles to make different alarm calls,” says King. The difference between the bee and human sound was like the variation in human words with the same consonants but different vowels. The paper notes that elephants have been shown “to exhibit vocal flexibility and vocal learning, by vocally imitating environmental sounds and the vocalizations of other species, including different elephant species and humans.”
The bee rumble prompted elephants to shake their heads, presumably to dislodge bees, which they did not do on getting word of humans.
“We concede the possibility that these alarm calls are simply a by-product of elephants running away, that is, just an emotional response to the threat that other elephants pick up on,” Lucy told phys.org, “On the other hand, we think it is also possible that the rumble alarms are akin to words in human language, and that elephants voluntarily and purposefully make those alarm calls to warn others about specific threats. Our research results here show that African elephant alarm calls can differentiate between two types of threat and reflect the level of urgency of that threat.”
Bees have been used as a sort of barrier to reduce conflict between humans and elephants, with beehives preventing elephants from straying into villages, while the farmers gain the additional benefit of honey. However, King has shown that where establishing hives is not appropriate, sound recordings can be used instead.
“Learning more about how elephants react to threats such as bees and humans will help us design strategies to reduce human-elephant conflict and protect people and elephants,” says King.
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