Southern Keeled Octopus walking seafloor Matt Testoni
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Do Octopus Have Bones?

Frequently Asked Questions, Octopus Anatomy

What if you live in a world where you’re able to be weightless all day and supported by a cocoon of water? Do you NEED bones? Nope. So, do octopus have bones? They have ZERO bones, and yet they still have structure to them. How do they manage to be anything more than a blob? Let’s take a look at how octopuses maintain their shape and have lived a happy bone-free life in the ocean!

Maori Octopus By: Matt Testoni

An octopus is mostly made up of arms and suckers, which they use for all sorts of things: 

To perform all these activities, an octopus’s 8 important appendages must be flexible, muscular, and rigid!

… But how are they able to be ridged without bones or a spine?

Octopus have no bones gif image
Octopus have no bones! By: Lawrence Scheele

Does an octopus have a skeleton?

With the help of the dense muscles that make up their arms, they pressurize water inside their bodies, allowing them to keep their shape. All an octopus has to do is flex to make its arm rigid! 

By controlling the pressure that they exert on the water inside their bodies, they can make their arm like jelly to get through nooks and crannies in rocks and then stiffen up to grab hold of a prey item. 

Unlike bone structures with rigid skeletal elements, the octopus can:

  • Bend
  • Twist
  • Elongate
  • Shorten at MULTIPLE locations simultaneously!
Coconut Octopus creates make shift home in seconds! ( Amphioctopus marginatus )

Rate this makeshift home from 1 to 8!🥥 Coconut Octopuses are also nicknamed ‘veined octopus’ because of the dark branched veins that run down their body and arms.🛡This specific species seem to be super in touch with how vulnerable & squishy their bodies are— as they grow larger, they’ll start shopping around to make their armor more efficient.🤿 Some scuba diver friends of ours have mentioned that they’ll sometimes find and suggest better living arrangements by placing a shell or coconut within a close distance of the coconut octopus.🐚 The octopus will tip toe over and inspect it— and then carefully decide if they wanna ditch a piece of their collection. 

These cute coconut octos have been observed carrying objects over 70 feet by “stilt walking”!🥥 They’ll flip a coconut half over— or conch shell, bivalve shell, or honestly whatever they can find, and then drape their arms over the side and begin stilt walking with their predator proof bunkers.🐙 💨 Some, like the one in the video above, will even bury their make-shift homes in the ocean floor, leave to hunt for food, and then blow jets of water to extract their mobile homes.🧠 These sophisticated cognitive abilities are notable because they’re an example of the octopus using short & long term memory to plan for future events!📖 Depending on their learned experiences, the coconut octopus figures out what works best to thrive in their given environment.Smart huh? If ya read this far, comment what this video reminds you of… I think of the show chef masters when they all run to the kitchen to grab ingredients for their challenges. Lol. 
Hope you learned something new! 🎶: Spider-Man- Kolektivo
🎥: Stock media provided by MikhailProtopopov / Pond5

Posted by Octonation – The Largest Octopus Fan Club on Tuesday, March 23, 2021
By: MikhailProtopopov / Pond5

🐙 Octopus Fun Fact

What’s cool is that it’s not only the arms of the octopus that consists of muscular hydrostats… it’s basically the ENTIRE octopus. 

Muscular-hydrostatic support is used to:

  • Create pressure in the suckers
  • Support and create a movement of the beaks
  • Provide muscular action for the mantle during respiration and jet propulsion
  • Provide support and muscular action to a variety of other structures and organs!

👽 or 🐙 🤔🎥: @_bugdreamer_ 🧠 Can you imagine ALL of your bodily organs suspended in different free floating areas of your head?! An octopus could 😂🐙Octopuses are able to fit into small spaces, squeeze through tiny openings and cracks and hide in areas that would be inaccessible to most predators and vertebrate creatures.💀🚫 Octopuses don’t really have the need for the structural support of bones because they live in a fluid underwater environment. It actually serves them better to be super flexible in many ways!🐚 However, they do rely on natural structures of the ocean for protection such as dens, rocks, and for some species, shells and coconuts.💙Just another reason to fall in love nation!🤓 If you read this far comment “Octopus Cyanea!” The octopus cyanea (day octopus) can identified by it’s false eye spots & rows of white spots down their arms! 👀Who else do know that would be mesmerized by this?! Okay is it just us or does that fish in the beginning kinda look like the 🇺🇸 flag? #blueplanet #ocean #sea #nature #marinebiology #myoctopusteacher #seacreatures #natgeo #nationalgeographic #natgeotravel #natgeowild #underwater #underwaterphotography #blackwater #scubadiving #scuba #diving #animals #wildlife #alien #science #photography #instagram #explore #adventure #cool #education #naturephotography #HappyNewYear

Posted by Octonation – The Largest Octopus Fan Club on Sunday, September 5, 2021
By: Bug Dreamer

Just out for a stroll…

Octopuses also use their unique skeleton to push heavy objects away and carry objects around for protection by rising up and “stilt walking.” 

The Coconut Octopus is capable of bipedal movement, which means ‘walking’ on two arms with a ‘rolling gait’, although sometimes they’ll use three or four. The behavior above is known as “the moving rock” trick, where an octopus will keep most of its arms tucked in close to its body and glide across the ocean floor.

