But that sense has now been revealed to be more sophisticated, and more powerful, than anyone knew.
We’re all familiar with the change in pitch of a police or ambulance siren as the vehicle speeds past us.
New research from Rolf Mueller, professor of mechanical engineering in the College of Engineering, and his doctoral student, Xiaoyan Yin, shows that bats have been using that same phenomenon – a Doppler shift – to zero in on prey with incredible accuracy.
“The solution these two types of bats have come up with has been to tune in on the Doppler shifts that are produced by the wing beat motion of their prey,” Mueller explained. “These ‘good Doppler shifts’ serve as a unique identifying feature that sets prey apart from static distractors, such as leaves in foliage.”
The bats have even been shown to adjust the frequency of their own ‘sonar pings’ to account for the naturally-occurring Doppler shift caused by the speed of their own flight.
Mueller and Yin created models of the bats’ ears to demonstrate how this phenomenon worked, and correlated their work with high-resolution video of the bats’ hunting behaviour that prove beyond doubt that the bats have a “built-in ambulance” that makes them one of the deadliest night-time predators in the sky.
The research will help the next generation of engineers to build drones that can operate in dense foliage or autonomous underwater vehicles navigating near complex underwater structures.
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