This stamp issue celebrates the wonder of sharks with a pane of 20 stamps, featuring realistic images of five species that inhabit American waters:
•    The mako shark, represented here by a short-finned mako (Isurus oxyrinchus)
•    The whale shark (Rhincodon typus)
•    The thresher shark, here a pelagic thresher (Alopias pelagicus)
•    The hammerhead shark, this one a scalloped hammerhead (Sphyrna lewini)
•    The great white shark (Carcharodon carcharias)

Great Hammerhead is one of the sharks which has a nictitating membrane. The Great Hammerhead can be up to 20 ft. long and weigh more than 990 pounds. Most Great Hammerheads are between 11 ft. and 15 ft. long. The Great Hammerhead can be very dangerous to humans, BUT unprovoked attacks are very seldom seen.

Great Hammerheads are very characteristic with a remarkable shaped head, which are shaped like a hammer, where the eyes are at the end of the "hammer". The Great Hammerhead's hammer is very straight and filled with ampullae of Lorenzini (small electric sensors) which are used like a sort of radar that are used to search for fish that have dug themselves into the sand on the ocean bed.

The Great Hammerhead, which are a very common species of sharks, is greyish brown with a light belly and the shark has an extreme tall and sharp first dorsal fin that curves backwards. There are 9 species of Hammerhead Sharks, and they live a long way from shore and on depth down to 300 yd. Young Hammerheads can go near the shore. The Hammerhead Shark can be found in the tropical and subtropical waters from 40 degree north to 40 degree south.

Great Hammerheads feed on different species of fish and other sharks and rays. The Great Hammerhead can eat the poisonous Stingray, because the shark do not get bothered by it poisonous sting. In one case several hundred stings had been found in a Great Hammerhead.

The Great Hammerhead is sexually mature, when it reaches a length of about 10 ft. The Great Hammerhead is pregnant for seven month and gives birth to live young ones. They can get up to 42 young ones in every litter and the young ones are up to 28 in.

At daytime the Great Hammerhead lives in large schools with several hundred animals, but some think that these schools can contain more than a thousand animals, but this have not been confirmed. At night time the schools of sharks spilt up to hunt, the next day they will be in schools again.

Some divers have succeeded in swimming with a Great Hammerhead, and being drawn by the shark. The divers hold on to the shark's dorsal fin or its tail, but this cannot be recommended, because a shark might get provoked by the contact so an attack will not be unprovoked anymore.