Dolphins send out either clicking sounds or whistles, all the time. Their clicking sounds, like the bat’s sounds, are also short pulses and also have a high frequency. The dolphins make the sound from an opening just below their blowhole. Also like the bat’s sounds, the dolphin’s clicking sounds, are mainly made by the dolphin to find the location of objects by echolocation. The opening that dolphins use to make their noises is called the oily melon. This oily melon resounds the pulses that the dolphin makes so that the dolphin can receive echoes of the pulses from a bigger range. Echoes are received by the dolphin near the lower jaw and are then conveyed to the middle ear. The dolphin also instinctively examines the echoes to find out about objects of interest, such as: walls (so they won’t run into them), other big sea animals (so they can avoid them), and other dolphins (so they don’t collide with them). A dolphin can also identify smaller animals such as fish and shrimp, which make up most of their daily diet. The whistles that dolphins send out aren’t related to echolocation, but are also interesting. Because water is denser than air, sound waves travel faster in water. Animals that use echolocation underwater will be able to judge the angle of an object faster than animals that use echolocation in air, providing that they are the same distance away from the object.