Recordings of growling tigers have proved effective in scaring off elephants from their crop-destroying incursions into Indian villages, researchers say. Widespread use of the technique may lead to the saving of lives and crops, they said, as hundreds of deaths and significant crop losses have occurred in the last decade in regions where elephants come into contact with people. Writing in the journal Biology Letters, the scientists report a study of the nighttime behavior of elephants and their reaction to the playback of \"aggressive\" tiger and leopard growls in villages bordering two animal reserves in the Indian states of Karnataka and Kerala. Infrared beams were set up on paths elephants use as routes to crops, and when the beams were broken by the elephants they triggered a playback of a recording of either tiger or leopard growls, the researchers said. The system was set up to operate without human intervention for safety reasons, they said. \"Studying elephant behavior at night is extremely risky,\" lead author Vivek Thuppil, an animal behaviorist at the University of California, Davis, told SciDev.net. Some experts were skeptical that the technique could remain effective over time. \"Many such experiments on predator call replay have been tried on elephants, but the primary drawback is that elephants ultimately realize the hoax,\" Sushant Chowdhury of the Wildlife Institute of India said.