Hammerhead sharks are a type of shark named for the very distinctive shape of their heads, which look much like a hammer. This hammer shape is also called a cephalofoil. This cephalofoil serves a number of useful purposes for the shark including positioning its eyes like that of a bird to encompass a full 360° of vision. It also provides lift for the shark, helping to keep it at an appropriate depth. The cephalofoil also contains electroreceptors (which all sharks have) which help it find prey by detecting their electrical impulses through the water. Due to the wider spread of these receptors, hammerhead sharks can detect electrical signals down to one half of a billionth of a volt. Hammerhead sharks have significantly smaller mouths than other types of sharks, which predisposes them to be more of scavengers and predators of smaller fish. During the day, hammerhead have been known to form hunting schools in numbers greater than 100, and then dispersing at night to hunt by themselves.