Dolphins use clicking sounds and echoes to locate fish and navigate in murky water.

The longer version

Clicks leave the rounded forehead as a narrow beam, and echoes return from anything denser than the surrounding water. Distance is judged from the delay, while shape and texture come from how the returning pattern is stretched or altered. Fatty tissue in the lower jaw conducts incoming vibrations toward the ear.

The brain assembles a rapid acoustic picture that works well where visibility is poor. Click rate climbs as the animal closes in, ending in a buzz near contact. Signals differ between species, letting the listener separate prey, relatives and rivals in the same patch of water.

Where this entry sits

Oceans and Sea Life looks at the salt water that covers most of the planet, from crashing waves and tides to the darkest deep-sea trenches. Expect notes on coral, fish, whales, sharks, jellyfish, shells, and the strange creatures that live far below the surface. The full list sits on the Oceans and Sea Life page, where every entry is listed in order.