Dolphins use sound so as to help them in hunting, navigating and communicating. They have the sensory ability used for locating food and for navigation underwater called echolocation. Sounds are reflected or echoed back from objects and these are thought to be received by an oil filled channel in the lower jaw and conducted to the middle ear of the animal. When swimming normally, the sounds emitted are generally low frequency. The echoes from these sounds provide information about the seafloor, the shorelines, underwater obstacles, water depth and the presence of other animals underwater.