The Perfect Machines
Throughout the years, sharks have gotten a bad reputation due to negative media and fictional works demonizing them and depicting them as heartless beasts. While it is true that sharks are deadly, it is only because of millions of years spent in the ocean and adapting in order to survive.
The shark's missile-shaped body is perfectly designed for moving at high speeds in the water. Combined with the heterocercal tail (a tail that has different sized fins on the top and bottom), the shark's entire construction has evolved into a machine designated for moving at high speeds in short bursts, and the iconic dorsal fin aids the shark's balance.
Sharks are known for their rows of razor sharp teeth that rip through a variety of things including flesh, wood, and bone. There are a number of types of shark teeth that vary according to the diet of the shark.See More Teeth
A shark's mouth is found on its underside and has a downward curve that makes it look like it's constantly frowning. This is because of how the jaw is attached to the rest of the shark, but it's not. Because the jaw is not connected, it allows the shark to unhinge it and take a bigger bite out of prey.
Sharks don't have bones like people or other animals do. Sharks have a skeleton, but the pieces of their skeleton are actually made of a substance called cartilage instead of bone. This makes them light enough to swim instead of sinking to the bottom of the ocean.
Not much is known about the shark's ancestors. This is because the shark skeleton is made of cartilage. When exposed to saltwater and currents, cartilage becomes fragile and weathers away quickly.More History