hammerhead shark

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 Aggressive shark found in tropical marine waters and warmer temperate zones. It can be recognized by its head, which is extended sideways into two hammer-like lobes, with one eye and one nostril located at the tip of each. It is grey above and white below. Length: to 6.1m (20ft); weight: to 906kg (2000lb). Family Sphyrnidae.

Sphyrnidae (hammerhead shark; subclass Elasmobranchii, order Lamniformes) A small family of marine, occasionally brackish-water sharks characterized by the sideways expansion of the head with the eyes and nostrils located almost at the tip of the lateral expansions. These peculiar sharks are found principally in tropical coastal regions and tend to be large (e.g. Sphyrna zygaena grows to 7 m). There are about nine species.