hammerhead shark (redirected from Sphyrnidae)

hammerhead shark, active, surface-living shark, genus Sphyrina. Its curious head has lateral projections resembling the crossbar of a T, and its eyes and ears are located in the outer tips of the projections. It has been suggested that the extension of the head in the plane of the pectoral fins may give the fish increased lift, but there is no evidence that hammerheads are better swimmers than other sharks. Found in inshore, brackish water, hammerheads are both predators and scavengers. They feed on a variety of fishes including skates, rays, and other hammerheads, and large hammerheads have been known to attack and eat humans without provocation. The largest species is the widely distributed great hammerhead, Sphyrina mokarran, which typically reaches 15 ft (4.6 m) in length; the distance between its eyes may be as much as 3 ft (90 cm). The common hammerhead, S. zygaena, is found in all tropical waters, summering as far N as Newfoundland. It may reach a length of 12 ft (3.7 m). The bonnet, or shovelhead, shark is a small, harmless hammerhead found in the W Atlantic from Brazil to Massachusetts. It reaches a length of 5 ft (150 cm) and its lateral lobes are much shorter than in other species, giving the head a rounded appearance. There are several other species distributed throughout tropical and temperate oceans. Hammerhead sharks are classified in the phylum Chordata, subphylum Vertebrata, class Chondrichthyes, order Selachii, family Sphyrnidae.

---

hammerhead shark

Any of the swift, powerful sharks in the family Sphyrnidae, having a broad, flattened, hammer- or spade-shaped head, with the eyes and nostrils at the ends of the sidewise projections. Widely distributed in all oceans, in warm and temperate waters, they feed on fish, stingrays, skates, and other sharks. Some species are fished for leather and oil. Three species seem to be particularly dangerous to humans: the great hammerhead (the largest hammerhead, growing to 15 ft, or 4.5 m, or more), the scalloped hammerhead, and the smooth hammerhead. All three are grayish and found throughout the tropics.