Sharks belong to the family of fish that have skeletons made from cartilage which is the tissue that provides them more flexibility and lighter weight than bone.
They are completely water bound animals that breathe through a series of five to 7 gills that are situated on their sides.
There are over 450 known species of sharks with many more still believed to be undiscovered as of yet. All the species of sharks have several rows of teeth that are razor sharp. They happen to lose their teeth on a regular basis but they constantly have new teeth growing to replace them.
The skin of sharks is quite interesting. Their skin is actually a series of scales that is incredibly smooth and makes their movement in the water easy. This is a fierce predator of the seas that has been around for millions of years now.
Their skin is darker from the top in order to help them blend with the sea floor when viewed from the top. It is lighter and sometimes white from the bottom in order to help them blend with the lighter color of the sea above them when viewed from below. This is one of the many traits which contribute to their reputation as the apex predators in the waters.
Their sleek and streamlined bodies that are lightweight allow them to move easily through the water. Coupled with a body full of powerful muscles, they are able to swim as fast as torpedoes. Their physical appearance makes only part of why they are such fierce predators. They have a keen sense of smell which can allow them to detect a drop of blood in the vast ocean.
Sharks are typically known to travel and hunt alone. They are also known to follow the migratory routes of their prey and there are occasions when sharks come together to prey in schools when there is a lot of prey to be had. Most sharks are known to live 25 to 30 years but there have been cases of sharks living up to 100 years old.
One fun fact about sharks is that most species need to keep swimming constantly. This is because they need to keep the oxygen rich water flowing through their respiratory systems.