Small sharks are highly variable in the size and shape of their cephalofoils, said Martin. The winghead shark, for example, has a laterally expanded head that is about half the size of its roughly 4-foot body length. At the other end of the spectrum is the bonnethead shark, about 3 feet long but which has the smallest cephalofoil of all hammerhead species -- a protrusion that resembles the head of a shovel, Martin said.
Martin said that hammerheads are an ideal biological study subject in part because of some important similarities to humans. Both have slow growth rates, mature late in life, give live birth and have relatively few offspring. While hammerheads may have a dozen or more pups, other oceanic fish regularly lay millions of eggs. Hammerheads generally live for about 30 years, he said.
While hammerhead sharks appear intimidating, attacks on humans are extremely rare, said Martin. Hammerheads have relatively small mouths facing downward that are used to grab food like fish, shellfish, shrimp, squid, octopuses and stingrays. "If you see a hammerhead, I'd say grab your camera and jump into the water," said Martin.
"Hammerheads are special fish, and there is nothing that remotely resembles them anywhere on the planet," said Martin. Unfortunately, hammerheads -- like most shark species -- are on the decline. In addition to being overfished, sharks often are the victims of a technique known as finning, in which fishermen catch them, cut off their fins for use in delicacy soups, and return them to the water to die, Martin said. Shark meat also is used for fertilizer and to make pet food.
There currently are 233 shark species on
|Contact: Andrew Martin|
University of Colorado at Boulder