Scientists have discovered that hedgehogs can hear ultrasound frequencies, a finding that could lead to new ways of protecting them from traffic.
Vehicles are believed to kill up to one in three hedgehogs, making road accidents one of the biggest threats to the declining populations of the European hedgehog across Europe.
Researchers now hope that specially designed ultrasound repellers could help keep hedgehogs away from busy roads.
Testing Hedgehog Hearing
The study was carried out by scientists from University of Oxford working with researchers in Denmark.
Twenty hedgehogs being rehabilitated at wildlife rescue centers were involved in the research.
To understand what the animals could hear, scientists measured the auditory brainstem response — the electrical signals traveling from the ear to the brain.
Small electrodes were placed on the hedgehogs while short sound bursts were played through speakers.
The results showed the animals responded to sounds ranging from 4 to 85 kilohertz (kHz).
For comparison:
- Humans hear up to 20 kHz
- Dogs hear up to about 45 kHz
- Hedgehogs can detect sounds well into the ultrasound range
The findings were published in the journal Biology Letters.
A Unique Ear Structure
Researchers also used high-resolution micro-CT scans to create a detailed 3D model of a hedgehog’s ear.
The scans revealed previously unknown features:
- extremely small, dense middle-ear bones
- a partially fused joint between the eardrum and the first bone
- a stiffer chain of bones that transmits high-frequency sounds efficiently
These characteristics are similar to those found in animals like bats that rely on ultrasound.
New Technology Could Prevent Road Deaths
The discovery opens the door to practical solutions for protecting hedgehogs.
Scientists believe that devices emitting high-frequency ultrasound signals could deter hedgehogs from dangerous areas such as:
- roads
- lawn mowers
- garden strimmers
Because hedgehogs detect much higher frequencies than many other animals, it may be possible to design devices that do not disturb pets like dogs.
A Hope for Hedgehog Conservation
Lead researcher Sophie Lund Rasmussen said the next step will be working with engineers and the automotive industry to develop practical deterrent systems.
If successful, these ultrasound devices could significantly reduce hedgehog deaths on roads — a major factor behind the species’ population decline.
For conservationists, the discovery is a promising step toward helping one of Europe’s most beloved animals survive in an increasingly human-dominated landscape. 🦔🚗