The European hedgehog (Erinaceus europaeus) is undergoing widespread decline across its native range, with road traffic and garden machinery recognised as major sources of mortality. Because hedgehogs are nocturnal and likely rely heavily on auditory cues while foraging and navigating, understanding their hearing capabilities is important both for behavioural ecology and for designing mitigation strategies that reduce harmful human–hedgehog encounters.We investigated the hearing sensitivity of European hedgehogs using auditory brainstem response (ABR) testing on rehabilitated individuals prior to release. Hearing thresholds were measured between 4 and 85 kHz, revealing that hedgehogs possess broad auditory sensitivity extending well into the ultrasonic range, with peak sensitivity around 40 kHz. This demonstrates that the species can detect frequencies far above those audible to humans and many domestic animals. However, this sensitivity also implies vulnerability to anthropogenic ultrasonic emissions. Ultrasonic pest deterrents, robotic lawn mowers, and automotive sensor systems commonly produce sound within the same frequency band, potentially disturbing or repelling hedgehogs. Our findings, therefore, highlight the need to consider acoustic environments in hedgehog conservation and provide a foundation for the development of targeted ultrasonic warning or repellent systems aimed at reducing road casualties and machinery-related harm.
Thomsen et al. (Thu,) studied this question.