Sharks are known to be some of the top predators that inhabit all five of our planet’s oceans. They can be found in shallow coastal waters as well as in the deep blue.
With around 126 different shark species that are found in virtually every marine habitat, these animals have evolved to become superb hunters over the 450 million years that they have been around.
Today, we’re going to take a closer look at the sharks’ anatomy and answer a question that often comes up when discussing sharks. Do sharks have bones?
No, sharks do not have bones. Instead, they have cartilaginous skeletons that are much lighter than true bone which helps them stay buoyant in the water. This cartilaginous tissue is the same stuff that our human ears and nose tips are made of.
Do Sharks Actually Have Any Bones?
Many animals on our planet, including marine animals, have a skeleton. The main functions of a skeleton include support, movement, protection as well as giving their body shape and strength.
With sharks being some of the most notorious predators in the ocean, it’s easy to assume that they would have a skeleton as there is no doubt that they are strong and tough.
However, sharks are from the class Chondrichthyes, which means “cartilage fish”, as opposed to Osteichthyes which means “bony fish”.
Now that we know sharks are cartilage fish, this means that they have a skeleton that is made of cartilage instead of bone. To go even further, sharks don’t even have a single bone in their body. Not one!
Cartilage tissue is softer and more flexible than bone, and it still provides their bodies with shape and structure. It also does the exact same job as a skeleton made from bone, although just not as strong.
Do Sharks Have A Skeleton?
Whilst sharks are cartilage fish, they do still have a skeleton. It’s a cartilage skeleton that is much lighter than bone but still provides them with the support and flexibility they need.
Different parts of a shark body are made from different strengths of cartilage with some areas being more flexible than others.
Areas that are sensitive and need more protection are made from calcified cartilage which has been calcified by calcium salts which makes it a lot tougher.
Sharks’ heads are made from calcified cartilage as this area needs to be tough to protect their brain.
Parts of their jaw are also made from calcified cartilage such as their jaw bone, whilst their snout is made from softer cartilage.
This allows sharks to benefit from the extra protection in the areas they need it most, whilst still reaping the rewards of having a flexible cartilage skeleton.
Why Do Sharks Have A Cartilage Skeleton?
There are actually several benefits to having a cartilage skeleton for sharks over having a skeleton made from bone.
Firstly, cartilage is much lighter than bone which is super important as sharks don’t have a swim bladder.
Instead, they have to rely on their large oil-filled liver to provide them with buoyancy. This means having a heavy bone skeleton would be a disadvantage to them as they would be weighed down by this.
A cartilage skeleton is also much more flexible than one made of bone, which allows sharks to be incredibly agile in the water and make quick turns in the water to catch their prey.
Another major advantage of sharks having a cartilage skeleton is that it allows their jaws to be much more flexible and open wider than they would be able to if they had a bone skeleton.
As they are able to open their mouths wider, they are able to exert much more bite force than they otherwise would, allowing them to lock prey in their jaws and make them some of the most effective predators on the planet.
Sharks’ snouts are also made from soft cartilage, which allows them to act like a bumper that can absorb heavy blows without the shark taking much damage.
As a whole, cartilage is much more useful for a shark than a skeleton made of bone would be. It’s more flexible whilst still being incredibly strong.
The flexibility it provides sharks with is crucial for being an ocean predator as they need to be agile enough to keep up with seals and other prey that is incredibly agile.
Do Sharks Have Vertebrae?
Sharks are classified as vertebrates, which many believe means that they need to have a backbone made from bone.
However, there is nothing in the definition that actually states this. Sharks are still vertebrates because they have a spinal column just like a human.
A shark’s spinal column is made from cartilage, just like the rest of their skeleton. It protects their spinal cord exactly the same way that one made from bone does.
This is because the cartilage that makes up a shark’s spinal column is calcified and incredibly strong and tough enough to provide protection for the spinal column.
Sharks are some of the most effective predators that live on our planet. They have exceptional senses and a strong, powerful body whilst being equipped with razor-sharp teeth.
But do sharks have bones? No, they do not. But why? They simply don’t need bones, cartilage works much more effectively for sharks than bone would.
Cartilage is light, flexible, and also surprisingly strong when calcified. This means sharks can benefit from all of the rewards of cartilage whilst still being protected in the areas they need it most.
The anatomy is sharks is simply fascinating, and it’s easy to assume that sharks would have a skeleton.
However, I hope this post has been insightful today and you’ve learned why sharks do not need a skeleton made from bone and are in fact much better off without one.
I appreciate you taking the time to read this post, feel free to stick around to learn more about sharks and lots of other marine wildlife that we write about here at MarinePatch.
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Hi, I’m George – the founder of MarinePatch. I created this blog as marine wildlife has been my passion for many years and I’ve spent decades learning and dedicating myself to documenting all I can about the topic.