Nov 17

Species: Great hammerhead  (Sphyrna mokarran)

Great hammerhead (Sphyrna mokarran) photo

Great hammerhead (Sphyrna mokarran)

Status: Endangered (EN)

Interesting Fact: The great hammerhead can sometimes be cannibalistic, with larger adults preying on juveniles.

The great hammerhead is found in warm temperate and tropical waters around the world. During summer, these sharks migrate towards the poles in search of cooler waters. A true ocean predator, the great hammerhead preys on stingrays, groupers, small, bony fish, crabs, squid, other sharks and lobsters. Feeding mainly at dusk, the great hammerhead locates prey using an electro-sensory system which can sense the weak electric field produced by all living organisms.

Although not fully understood, the hammer is thought to help the shark scan larger areas of the ocean floor for food, and that it maximises the area of the sensory organs (known as the ampullae of Lorenzini) that can detect chemical, physical and thermal changes in the water, as well as electric fields.

The great hammerhead is threatened by overfishing. Its fins are used for shark fin soup, liver oil for vitamins, skin for leather, and its meat for fishmeal. Fortunately, the increasing recognition of these threats has led to the implementation of finning bans by fishing states in the U.S.A., Australia and the European Union. Bycatch limits for sharks in the South African longline fishery are also helping to conserve this endangered species.

Find out more about hammerhead sharks on the BBC Nature Website.

See videos and images of the great hammerhead on ARKive.

Lauren Pascoe, ARKive Researcher

  • Mike (November 28th, 2012 at 11:12 pm):