Hammerhead Shark / Sphyrna zygaena

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.

SIZE
The average great hammerhead shark is up to 11.5 feet (3.5 m) long. The largest reported was 20 feet (6 m) long. These large sharks average about over 500 pounds (230 kg) but can weigh as much as 1,000 pounds (450 kg).

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.

Stingrays seem to be a particular favorite of the great hammerhead. It kills the ray by using its "hammer" to pin the stingray down while it takes bites from the ray's wings.

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

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.

Photography: Gordo Banks / San Jose del Cabo / Alberto Misrachi