|The Great hammerhead shark is the largest member of the Sphyrna genus, and the largest hammerhead shark.|
|Map of were Sphyrna live (in blue)|
Sphyrna is one of the two genera in the Hammerhead shark group, and is the largest genera out of the two, with eight members in it. The word Sphyrna is a Greek word meaning "hammer", which refers to the shape of the shark's head.
Members in the Sphyrna group measure in size from the Scoophead, which is 100 centimeters (1 meters) long, to the Great hammerhead shark, which is 610 centimeters (6.1 meters) long. The Smalleye Hammerhead Shark weighs around 9 kg, and the Great hammerhead shark weighs about 230 kg. Members of this group are usually light grey or brownish grey in colour with a tint of green, and have a white belly.
Members of the Sphyrna group's favourite type of food are stingrays. But they also eat crustaceans like blue crabs and shrimp, molluscs like octopuses and squids, many types of fish like sardines and herrings, and other types of sharks. When they can not find food they start eating each other, but the Great hammerhead shark is known to eat its own young.
Members of this group are mainly viviparous, but in 2007, a bonnethead was found to be capable of asexual reproduction. They give birth to around 12-40 young at a time. Once they are born, young ones come together in groups, and swim towards warmer waters. They then stay together in groups until they are older and big enough to live on their own. They live for around 20–30 years.
- Scalloped Bonnethead, Sphyrna corona
- Whitefin Hammerhead Shark, Sphyrna couardi
- Scalloped Hammerhead Shark, Sphyrna lewini
- Scoophead, Sphyrna media
- Great hammerhead shark, Sphyrna mokarran
- Bonnethead, Sphyrna tiburo
- Smalleye Hammerhead Shark, Sphyrna tudes
- Smooth Hammerhead Shark, Sphyrna zygaena