Hearing like a herring

A sensor inspired by the way fish detect sound under water could allow the US Navy to develop compact arrays to detect enemy submarines.

These new arrays would detect quiet underwater targets, while also providing unambiguous directional information.

Using optical fibres, researchers at the Georgia Institute of Technology have found a way to create a sensor that detects the direction from which a sound is coming under water. This directional component is an important improvement over the current technology, researchers said.

‘Detecting quiet sounds under water can be very difficult,’ said Francois Guillot, a research engineer in Georgia Tech’s School of Mechanical Engineering. ‘But our sensor detects small sounds over the noise of the ocean and also provides directional information.’

The sensor uses a mechanism inspired by how fish hear under water. Inside a fish’s ear, there are thousands of tiny hairs that move when a sound wave passes through the fish. These hairs then communicate with nerves allowing fish to hear under water. Because fish excel at detecting sound so they don’t get eaten, the Georgia Tech researchers chose the fish hearing system as their model, they said.