An extraordinary insect preserved in amber is opening our ears to a world of communication beyond our hearing. New research on an extinct katydid in the Natural History Museum's collection reveals that katydids have been using ultrasounds for millions of years to try and avoid predators hearing them.

The song and hearing range of the cricket-like insect has been discovered tens of millions of years after its death.

After being trapped in amber for 44 million years, new scans of Eomortoniellus handlirschi have allowed scientists to reconstruct the katydid's mating call. It reveals the earliest known animal to communicate at frequencies far beyond the range of human hearing.

While not quite as high as some living katydids, its call's pitch would have been above the hearing of most mammals. Only a select group of mammals, including the first bats, were tuning into its call, as part of the opening salvos of an evolutionary arms race which continues today.