By Robin Street
Geographic Range
Great hammerhead sharks occur in all tropical waters worldwide.
Biogeographic Regions:
oceanic islands 
(native ); indian ocean (native ); atlantic ocean (native ); pacific ocean (native ).
Habitat
These sharks are found in both open ocean and shallow coastal waters. During summer they may make small migrations towards more northerly areas.
Physical Description
(880 to 1012 lbs; avg. 946 lbs)
Great hammerhead sharks posses a virtually straight anterior margin of the head with a deep central indentation. They have high second dorsal fins and the pelvic fins have curved rear margins. The teeth are triangular with extraordinarily serrated edges, becoming increasingly oblique toward the corners of the mouth. Their coloration varies from deep olive green to brownish grey above and white below. They are generally 4 to 6 m in length.
Some key physical features:
bilateral symmetry .
Reproduction
Great Hammerhead sharks are viviparous. At a length of 3m, maturity is reached. Litters are made up of between 20 and 40 pups. Young are born in the summer season and are approximately 70 cm in length. Head shape of a newborn pup is more rounded than that of an adult but this changes as they grow.
Behavior
Little is known about behavior or social systems of great hammerhead sharks. Unlike scalloped hammerhead sharks, they are solitary hunters and dangerous to humans.
Key behaviors:
natatorial ; motile .
Food Habits
Great hammerhead sharks feed on rays, smaller sharks, and many species of bony fishes.
Economic Importance for Humans: Negative
These sharks are potentially dangerous to humans and cases of attacks by great hammerhead sharks have been documented.
Economic Importance for Humans: Positive
Great hammerhead sharks are classified as game fish, as are all large hammerhead sharks. Their skin is often used for leather.
Conservation Status
IUCN Red List: [link]:
Endangered.
US Federal List: [link]:
No special status.
CITES: [link]:
No special status.
Great hammerhead shark populations seem to be stable.
For More Information
Find Sphyrna mokarran information at
Contributors
Robin Street (author), University of Michigan.
