Whale sonar. Artwork illustrating the sonar mechanism used by whales to detect their prey (such as squid, far right). Toothed whales, such as this Blainville's beaked whale, produce a variety of sounds by moving air between air-spaces or sinuses in the head. Sounds are reflected back from objects. These echoes are thought to be received by an oil-filled channel in the lower jaw, and conducted to the whale's middle ear.