Whistle back if you understand: prize for team decoding what dolphins are saying

A prize for communicating with animals has been scooped by researchers who have shed light on the meaning of dolphins' whistles.

- Nicola Davis

The Coller Dolittle challenge for interspecies two-way communication was launched last year and comes with a $100,000 (£75,000) prize. The winning team, led by Laela Sayigh and Peter Tyack from the Woods Hole Oceanographic Institution, have been studying bottle-nosed dolphins in waters near Sarasota, Florida, for more than four decades.

The researchers used non-invasive technologies such as hydrophones and digital acoustic tags attached by suction cups to record the sounds made by the animals. These include name-like "signature" whistles, as well as "non-signature" whistles - sounds that make up about 50% of the animals' calls but are poorly understood.

In their latest work, which has not yet been peer-reviewed, the team identified at least 20 types of non-signature whistle that are produced by dolphins, finding two types were each shared by at least 25 individuals.

When the researchers played these two sounds back to dolphins, they found one triggered avoidance in the animals, suggesting it could be an alarm signal, while the other triggered a range of responses, suggesting it could be a sound made by dolphins when they encounter something unexpected.