These clicks are sent out thro ugh the bump or melon on the dolphin's head. They hit objects and bounce back or echo. The echoes return to the dolphin where they appear to be picked up by the jaw and carried to its ears. The time the echo takes to return tells the dolphin the distance. Changes in the quality of the sound give information on how large and hard an object is.
Echolocation allows dolphins to find things without using sight.
Dolphins may also use rocks and other bottom structures to navigate with sound. Humans in ships and submarines use sonar in much the same way. Threats To Dolphins Tooth marks on dead dolphins show that sharks attack dolphins. Killer whales also eat dolphins. During unusually cold weather, dolphins may also suffer, especially if it occurs earlier than normal.