Hedgehogs Can Hear Far Beyond Human Range — And It Could Save Their Lives
Scientists have uncovered the remarkable hearing range of hedgehogs, revealing they can detect sounds up to 85kHz — far beyond what humans, dogs, or cats can hear.
Hedgehogs May Be Talking — We Just Can't Hear Them
For years, we assumed hedgehogs communicated through a repertoire of snuffles, grunts, and snorts. But groundbreaking new research suggests these spiny creatures may have a far richer acoustic world than we ever imagined — one that operates entirely beyond the limits of human hearing.
Scientists have formally measured the hearing range of the European hedgehog for the first time, and the results have surprised even the researchers behind the study.
What the Research Found
Led by Dr. Sophie Rasmussen at the University of Oxford, the research team collaborated with bio-acousticians — specialists who measure hearing in animals — to design a series of audio pulses and tones. These were played to anaesthetised hedgehogs sourced from a local rescue centre, while researchers monitored the animals' brain activity to determine exactly which sound frequencies they could detect.
The findings were striking. Hedgehogs can hear sounds up to 85kHz — well into the ultrasonic range. To put that in perspective:
- Humans hear up to 20kHz
- Dogs hear up to 45kHz
- Cats hear up to 65kHz
Anything above 20kHz is classified as ultrasound, meaning hedgehogs are operating in an acoustic realm completely inaudible to us.
The Secret Is in the Ear Structure
To understand how hedgehogs achieve this, the team constructed a detailed 3D model of a hedgehog's ear. They discovered it contains a rigid chain of small bones that efficiently conducts high-frequency sounds — a mechanism strikingly similar to that found in echolocating bats.
This structural adaptation allows hedgehogs to pick up ultra-high-pitched signals with remarkable clarity, hinting that the animals may be exchanging information through sounds we have never been able to detect.
Why This Discovery Matters for Conservation
The European hedgehog is classified as near-threatened by the International Union for Conservation of Nature, and populations across the UK and Europe have been declining steadily. Thousands are killed on roads each year, many by cars, lawnmowers, and garden strimmers.
Dr. Rasmussen believes this discovery could be a genuine game-changer for hedgehog conservation. With a precise understanding of their hearing range, scientists and engineers may now be able to develop targeted ultrasonic repellents — devices that emit sounds hedgehogs find alarming, deterring them from dangerous areas without disturbing humans or domestic pets.
"It's amazing because this allows us to actually build targeted sound repellents that wouldn't bother us or our pets," said Rasmussen.
Interestingly, some vehicles already use ultrasonic whistles to deter large animals such as deer. The Society of Motor Manufacturers and Traders (SMMT) confirmed such devices are widely available to consumers, though Chief Executive Mike Hawes noted that further research is needed to verify their specific effectiveness for hedgehogs.
Protecting Hedgehogs in Rescue Centres
Beyond road safety, the research has important implications for the thousands of hedgehogs taken into rescue centres across the UK each year. These facilities may unknowingly expose animals to distressing sounds — such as the high-frequency hum of machinery — that humans cannot perceive but hedgehogs can hear clearly.
Understanding their hearing sensitivity could allow rescue centres to create quieter, less stressful environments for recovering animals.
Are Hedgehogs Secretly Chatty?
Perhaps the most intriguing implication of the study is the possibility that hedgehogs are far more communicative than we realised. Observers have long noticed that hedgehogs appear to interact when they encounter one another — but assumed this was driven by scent rather than sound.
Dr. Rasmussen isn't so sure. "When hedgehogs pass by each other, you can tell that they are interacting. Maybe that's just chemical reactions to smelling each other," she said. "But imagine that they're actually blabbering all the time and we just couldn't hear it."
Further research is now needed to identify which specific sounds trigger a response in hedgehogs — whether sharp, sudden noises or rhythmic pulsating tones prove more effective as deterrents. Researchers are also keen to ensure that any sound-based devices do not discourage hedgehogs from frequenting gardens, which have become a critical habitat as rural landscapes grow increasingly inhospitable.
The full study has been published in the journal Biology Letters.
