Sharks are fish. However, they do not have bones like other fish. Their skeleton is made of cartilage. This is the same bendable material that is in your ears!
They also do not have a swim bladder, the air filled balloon-like organ that keeps most fish upright. Sharks have gill slits but no gill-cover, which is common to most bony fish. Because they have no swim bladder to keep them buoyant, sharks sink when not swimming. Shark’s bodies are heavier than water and most sharks are constantly on the move. By moving forward with their mouths open,
sharks move water across their gills for breathing. The larger species produce live young that are
fully formed, miniature versions of their parents. Mother sharks offer no food or protection for their
young. Young sharks do have a fighting chance, though, as they are born with a full set of teeth and the ability to swim.
Some Kinds of Sharks
2) The nurse shark is a slow sluggish, shark. It is often seen taking a rest on the bottom. This shark feeds on bottom dwelling animals such as crabs and shrimp. They can be recognized by the barbels (fleshy apendages) that hang below their bottom.
3) The Whalefish Shark is the largest fish in the ocean. It can reach up to 50 feet and weigh about 30 tons. The whalefish eats plankton. It swims in warm waters near the equator. It filters meals as it swims with its mouth open. It is not threat to humans
4) The hammerhead shark is named for unusual shape of their heads. Their wide heads help them to steer through the water. Hammerheads are common in the warm ocean waters. They eat fish and squid.
Site recommended : http://www.nationalgeographic.com/sharks/
white shark picture
Interesting Shark Facts
Just as humans rule the land, sharks rule the sea! Many people fear sharks, because they hear stories about sharks killing and eating humans. Actually, most sharks are not dangerous!
More people are killed by bee stings than by shark attacks.
More than 90% of people who are attacked by sharks survive the attack.
Sharks attack more men than women. No one knows why this is the case.
The bull shark is the only shark that can live in both fresh and salt water. A bull shark may have been responsible for a shark attack that happened in a creek in New Jersey back in 1916.
The largest shark teeth found belonged to a Carcharodon Magaloden shark and are 6 inches long. This shark is extinct and lived more than 4.5 million years ago
Sharks do not sleep the same way as humans do. They might seem as if they are sleeping but they are really just resting!
Sharks are strong, healthy creatures. No other living thing can take better care of itself than a shark can! Like humans, sharks are at the top of the food chain.
Sharks never get cancer! Their cartilage is used in being studied with the hope of developing anti-cancer drugs.
Sharks have been around for more than 300 million years! They were around before dinosaurs!
Sharks’ bodies are heavier than the sea, so if they stop moving they sink. If they want to stay afloat, they must keep moving!
There are about 350 different types of sharks, but researchers think there are other sharks that haven’t been discovered yet!
The dwarf shark is as small as your hand, while the whale shark can be as large as a school bus!
A shark is one of the best hunters in the world. Even their little pups go out looking for food.
A shark’s hunger can be satisfied with one good meal. The meal can last a long time because a shark uses little energy to swim. Some sharks hold food in their stomachs without it being digested. If they eat a big meal, it can last three or more months!