Gyrinus natator using concentric sonar waves, Dumfries House, East Ayrshire. Whirligigs use a form of sonar to detect food, objects, predators, other whirligigs, etc.
<a href="//commons.wikimedia.org/wiki/User:Rosser1954" title="User:Rosser1954">Rosser1954</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>