How do you make an elephant vanish?

Farmers sometimes kill elephants for raiding their crops. Rampaging elephants have also killed people, and they are then hunted down by park rangers.

The discovery that elephants emit low-frequency alarm calls around bees could help lessen these conflicts, said Lucy King, an animal behavior researcher whose paper on the calls was published in a journal of the Public Library of Science last week.

Farmers could make “bee fences’’ by stringing up hives on poles about 10 yards apart, King said. A strong wire connecting the poles would cause them to swing if an elephant walked into it, disturbing the bees. The swarm would bother elephants so much that they would flee, emitting low rumblings inaudible to the human ear to warn other elephants.

“It’s impossible to cover Africa in electric fences,’’ King said. “The infrastructure doesn’t exist in many places and it would restrict animals’ movement. This could be a better way to direct elephants away from farmers’ crops.’’

King’s findings are based on two separate experiments, part of a project by Oxford University and Save the Elephants. In the first, she played recorded bee sounds near elephants, causing them to flee. The researchers noticed that elephants distant from the sound also moved away, leading them to speculate the elephants were communicating an alarm below the range of human hearing.

For her second experiment, King hung ultrasensitive microphones from trees. She recorded elephant rumblings over a two-month experiment in Kenya’s Samburu park.

She then played the sounds back to elephants. When they heard the recordings they moved away, confirming the researchers’ hunch about alarm calls.

King said further research is needed before her findings can be put to wide use. But she is hopeful they can help find a solution to some of the 1,300 complaints the Kenya Wildlife Service records about elephant-human contact each year. Many elephants in Africa don’t live in the protected confines of a national park.

The findings have generated some excitement.

“This sort of initiative is very encouraging in helping prevent human wildlife conflict,’’ said Paul Udoto, a spokesman for KWS.