At a time when man-elephant conflicts and crop raids are increasing every day across the country, this menace can be minimised by playing sounds of growling tigers and leopards to wild elephants on their way to human habitats or raid fields, says a study.
The study has been undertaken by Dr. Vivek Thuppil, an animal behaviour scientist and his colleague Dr.Richard G. Coss from the University of California,US. In an experiment of its kind the study looked at the nocturnal behaviour of elephants, and particularly their reaction to aggressive tiger and leopard growls, in villages bordering elephant habitats in the two states of Karnataka and Kerala.
“Prey species exhibit certain specific anti predator behaviours as alertness, aggression and flight, among others, in response to predators. The nature of this response is variable, with animals reacting more strongly in situations of increased vulnerability,” says the study.
As a part of this experiment, the researchers played back recorded growls of tigers and leopards when herd of wild elephants were in the vicinity of fields to raid crops. Infrared beam sensors to automatically trigger off the growls as elephants approached a crop field.
“We examined the provocative effects of elephant-triggered tiger and leopard growls while elephants attempted to crop-raid. Tigers opportunistically prey on elephant calves, whereas leopards pose no threat; therefore, we predicted that the elephant response would be reflective of this difference,” said Dr. Thuppil.
This behavioural difference was apparent, noted the study. While elephants retreated silently to tiger-growl playbacks, they responded with aggressive sounds as trumpets and grunts, to leopard-growl playbacks. Elephants also lingered in the area and displayed alert or investigative behaviours in response to leopard growls when compared with tiger growls.
Interpreting this difference, the researchers said that tigers are natural predators of elephant calves while leopards do not prey on elephants at all. Hence, this explained the difference in jumbo reactions to the growls.
On hearing tiger growls the elephants silently retreated and left. But leopard growls caused the elephants to trumpet loudly and even probe nearby bushes before finally going away.
Dr. Thuppil is confident that if tiger growl playbacks are deployed continuously during crop growing they could prevent elephants raiding fields.
However, other experts were not sure of the efficacy of the system. “The replays of predator calls have been tried in the past in the areas vulnerable to man-elephant conflicts, but the problem is elephants soon realize that it is a hoax,” said a WII scientist. The nocturnal behaviour of Indian elephants is poorly understood and needs to be studied further, he added.