Rats equipped with radios that transmit their brainwaves could soon be helping to locate earthquake survivors buried in the wreckage of collapsed buildings.

Rats have an exquisitely sensitive sense of smell and can crawl just about anywhere. This combination makes them ideal candidates for sniffing out buried survivors. For that, the animals need to be taught to home in on people, and they must also signal their position to rescuers on the surface.

In a project funded by DARPA, the Pentagon�s research arm, Linda and Ray Hermer-Vazquez of the University of Florida in Gainesville have worked out a way to achieve this.