Do Octopuses Have Bones? Curious Octopus Body Facts Revealed For Kids!

Shirin Biswas
Mar 17, 2023 By Shirin Biswas
Originally Published on Nov 12, 2021
Fact-checked by Niyati Parab
Octopus in a large sea water aquarium.

You must have heard of an octopus and how it has eight arms, but there is so much more to this animal!

Octopuses are fascinating creatures of the sea world, and they have been a subject of research over the past few decades. These animals are not only smart enough to hide from predators but also have specialized body parts that work in unison to create the most stunning view for any human being!

Each time scientists come up with another observation based on octopuses, we cannot help but admire how evolution works. People often confuse the arms of octopuses as tentacles; however, they are clearly a little wrong. Octopuses do not have tentacles like squids. Instead, they have eight arms, which are all specialized.

An octopus's arms have evolved in such a way that each arm is capable of working singularly towards propelling the entire creature. These creatures, in fact, have multiple brains to function so smoothly!

It may seem like octopuses have one too many of each organ or body part, and it is true. In addition to eight arms and several brains, an octopus also has no less than three hearts! Keep reading for some baffling facts and figures about octopuses!

If you enjoyed reading this fun facts article, then why not also check out octopus facts and do moles have eyes right here at Kidadl!

Why does an octopus have nine brains?

Octopuses are fascinating creatures that have a number of characteristics that have been baffling human beings over the years.

They not only have one of the most beautiful body structures but also tend to have abilities that are yet to be seen in other animals on Earth.

An octopus's body is likely to have features, such as many arms and a large head, which will baffle you and give you something to ponder over, but even the organs that this animal has within its body are sure to be of great surprise to you and your friends. Octopuses have no less than nine brains!

In addition to the brain that an octopus has in its head, it also has a brain in each arm.

There have been several kinds of research that tell us about octopuses and their specialized, long arms.

In an exercise to test the intelligence of these creatures, scientists placed food in a maze that the octopus had to figure out.

The maze was created in such a way that there were transparent walls through which the octopus could see the food but could not reach it. After several failed attempts, the octopus was able to use its specialized arm to figure out a way through the maze and reach its food.

The powerful arm muscles that these animals have, in addition to the brain attached to each arm, enable an octopus to carry out extremely clever tasks without much trouble.

Octopuses also have one of the most fascinating body-to-brain ratios, which is typically used in order to camouflage themselves and survive in situations that are otherwise quite tough and challenging.

These animals do not have bones but instead have a hydrostatic skeleton and papillae on each body part, which are controlled by their brains and thereby allowed to shift shapes.

Octopuses can change the texture and appearance of these papillae whenever the situation so demands and are able to get out of sticky situations.

Octopus arms are special and fascinating since they have different properties from that of other squishy creatures of the sea, such as squids and jellyfish. Octopuses are cephalopods, which means that they have eight specialized arms and no tentacles.

Squids and other such sea creatures, on the other hand, have a combination of arms and tentacles. Tentacles are quite different from arms since they usually have more suction packs.

Tentacles have just a pair of suction cavities at the distal parts, while each specialized arm has the entire underside covered in several rows of suction packs. Each specially adapted arm is therefore likely to be of much more use to octopuses than tentacles would be.

These slow-crawling sea creatures are also clever in the way that they can sense animals or humans. This allows octopuses to be able to pick up on certain animals and maintain their distance from others that may seem threatening.

If the question of why octopuses have nine brains ever comes up, it must be understood that sea creatures have their own needs in terms of being safe from predators and other dangers. Hence, the fact that octopuses have a large brain-to-body ratio is most fortunate for them!

How do octopuses move if they have no bone?

Octopuses are invertebrates, and hence, they have no bones. Instead of bones, they have a muscular hydrostatic system. This essentially means that these creatures have muscle tissues that are way more advanced and developed than human beings' muscles.

The three-dimensional muscle fibers in each specialized arm and throughout the rest of the body help the animal in showing exceptional muscle work. There is no skeletal structure in these animals, and it is through muscle fibers that these creatures are able to create jet propulsion-like movements.

The strength and ability of these movements are such that the muscles of one body part work extensively and release such force that the next body part is pushed in the intended direction.

An octopus's muscles work in the most united fashion, and their movements are well coordinated.

Scientists have often pondered how these animals are able to move so gracefully, and the simple answer to this is that, even though there are several arms, each arm has its own brain.

Depending on the direction in which the animal intends to move in, one or two arms work, and the other arms will just allow themselves to be propelled in a certain direction.

Such movements are further enabled by the fact that, rather than a centralized nervous system such as vertebrates have, two-thirds of an octopus's neurons are spread throughout its body, distributed between its arms.

Almost all parts of the octopus's body have at least three nerve endings, which receive unanimous messages from the brain.

