Facts about Sharks

Introduction : Sharks are the animals which are included under the phylum chordata and the group vertebrata. They are in the series pisces. i. e. fishes.
Sharks do not have the well -developed skeleton like other fishes becaus  other fishes have the well developed skeleton which are made up of bones. But in sharks, the body is supported by cartilaginous skeleton that means  the skeleton is not made up of bones but of cartilage. Cartilage is not as hard as the bone and it is made up of the material called chondrin. That is the reason the sharks are also known as the cartilaginous fish.Sharks have the muscle tissue made up of cartilage and it makes the fish to be weightless in water.They are adapted excellently to live in water. They have the rough type of skin which is covered with the small toothed scales, which overlap like roof tiles to achieve streamlining and speed in water. Sharks can find their prey over distances of up to 1000 metres. They have ultra sensitive receptors in their snout and lateral sensorial system which detect the slightest vibration in water.They also have the reflective mechanism in their eyes which allows them to distinguish objects in dim light.