A platypus will close its eyes, ears, and nose while hunting for food!
Monotremes are a classification of mammals, and are the only mammals, besides one species of dolphin, that have a sense of electrolocation.
The platypus for example, is a monotreme, and can use the hilarious looking bill on it's face to locate electric fields generated by muscular contractions. In fact, the platypus' electrolocation is the most sensitive of all the monotremes in the world!
Since the duckbill platypus is so sensitive to detecting electric fields generated by the muscular contractions of their pray, they actually close off all of their other senses!
They close their eyes, ears, and nose, because those senses are more of a distraction when hunting for prey!
The fact that the platypus can pick up electric signals helps distinguish between animate and inanimate objects while hunting! It can even tell how far away, and if their prey is moving just by using their bills!
We always thought that their bills just looked funny, and as it turns out, they actually DO something.