hammerhead shark


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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. This arrangement apparently gives the shark excellent binocular vision, and helps them see above, below, and behind as well as in front. 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 ChordataChordata
, phylum of animals having a notochord, or dorsal stiffening rod, as the chief internal skeletal support at some stage of their development. Most chordates are vertebrates (animals with backbones), but the phylum also includes some small marine invertebrate animals.
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, subphylum Vertebrata, class Chondrichthyes, order Selachii, family Sphyrnidae.
References in periodicals archive ?
AA Yaptinchay of the Marine Wildlife Watch of the Philippines expressed dismay over the killing of the hammerhead shark.
The Fisheries Regulation 2008 has been amended to help support a conservation dependent listing which would allow continued take of the hammerhead shark.
The smooth hammerhead shark was easily identified by the following key diagnostic features: head arched with four notches and without a median indentation; first dorsal fin moderately high, with second dorsal and pelvic fins low; pelvic fins not falcate; and lower caudal fin lobe without a dark blotch on it.
It stated the whale shark and widehead hammerhead shark populations were being rapidly put at risk due to overfishing.
According to the landing data, Dog shark was found to be the most dominant species followed by Hammerhead shark in terms of yield in both Chittagong and Cox's Bazar.
The list above includes animals like marine turtles that people might think are "cute," as well as animals like hammerhead sharks that people might think are scary.
The determinants of sexual segregation in the scalloped hammerhead shark, Sphyrnalewini.
Number sampled of the scalloped hammerhead shark Sphyrna lewlnl taken from 2004-2006 off south-west Mexico.
The great hammerhead shark (Sphyrna mokarran) is a large (maximum size of 550-610 cm total length [TL]) cosmopolitan species found circumtropically in both inshore and oceanic habitats to depths of over 80 meters (Compagno, 1984).
The United States had said it will seek a second chance to gain protection for the distinctive scalloped hammerhead shark, denied so-called Appendix II status by a handful of votes earlier in the week.
The scalloped hammerhead shark Sphyrna lewini, is a species for which these data are currently lacking, though urgently needed given its globally endangered status on the IUCN Red List.