Sharks are wonderful creatures. From the great white shark to the large and mysterious whale shark, these dangerous animals roam the oceans far and wide.
It’s true that sharks have zero bones or no bones in their body. Did you then think that they are floppy and will just bend all over? Not really. No bones do not make them floppy like a jellyfish.
That is because they still have well-built skeletons. Creatures with skeletons are called vertebrates. But, if sharks have no bones, what are their skeletons made of?
Unlike the other vertebrates in place of the hard bones, sharks have cartilage. Cartilage is the same thing that we find in our ears and nose. Cartilage is a softer tissue and it is more flexible than bone. They are strong enough to hold muscle and skin in place.
The skeletons of sharks are made out of cartilage. It makes them much lighter and helps them to float.
There are many fishes in the ocean that are cartilage fishes. These have no bones. All such fishes are called Chondrichthyes and the bony fishes are called Osteichthyes.
Some parts of the shark’s skeleton have heavier cartilage than others. Different parts of a shark’s skeleton have very different types of cartilage. They have different structures and functions. But the whole skeleton, including the jaws, is made of cartilage. Shark “skulls” are also made of cartilage which is called chondrocranium.
What about shark teeth? Well, like our teeth, shark teeth are made of a tissue called dentin. They are stronger and thicker tissues.
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