HAMMERHEAD SHARK






Nomadic hammerheads travel all of the world's oceans using sensory organs (ampullae of Lorenzini) on its head to locate meals. There are nine types of hammerhead: Scalloped hammerheads are among the three species dangerous to humans; the others are the 20-foot-long great hammerhead and the smooth hammerhead. Scallopeds can grow to about 14 feet, and often gather during the day in schools numbering in the hundreds. They feed primarily on rays, fish, squid, snails, small sharks and shrimp.


GENERAL DESCRIPTION The great hammerhead shark has a wide, thick head with the eyes at the margins. The head is indented at the center of the "hammer," which is almost rectangular in shape. This shark is gray-brown above with an off-white belly. The first dorsal fin (the large fin on the top of the shark that most people associate with sharks) is very large and pointed.


TEETH
Teeth are triangular with extremely serrated edges.


DIET AND FEEDING HABITS
The great hammerhead is a fierce predator with a good sense of smell that helps it find its prey. The great hammerhead eats fish, including rays, and other sharks, squid, octopuses, and crustaceans. The great hammerhead has been known to be cannibalistic.


HABITAT
The great hammerhead swims in warm and relatively warm water along the coastlines. They live over the continental shelves and the adjacent drop-off (the upper part of the mesopelagic zone) to depths of about 260 feet (80 m).
DISTRIBUTION The great hammerhead is found in tropical and sub-tropical waters worldwide.


MIGRATION
The great hammerhead migrates seasonally to cooler waters during the summer.


REPRODUCTION
The great hammerheads are viviparous, giving birth to live young. The 20-40 pups are about 27 inches (70 cm) long at birth.


HAMMERHEAD SHARK ATTACKS
Many of the hammerheads are harmless to people, but a few species, like the great hammerhead, can be very dangerous.