Asian elephants are scared of tigers and retreat when they hear the sound of the feline's growl. This new finding could mean another strategy for keeping crop-raiding elephants away from farmers' fields in India.
Elephants are a significant problem for farmers, often injuring or killing people in addition to destroying crops. And of course the killing goes the other way, with about 100 elephants a year being killed by poisoning or electrocution, as farmers try to protect their fields.
Vivek Thuppil and Richard Coss of University of California, Davis, published their findings this month in Biology Letters on a new tool that could work to keep elephants away. Similar to the recordings of bee hives that keep African elephants out of fields, playing recordings of tiger growls can make Asian elephants back off.Science Daily reports, "The researchers set up equipment to play back leopard or tiger growls triggered when the elephants crossed infrared beams across paths leading to crop fields, and captured the events on video... Although their initial reactions were very different, the elephants ultimately retreated from growls of both cats."
"When Thuppil and Coss played tiger growls from their hidden speakers, elephants immediately backed away, slowly and quietly," writes National Geographic. "If they played leopard growls, they trumpeted and grunted, investigated the surrounding area, searched for sounds and smells, and kicked the dirt. Only then did they walk away. Their reactions are prudent. Tigers are the greater threat, since they’ll occasionally kill elephant calves."
Here is an elephant running away, then trumpeting, at the sound of the recorded growls:
And another herd that picks up the pace running away from the recording:
The recordings work well... for awhile. The research showed however that elephants can eventually habituate to the sound, knowing there isn't a real threat. Just as with dealing with any intelligent animal -- as rangers keeping bears out of campsites or ranchers keeping coyotes away from sheep can testify -- novelty is an important part of deterring them. The researchers are coming up with ideas, such as a playback system that changes the location of the sound as the elephant moves, simulating a predator that is on the move as well.
While it's good news to conservationists that wild elephant populations are stable or growing in forested areas, it is not good news to the people living at the fringes of those forests and must deal with the impacts of herds of massive animals passing through. Finding effective, nonlethal tactics like these recordings could minimize negative interactions between elephants and people, protecting both from each other. And that is good news to everyone.