Before the dinosaurs “Things you don't know about sharks”

Sharks have been around since long before the existence of dinosaurs and they are one of the very few creatures that did not evolve and became the same as they were millions of years ago and they live in waters all over the world, in all oceans, and even in some rivers and lakes.

Unlike bone fish, sharks do not have bones, and their skeleton is made of cartilage, which is a mixture of hard myeloma, and fibrous substance mixed with it.

And sharks have a variety of body shapes.  Most sharks have streamlined, torpedo-shaped bodies that glide easily through the water.  Some bottom-dwelling sharks such as: "angelshark" have flattened bodies that allow them to hide in the sand from the ocean floor.

Some sharks have an elongated body shape. For example, cookiecutter sharks and wobbegongs Sawsharks have elongated snouts, thresher sharks have a significantly elongated upper fin tail which they use to stun prey, and hammerheads have extremely broad heads.  The puck shark has a large, upside-down protrusion, and its purpose is unknown.

There are about 368 different species of sharks, which are divided into 30 families.  These families are different from sharks and very different in their view, and their method of predation.

They have different shapes, sizes, colors, fins, teeth, diet, method of reproduction, and other traits.

Some types of sharks are very rare such as: the great white and the megamouth.  And some are very common such as: the dog shark and the bull shark.