There are about 368 different species of sharks, which are divided into 30 families.
These different families of sharks are very different in the way they look, live, and eat.
They have different shapes, sizes, color, fins, teeth, habitat, diet, personality, method of reproduction, and other attributes.
Some types of shark are very rare (like the great white shark and the megamouth) and some are quite common (like the dogfish shark and bull shark). Sharks belong to the group of cartilagenous fish, the Elasmobranchii, that includes the sharks, rays, and skates.
Great White
Father of all man-eaters, the great white is the second-largest shark.
The biggest recorded specimens include a great white caught in 1978 off the coast of the Azores and
measuring more than 29 feet, and a 21-foot great white near Cuba that was reported to weigh more than
7000 pounds.
The great white is the only shark that can hold its head above water to see what's happening on the
surface. This shark is believed to be territorial, returning to the same location every year.
The size of its territory depends on available food and the number of other sharks present to help
eat it. They frequently live near seal colonies, often in groups designated by size and sex.
Along the West Coast of the U.S., great whites feed on sea lions and elephant, harbor and fur
seals; in the western north Atlantic they are thought to feed primarily on dead whales.
The area that extends from Bodega Bay down to the south end of Monterey Bay and out to the Farallon
Islands, known as "the red triangle," is particularly well-known for its abundance of great white
sharks. At almost any time, people visiting Aņo Nuevo, the Farallones or Guadalupe Island can observe
seals with fresh or healing shark wounds.
Great whites feed infrequently, although their exact time between meals is unknown.
(One 1982 study showed that a 15-foot shark can live for about 45 days on 66 pounds of whale blubber).
A great white attack usually consists of one massive bite taken from under or behind the chosen prey.
(Attacks to the head are rare.)
As the shark's jaws open, its whole head changes shape: Its mouth moves to the front, and its snout
bends up out of the way. During the attack the shark cannot see its victim, instead relying on its
electronic field sensors to keep track of the prey.
The moments after the initial attack are crucial: Humans who have been bitten once generally can
escape if they get help from a buddy or make it to shore on their own. But sharks usually lose
interest after the first bite. (Maybe it's our fast-foot diet.)
Tiger Sharks
Young members of this warm-water shark sport prominent tiger-like stripes that fade as they age.
Reports of two 21-foot tiger sharks caught in Australian shark nets, and unconfirmed fishermen' reports of an 18.5-foot shark caught in New South Wales and a 12-foot shark caught in the Gulf of Panama, are among the largest sightings.
In addition to eating seals, sea lions, and the variety of refuse listed above, hungry tiger sharks can munch right through the shells of large sea turtles.
Hunger probably prompted a tiger shark to attack speedsailor Roddy Lewis while he surfed a remote spot in Maui's Wailuaiki Bay last spring. Several elements were against Lewis--the water was murky, sticks and other objects floated nearby, and he and his buddy had paddled to an isolated spot to escape the crowd. In fact, Lewis says he thought, "This is perfect water for sharks ...," about five seconds before the attack.
As the 10- to 12-foot shark gripped his leg and tried to pull him under, Lewis beat it on the side of the head and drove it off, then managed to catch a wave and surf in to shore. Doctors managed to save Lewis's leg, and he reportedly is planning to resume surfing.
Just about every shark enthusiast has one species that is his or her absolute, hands-down favorite. Some favor the Great White. Others hold in particularly high regard the strange and wonderful hammerheads, Goblin, or thresher sharks. Still others - divers mostly - regard as deeply totemic whichever shark species they first encountered in the wild. The precise combination of favorite shark species and the reasons for choosing it are as many and varied as shark enthusiasts themselves.