Ultrasound repellers could keep hedgehogs off roads, scientists hope

Study shows animals hear very high frequencies, making it possible to design a deterrent to cut deaths Patrick Barkham Wed 11 Mar 2026 07.00 CET Prefer the Guardian on Google

Hedgehogs have been discovered to hear high-frequency ultrasound, raising hopes that they could be deterred from dangerous roads with ultrasound repellers.

Vehicles are estimated to kill up to one in three hedgehogs, a big factor in the much-loved mammal’s drastic decline across Europe over recent decades.

Researchers at the University of Oxford collaborated with colleagues in Denmark to test the auditory brainstem response of 20 hedgehogs rehabilitated in Danish wildlife rescue centres. Small electrodes placed on the animals recorded electrical signals travelling between the inner ear and the brain, while short bursts of sounds were played through a loudspeaker.