Shark. Sharks are amazing fish that have been around since long before the dinosaurs existed. Details all the major shark species with over ten pictures and an overview. Links to sharks sites for further information. Shark species including: Great White Shark, Hammerhead Shark, Tiger Shark, Bull Shark and Whale Shark.

Sharks

Sharks are amazing fish that have been around since long before the dinosaurs existed. Due to extensive scientific research over the years, we now know more information on sharks than ever before.

Unlike bony fish, sharks have no bones; their skeleton is made of cartilage, which is a tough, fibrous substance, not nearly as hard as bone. Sharks also have no swim bladder (like bony fish do).

There are many different species of sharks that range in size from the size of a person's hand to bigger than a bus. Fully-grown sharks range in size from seven inches (18 cm) long (the Spined Pygmy shark), up to 50 feet (15 m) long (the Whale shark).

Most sharks are intermediate in size, and are about the same size as people, five to seven feet (1.5-2.1 m) long. Half of the 368 shark species are less than 39 inches (one metre) long.

Sharks have a variety of body shapes. Most sharks have streamlined, torpedo-shaped bodies that glide easily through the water. Some bottom-dwelling sharks (e.g. the angelshark) have flattened bodies that allow them to hide in the sand of the ocean bed. Some sharks have an elongated body shape (e.g., cookiecutter sharks and wobbegongs).

Sawsharks have elongated snouts, thresher sharks have a tremendously elongated upper tail fin, which they use to stun prey, and hammerheads have extraordinarily wide heads. The goblin shark has a large, pointed protuberance on its head; its purpose is unknown.

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, colour, 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, which includes the sharks, rays, and skates.

Sharks are a type of fish that have no bones, only cartilage. Some parts of their skeleton, like their vertebrae, are calcified. Cartilage, a strong fibrous substance, softer than bone; our nose and ears are made of cartilage.

Sharks belong to the group of fishes called Elasmobranchii, which also includes the rays, skates, and ratfish. The Elasmobranchii are all fish that have no bones, only cartilage.

Sharks may have up to 3,000 teeth at one time. Most sharks do not chew their food, but gulp it down whole it in large pieces. The teeth are arranged in rows; when one tooth is damaged or lost, another replaces it. Most sharks have about five rows of teeth at any time. The front set is the largest and does most of the work.

Sharks vary greatly in their diets. Some (like the great white, mako, tiger, and hammerhead) are swift predators that eat fish, squid, other sharks, and marine mammals.

Sharks may have up to 3,000 teeth at one time. Most sharks do not chew their food, but gulp it down whole it in large pieces. The teeth are arranged in rows; when one tooth is damaged or lost, another replaces it. Most sharks have about five rows of teeth at any time. The front set is the largest and does most of the work.

Sharks vary greatly in their diets. Some (like the great white, mako, tiger, and hammerhead) are swift predators that eat fish, squid, other sharks, and marine mammals.

Some (like the zebra horn shark, angelshark, and wobbegong) are slow-swimming predators that crush and eat shellfish (crabs and clams) from the ocean floor.

Others (like the whale shark, the basking shark, and the megamouth) are filter feeders that sieve tiny bits of plankton and small animals from the water as they swim with open mouths. They eat huge amounts of these tiny animals and plants.

Fish don't sleep in the same way that we do, but they have active and inactive periods. Some sharks (like the nurse shark) have been observed resting motionless on the sea floor. Others have to keep moving in order to breathe.

Sharks do not normally attack people.The sharks that are the most dangerous to people are the great white shark, the tiger shark, the bull shark, and the oceanic whitetip shark. The bull shark is the most frequent attacker of people as it swims in very shallow waters where people swim and is a very plentiful shark. Some of the other sharks that are known to have attacked people include the grey shark, blue shark, hammerhead shark, mako shark, nurse shark, lemon shark, blacktip reef shark, wobbegongs, sandtiger, spitting sharks, and the porbeagle. Some people believe that sharks mistake people (especially people swimming on surf boards) for seals and sea lions, some of their favourite foods.

Sharks live in oceans and seas all over the world, and even in some rivers and lakes, especially in warmer waters. Some sharks live near the surface, some live deep in the water, and others live on or near the ocean floor. Pelagic sharks (living in the open ocean) include the great white shark, the basking shark, etc. Benthic sharks (living at the ocean floor) include the zebra horn shark, the wobbegongs, and the angelshark, which usually have flattened, camouflaged bodies that let them hide in the seabed.

Some sharks even venture many miles up into the fresh water of rivers like the Mississippi in the USA and the Amazon in Brazil. The bull shark (Carcharhinus leucas) sometimes ventures into fresh water.

Some sharks live in relatively warm waters (hammerheads, bull sharks, and tiger sharks). Other sharks, such as the thresher, mako, basking and blue shark, live in temperate water (which is neither hot nor cold). Others, including the dogfish, Greenland, and goblin, live in cool waters. Other sharks stay in the same region their entire lives while others travel across oceans.

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Information on sharks

Sharks