Populations of hedgehogs are rapidly shrinking across Europe. Can ultrasonic signals warn hedgehogs away from approaching vehicles or keep them clear of dangerous machines? One researcher is exploring ultrasound as an option to help save these tiny critters. Read more in @TheConversationUK https://theconversation.com/hedgehogs-can-hear-high-frequency-ultrasound-that-knowledge-could-help-save-them-275255