Like bats, dolphins use echolocation to navigate and hunt, bouncing high-pitched sounds off of objects, and listening for the echoes.
Echolocation is a technique used by bats, dolphins and other animals to determine the location of objects using reflected sound. This allows the animals to move around in pitch darkness, so they can navigate, hunt, identify friends and enemies, and avoid obstacles.
For dolphins and toothed whales, this technique enables them to see in muddy waters or dark ocean depths, and may even have evolved so that they can chase squid and other deep-diving species.
Source: discoverwildlife.com
