Platypuses use thousands of mechanoreceptors and electroreceptors in their bill skin to hunt prey in murky rivers and streams. Push-rod mechanoreceptors on the bill detect changes in pressure and motion, while two types of electroreceptors track the electrical signals produced by the muscular contractions of the small prey. Using a side-to-side motion of its head, the platypus gauges the direction and distance of its next meal by collecting, and combining, these flows of sensory information.

Source: American Museum of Natural History