Although octopuses lack bones, they have other specialized features which allow them to be quite coordinated and clever in all their movements.

Above all, the common octopus, as well as other octopus species, such as the giant pacific octopus, make use of buoyancy as an advantage. The propelling movements that we see in octopuses are largely caused by the buoyancy factor of water.

Hence, we do owe nature some credit for creating such conditions. Each feature that the animal exhibits has a direct reason, which can be found in its habitat of choice.

Evolution also shows that, since octopuses belong to the class Cephalopoda, it is likely that they never had any bones. Although, it is possible that the development of the specialized muscle fibers is a product of several years of evolution!

Do octopuses have a backbone?

Octopuses are invertebrates, which simply means that they do not have 'vertebrae' or a backbone. This is the basic difference between vertebrates and invertebrates, and hence, the simple answer to the question is a straight no.

These squishy creatures have other muscle functions, such as a muscular hydrostatic system, which allows them to compensate for their lack of bones. Additionally, instead of an exoskeleton, an octopus has a soft mantle.

In fact, it is also well understood that octopuses, as we see them today, would not have had the same level of flexibility had they been vertebrates.

Their lack of bones enables these animals to squeeze through the smallest of places, although the giant Pacific octopus, and other octopuses that are large, still have some trouble in fitting into small spaces.

Human beings and other vertebrates have a rather compromised level of motion and flexibility due to the limits set by their bones. They are usually limited by the rigidity of the bones, which is something that octopuses do not have to face.

What does an octopus have instead of bones?

Now that we know that octopuses do not have bones, you must be interested in knowing what they have instead which enables their movement.

Well, octopuses have special muscle fibers. These muscle fibers are special and of great scientific importance because they shed light on evolutionary factors which have enabled octopuses to be able to move with ease.

These muscle fibers, through screening and research, have been found to be three-dimensional. Such three-dimensional fibers help the arms in gaining great strength in order for the animal to move around fluidly and quickly.

Each fiber also has at least three nerve endings. This creates two phenomena.

First of all, the nerve endings and the messages that they carry to different body parts allow the octopus to be able to move in great jet-like propulsions. Secondly, since octopuses have such an extensive nervous system, they are often extensively sensitive and hence, can sense any danger from many miles away.

In addition to this, octopuses have a brain in each of their eight arms. This also helps in creating strong, yet graceful and purposeful movements across the sea.

Octopuses are amazing to behold, although, they have specific characteristics and abilities which makes it exceptionally tough for humans to spot them on ocean floors.

These animals live in the crevices of rocks, animal debris, and coral reefs. Octopuses are also shy creatures and go into hiding whenever they sense an unknown or dangerous being around them.

In addition to this, octopus skin is specialized and can do some pretty amazing tricks.

One of the main reasons why divers have always found it difficult to spot octopuses is that they can change their skin texture and camouflage themselves with their surroundings. The arms and other parts of an octopus's body are covered in papillae that can contract or expand when signals are received from the brain.

Depending on the intensity of the situation, an octopus can merge itself with its environment by either transforming into a coral or a rock.

To add to the list of features and characteristics that make an octopus special, there is recorded evidence that shows a male octopus using tools. Octopuses are one of the only invertebrates that are smart enough to use objects as tools.

In a particularly baffling image, a veined octopus can be clearly seen collecting coconut shells for future use. This shows that the lack of bones is well compensated for by the other traits that octopuses have imbibed onto themselves throughout the years!

Here at Kidadl, we have carefully created lots of interesting family-friendly facts for everyone to enjoy! If you liked our suggestions for 'Do octopus have bones? Curious octopus body facts revealed for kids!'

then why not take a look at 'Bug vs insect, are they same? Difference between facts for kids! ', or 'Bogle creature: curious facts on Scottish creature revealed for kids!'

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Written by Shirin Biswas

Bachelor of Arts specializing in English Language and Literature

Shirin Biswas picture

Shirin BiswasBachelor of Arts specializing in English Language and Literature

With a degree in English from Amity University, Noida, Shirin has won awards for oratory, acting, and creative writing. She has a wealth of experience as an English teacher, editor, and writer, having previously worked at Quizzy and Big Books Publishing. Her expertise lies in editing study guides for children and creating engaging content.

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Fact-checked by Niyati Parab

Bachelor of Commerce

Niyati Parab picture

Niyati ParabBachelor of Commerce

With a background in digital marketing, Niyati brings her expertise to ensure accuracy and authenticity in every piece of content. She has previously written articles for MuseumFacts, a history web magazine, while also handling its digital marketing. In addition to her marketing skills, Niyati is fluent in six languages and has a Commerce degree from Savitribai Phule Pune University. She has also been recognized for her public speaking abilities, holding the position of Vice President of Education at the Toastmasters Club of Pune, where she won several awards and represented the club in writing and speech contests at the area level.

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