Sharks in Western Australia swimming close to popular beaches are using Twitter to send warning messages to surfers and swimmers.
The unique project means beach goers can make an informed decision about whether to go in the water knowing a shark is nearby.
Scientists have attached transmitters to more than 320 sharks, including great whites, which monitor their movements up and down the coast.
When a tagged shark swims within about a half mile of a beach, it triggers an alert which is picked up by computer. That computer then instantly turns the shark's signal into a short message on Surf Life Saving Western Australia's Twitter feed.