HAMMERHEAD SHARK

any shark of the family Sphyrnidae (class Selachii). Hammerheads are widely distributed in all oceans, in warm and temperate waters. These sharks are named for the unusual shape of their heads, which are broad, flattened, and hammer- or spade-shaped, with the eyes and nostrils at the ends of the sidewise projections. It is thought that the peculiarly shaped head may serve as a rudder, aiding maneuverability, and that the nostrils, being widely spaced, enable better tracking of scents. Hammerheads are swift, powerful sharks that may be found at sea, close to shore, or in brackish water. They feed on fish, stingrays, skates, and other sharks. Some species are fished for leather and oil. Hammerheads have long been feared as potential man-eaters. Three species seem to be particularly dangerous: the great hammerhead (Sphyrna mokarran), growing to a maximum length of 4.5 m (15 feet) or more; the scalloped hammerhead (S. lewini), growing to about 3 m; and the smooth hammerhead (S. zygaena), growing to about 4.25 m. All three are grayish and are found throughout the tropics; the smooth hammerhead, which is valued as a sport fish, also ranges into cooler waters. These three species are individually distinguished by the shape of the front edge of the head: straight, with a central notch in the great hammerhead; curved outward with a central notch in the scalloped hammerhead; and curved outward but unnotched in the smooth hammerhead.