Great Hammerhead shark (Sphyrna mokarran)
Order: Carcharhiniformes, Family: Sphyrnidae
Hammerheads are best known for their distinctive mallet-shaped heads and widely spaced eyes, which they swing back and forth while swimming to detect prey. They are the only species of shark known to travel in schools.
I. GEOGRAPHIC RANGE
- Oceanic Islands, Atlantic Ocean, Pacific Ocean, Indian Ocean: Great hammerhead sharks occur in all tropical waters worldwide.
II. PHYSICAL CHARACTERISTICS
- Mass: 400 to 460 kg.
- 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.
III. FOOD HABITS
- Great hammerhead sharks feed on rays, smaller sharks, and many species of bony fishes.
- 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.
- Little is known about behavior or social systems of great hammerhead sharks. Unlike scalloped hammerhead sharks, they are solitary hunters and dangerous to humans.
- These sharks are found in both open ocean and shallow coastal waters. During summer they may make small migrations towards more northerly areas.
- Biomes: reef, temperate coastal, tropical coastal
VII. ECONOMIC IMPORTANCE FOR HUMANS
Great hammerhead sharks are classified as game fish, as are all large hammerhead sharks. Their skin is often used for leather.
These sharks are potentially dangerous to humans and cases of attacks by great hammerhead sharks have been documented.
- Status: No special status
- Great hammerhead shark populations seem to be stable.