Hammerhead Sharks

As you might guess by its name, the great hammerhead (Sphyrna mokarran) is the largest of the hammerhead sharks. These animals can reach a maximum length of about 20 feet (6 m), although they are about 12 feet (3.6 m) long on average. They can be distinguished from other hammerheads by their large "hammer," which has a notch in the middle.

Great hammerheads may be found both close to shore and offshore, in warm temperate and tropical waters. They live in the Atlantic, Pacific, and Indian Oceans; the Mediterranean and Black Seas; and Arabian Gulf.

The smooth hammerhead (Sphyrna zygaena) is another large shark that can grow to about 13 feet (4 m) in length. These types have a large "hammer" head but without a notch in its center.

Smooth hammerheads are a widely distributed hammerhead shark— they may be found as far north as Canada and along the U.S. coast down to the Caribbean and off of California and Hawaii. They have even been seen in freshwater in Florida's Indian River. These types are also found in the western Pacific, around Australia, South America, Europe, and Africa.

The scalloped hammerhead (Sphyrna lewini) can also reach lengths of more than 13 feet (4 m). This species' head has narrow blades, and the outer edge has a notch in the center and indentations resembling the shell of some scallops.

Scalloped hammerheads are found in inshore (even in bays and estuaries), water about 900 feet (274 m) deep. They are found in the western Atlantic Ocean from New Jersey to Uruguay; in the eastern Atlantic from the Mediterranean Sea to Namibia; in the Pacific Ocean from Southern California to South America and off of Hawaii; in the Red Sea; the Indian Ocean; and the western Pacific Ocean from Japan down to Australia.

The scalloped bonnethead (Sphyrna corona) or mallethead shark is a small shark that reaches maximum lengths of about 3 feet (1 m).

Scalloped bonnethead sharks have a head that is more rounded than some other hammerheads and is shaped more like a mallet than a hammer. These sharks are not well known and are found in a fairly small range, in the eastern Pacific from Mexico to Peru.

The winghead shark (Eusphyra blochii), or slender hammerhead, has a very large, wing-shaped head with narrow blades. These sharks are medium-sized, with maximum lengths of about 6 feet (1.8 m).

Winghead sharks are found in shallow, tropical waters in the Indo-West Pacific from the Persian Gulf to the Phillippines and from China to Australia.

The scoophead shark (Sphyrna media) has a broad, mallet-shaped head with shallow indentations. These sharks can grow to a maximum length of about 5 feet (1.5 m).

Little is known about the biology and behavior of these sharks, which are found in the eastern Pacific from the Gulf of California to Peru and in the western Atlantic Ocean from Panama to Brazil.

Bonnethead sharks (Sphyrna tiburo) are about the same size as scoophead sharks—they can reach a maximum length of about 5 feet (1.5 m). They have a narrow, shovel-shaped head.

Bonnethead sharks are found in tropical waters in the eastern Pacific and western Atlantic Oceans.

Smalleye hammerhead sharks (Sphyrna tudes) also reach a maximum length of about 5 feet (1.5). They have a broad, arched, mallet-shaped head with a deep indentation in its center.

Smalleye hammerheads are found off of the eastern coast of South America.

Whitefin hammerheads (Sphyrna couardi) are a large hammerhead that can reach a maximum length of more than 9 feet (2.7 m). Whitefin hammerheads have a broad head with narrow blades. These sharks are found in tropical waters in the eastern Atlantic off the coast of Africa.

The Carolina hammerhead (Sphyrna gilberti) was named in 2013.  It is a species that looks nearly identical to the scalloped hammerhead, but it has 10 fewer vertebrae. It is also genetically different from the scalloped hammerhead and other shark species. If this hammerhead was discovered as recently as 2013, how many other shark species are out there that we don't know about?!