Sphyrna mokarran (Rüppell, 1837)

Great hammerhead shark

Species recognized by FishBase external link, R Froese & D Pauly (eds) in 
IUCN Red List Status: Endangered (EN) external link Showing: scientific names

Media Center Navigation

Sphyrna mokarran (Rüppell, 1837)

Images

Choose images

Sphyrna mokarran (Rüppell, 1837)
Sphyrna mokarran
Sphyrna mokarran (Rüppell, 1837)
Sphyrna mokarran (Rüppell, 1837)
Sphyrna mokarran (Rüppell, 1837)
Sphyrna mokarran (Rüppell, 1837)

Page navigation

Classification : Text | Graphic |
  

Table of Contents

Overview

Biology

Source and Additional Information
Supplier
ARKive external link
Copyright
Copyright Wildscreen 2003-2008. Some rights reserved external link
Location
Source URL
View original data object external link
Citation

The great hammerhead is particularly keen on feeding on stingrays, despite the danger of their barbs. The hammerhead pins down each ray with its hammer and then bites chunks from the wings until the ray is immobilised (4). It also feeds on groupers, sea catfish, small, bony fish, crabs, squid, other sharks and lobsters (2). It can be cannibalistic although it is not known what triggers this behaviour. Feeding mainly at dusk, the great hammerhead uses an electro-sensory system to locate prey; sensing the weak electric field produced by all living organisms. Larger sharks may prey on juvenile great hammerheads but adults have no natural predators (3). Mating has rarely been observed in this species, but unlike other sharks it is known to mate at the surface (3). Males use extensions of the pelvic fins called 'claspers' to transfer sperm to the female (5), resulting in a pregnancy lasting 11 months (3). Young are born live in the spring or summer (3). The function of the hammer is much discussed and a great many theories have been put forward as to its purpose. Amongst these theories, the most popular are that it helps the shark to 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 (5).
"Sphyrna mokarran (Rüppell, 1837)". Encyclopedia of Life, available from "http://www.eol.org/pages/224168". Accessed 20 Mar 2010.