Seeing in the Dark
How can dolphin see in that dark water? Those of us who have to clean the bottom of our boats, know that you can hardly seen your hand in front of your face in these waters. Visibility in the Bull River is measured in inches, never feet. So how can dolphin find their food?
Nature has provided the toothed whales (unlike baleen whales) with a unique echolocation system. By making clicking sounds and listing for the echo, dolphin can make out the position and shape of objects around them. They can track movement, as well. This gives them a decided advantage over their prey, who can't see the dolphin until it is too late.
The sounds are not produced from their mouth or throat, but from their head! Specifically, from a fatty organ in their head, called a "melon". The sound waves can be focused in directional beams with a great deal of precision. The sound waves strike an object and the returning echo is picked up by an organ called an acoustic window, which is located in their jaw. The sound is then transmitted to their inner ear, then to their brain.