Sharks have spinal structures in their skeletal system, which makes them vertebrates. However, unlike other vertebrates, they don’t have any true bones but instead have cartilage that gives them a flexible yet strong body structure.
Since sharks are cartilaginous, they don’t have any bone marrow to produce any new red blood cells. As such, they have adapted a different way to produce new red blood cells through their spleen and other organs.
What are cartilages?
Cartilages are made up of collagen and calcium salts, making them flexible yet strong. It allows sharks and other cartilaginous fish to make quick turns in the water without damaging their bodies.
Cartilage is not as hard as bone and isn’t as strong, which is why cartilaginous fish can’t afford to get hurt, or else their bones won’t heal as quickly. This makes them some of the most impressive hunters in the ocean because they have to be so careful when they are hunting and feeding.
Are there other fishes that are cartilaginous?
Other fish that are cartilaginous are skates, rays, sawfish, and chimeras. These cartilaginous fish, along with the shark, are considered members of the class “Chondrichthyes,” which means “cartilage” and “fish” in Greek.
Sharks and other Chondrichthyes are considered vertebrates since they have a spinal structure, but unlike other vertebrates, they are made out of cartilage instead of bones. This makes them incredibly flexible and able to move quickly in the water without damaging their bodies.