Octopuses are some of the most weird and wonderful creatures of the ocean. They have eight tentacles that are covered in suction cups, giving them a stick grip to grasp onto prey.
They are also some of the smartest animals in the ocean, with some species such as the Giant Pacific Octopus having nine brains!
In this post, we’re going to take a closer look at the Octopuses anatomy, and answer a question that many ask when discussing Octopuses. Do Octopuses have bones?
No, Octopuses do not have bones. They are invertebrates which means that they have no bones, backbone or vertebral column.
Do Octopus Actually Have Bones?
Octopuses are known to be incredible escape artists. They are able to fit into tiny spaces such as crab traps in order to steal their food and escape without the fishermen being none the wiser.
They are able to do this because they have no bones, allowing them to be incredibly mobile. Octopuses are invertebrates, meaning they do not have a vertebral column or spine.
Does An Octopus Have A Skeleton?
As the Octopus is an invertebrate, this means that it does not have a skeleton like many other creatures.
Octopuses are cephalopods, which includes Sea Sponges, Jellyfish, Squid, Cuttlefish and more. These animas are mollusks, and have no trace of a skeleton, neither internal or external.
The early ancestors of Octopuses over 500 million years ago were mollusks, but the Octopus branched off and lost its shell.
This change likely happened during the Jurassic and Cretaceous period, when Octopuses lost their snail-like shell and became the animals they are today.
How Do Octopuses Move Without A Skeleton?
For many animals, a skeleton is the foundation that allows them to move around freely. So how do Octopuses move around without a skeleton?
Well, given that Octopuses live in the ocean, they can use their buoyancy to their advantage. This makes moving in the water easier, especially when you have eight long tentacles.
An Octopuses tentacles are full of muscles that allow them to swim through the water, quite fast too with some Octopuses being able to swim as fast as 25mph.
The muscles in an Octopuses tentacles are similar to the muscles in our tongue. We don’t have bones in our tongue but we are still able to move it any stretch without issue.
Some species of Octopus such as the Giant Pacific have a hydrostatic skeleton. This is formed by a compartment in the body filled with aqueous fluid, this is called the coelom.
This compartment utilises hydrostatic pressure to support organs of the coelom. Some other invertebrates such as Earthworms have this type of skeleton.
Movement is capable because of the muscles surrounding the coelom, with the hydrostatic skeleton contracting to change the coeloms shape.
Why Octopuses Don’t Need Bones
The fact that Octopuses don’t have a skeleton is actually an advantage for them, allowing them to squeeze into places that they otherwise couldn’t if they had bones.
Octopuses are super intelligent, and are master escape artists. They can work their way in and out of lobster pots and crab traps to steal prey effortlessly.
They are able to contour their bodies in amazing ways, allowing them to catch prey as well as hide from predators in ways that they couldn’t before.
If Octopuses see a shark for example, they are able to camouflage and hide in a shell, making them almost impossible to see.
This flexibility comes in handy when living in an ocean that is full of hungry predators. They are able to change shape in a number of different ways to stay hidden.
Living underwater is another reason why Octopuses don’t need bones. If you’ve even been in a swimming pool then you’ll know how much lighter our bodies are.
This is the same for Octopuses, and with tentacles full of muscles, it’s easy to move around therefore no skeleton is required.
How Do Octopuses Maintain Shape?
With Octopuses not having a skeleton, you would think that they would have no control of their body shape, but this is not the case.
The Octopus uses other anatomical features to help keeps its shape defined. They have well-defined muscle tissue that provides a strong overall structure and allows movement in its tentacles.
They also have incredibly tough, strong skin that also help them to maintain shape.
Do Octopuses Have Teeth?
Octopuses lack any form of rigid structure in their body, no teeth, no bones, but they do have a beak!
All Octopuses have a beak that is used as a mouth. However, this beak is not made of bone, and is made from chitin, which is the same material that makes up exoskeletons of insects.
They use their beaks in order to crush their food before eating it, and also to use their venom to paralyze prey before consuming it.
Octopuses contain venom that they will use to immobilize prey. For example, when hunting crabs, they use their sticky arms to get behind the crab before flipping it over.
They then use their beak to pierce the crabs soft underbelly and inject it with venom.
The venom immediately starts to liquify the crabs insides, allowing the Octopus to suck out its insides and leave behind only the crabs empty shell. Pretty horrific if you ask me!
Octopuses also have something called a radula. This is a tongue like structure that is covered in tiny denticles which are essentially incredibly small teeth.
The radula is used to help the Octopus break down food before digesting it. An Octopuses beak is their only weapon, which is why when they attack they pull their prey in towards their beak.
Although bites are rare from Octopuses, if they are being handled poorly they have been known to bite people using their beak.
This sharp, parrot-like beak can really hurt too, and leave people with a nasty wound.
Octopuses are some of the most remarkable animals on the planet. They are probably the closest animals that we know of to resemble alien life.
Intelligent, flexible and unique in their own right, Octopuses are surprising scientists more and more with new findings.
Despite them not having any bones, they still manage just fine in the oceans, and it even gives them advantaged in some ways.
These amazing animals are even able to regrow their limbs due to not having bones, which means if one tentacle gets infected, they can bite it off and regrow it. Pretty cool, right?
Although these animals have no skeleton or bones, they still manage to hunt prey, avoid predators and protect their young.
Hopefully this post has been insightful and you’ve learned something new about Octopuses today. If you have enjoyed this post, feel free to stick around and learn more about these weird and wonderful creatures.
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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.