Israeli jails are using computers to interpret the barks of guard dogs to warn of prison breakouts.

Noam Tavor, head of the Israeli Prisons Service canine unit, said the computer collects the dogs' barks through microphones, sorts and grades them. It tells the warders only about the barks that are significant in terms of security, the ones which show stress or aggression in the dog.

Prison staff monitor the system through loudspeakers and TV cameras that automatically zoom in on suspected hot spots. The system was designed by Bio-Sense and is installed in four Israeli prisons.