Bats, Marine Mammals
In the animal kingdom, echolocation is an animal's determination of the position of an object by the interpretation of echoes of sounds produced by the animal. Echolocation is an elegant evolutionary adaptation to a low-light niche. The only animals that have come to exploit this unique sense ability are mammals—bats, dolphins, porpoises, and toothed whales. It is now believed that these animals use sound to "see" objects in equal or greater detail than humans can see with reflected light.
Echolocation is an adaptation to night life or to life in dark, cloudy waters. Long ago, bats that ate insects during the day might have been defeated in the struggle for survival by birds, which are agile and extremely sharp-sighted insectivores. Similarly, toothed whales, porpoises, and dolphins might have been quickly driven to extinction by sharks, which have a very keen sense of smell. These marine mammals not only compete with sharks for food sources, but have themselves been preyed upon by sharks. Echolocation helps them find food and escape from predators.