While the hydrostatic skeleton is the most prevalent skeletal form amongst invertebrates, it is also found in vertebrates. An elephant’s trunk and your tongue are also examples of a hydrostatic skeletal system at work! 

Note: Learn more about this amazing system and all the cool stuff octopuses can do with their arms. 

Caption this Video! Coconut Octopus Running along the ocean floor!

Caption this! “The Original Moonwalker” 🎥: bugDreamer.com🦴Octopuses are boneless! (Despite how much confusion that octopus skeleton Halloween prop has caused — have you seen it? Haha) They do have something called a hydrostatic skeleton though—Which, in water, is way cooler than our pesky bones! 💦 Unlike bone structures with rigid skeletal elements, the octopus can bend, twist, elongate, (and more) at MULTIPLE locations simultaneously. 🐘 An elephants trunk and your tongue is another example of a hydrostatic skeletal system at play! 👅 💪 Octopus can flex their arms to push heavy objects away & carry objects around for protection by rising up and “stilt walking” ⁣⁣⁣⁣⁣⁣ ⁣⁣⁣⁣⁣⁣⁣⁣ 🥥 The coconut octopus is also capable of bipedal movement which means ‘walking’ on two arms with a ‘rolling gait’⁣⁣⁣⁣⁣⁣⁣ although sometimes they’ll use three or four. ⁣ 🪨 The behavior above is known as "the moving rock" trick, where an octopus will keep the majority of their arms tucked in close to their bodies and glide across the ocean floor. 🤩Mesmerizing to watch huh? If ya read this far, comment hydrostatic skeleton! And wahlah! Just like that your OctoIQ went up! 🐙 📈 🧠

Posted by Octonation – The Largest Octopus Fan Club on Friday, October 22, 2021
By: Bug Dreamer

🐙 Octopus Fun Fact

Invertebrates all over the world have nifty ways of keeping their body shape without the help of bones.

Lobsters and crabs have exoskeletons made from chitin that they need to molt out of to grow. Jellyfish are made up of a literal jelly-like substance called mesoglea, and sea sponges are a dense network of fibers made out of collagen.

Why do octopuses need no bones? 

Octopuses don’t really have the need for the structural support of bones because many live in complex environments or habitats with lots of holes and crevices. It serves them better to be super flexible in many ways!

An octopus can fit into small spaces, squeeze through tiny openings and cracks and hide in areas that would be inaccessible to most predators, which are vertebrates. 

Caption this video! – Clever coconut octopus showing us the perks of having NO bones!

⬆️ Caption this Video! “If it fits…I sits!”🎥: Ben Trayner of Manta Dive Gili Trawangan⛔️ Have you ever noticed that the bar-shaped pupils in octopus eyes always stay horizontal, no matter what their body is doing? 🚫 Octopus pupils never point up or down like cat pupils do because they have nifty balance receptors called statocysts! ^ↀᴥↀ^ Meow, let’s continue…☯️ Statocysts are the so-called 'organ of equilibrium' because they help octopuses balance in water.🔘 Behind each octopus eye Imagine a little pouch filled with sensory hairs…inside that pouch there are small mineralized "ball bearings" that roll around in response to movement and gravity. This system, although super simplified, , ensures octopus pupils remain horizontal no matter what– isn't that cool? ⛔️⛔️😅 Octopuses are food to many different animals. They need to stay safe!⛔️ Their horizontal pupil is an epic superpower that lets the octopus see in almost every direction without moving their eyes!🤓 Long story short, you can’t sneak up on an octo! If ya read this far, did ya learn something new? What did you find most interesting?Also congrats— you just raised your OctoIQ— you’re totally ready for Trivia, comment ⛔️⛔️ below!

Posted by Octonation – The Largest Octopus Fan Club on Monday, August 23, 2021
By: Manta Dive Gili Trawangan

Octopuses seem to have infinite degrees of freedom by being flexible enough to squeeze their whole body into impossibly tiny spaces! How tiny? National Geographic observed a 600lb octopus squeezing through a hole the size of a quarter— isn’t that nuts?!

While it’s handy to be crazy flexible, it also makes you a squishy treat, so octopuses rely on natural structures of the ocean for protection, such as rocks, corals, and for some species, shells, and coconuts. 

They also have fantastic camouflage skills to pull out of their bag of tricks as well.

This is why octopus prefer to walk…

Caption this video! 🐙💨🎥: Manta Dive Gili Trawangan (Ben Trayner)The Blue-ringed octopus, along with many other octopuses, are not great swimmers! Why?Well, the amount of energy needed to jet away puts a tremendous strain on their bodies. *Remember, the mantle contains all their free floating bodily organs — so things get pretty cramped when they completely exhale! Can you Imagine being underwater and using all the air in your lungs to move your body in any direction— how quickly do you think you could get to the other side of a pool? (by the way please don’t attempt this 😅) For the Blue ringed octopus… the tiny amount of water brought into their small mantle cavity would have to be expelled at such a high speed— that they’re seriously better off walking. In fact, records of aortic pressure and blood flow show that their organ heart may completely stop because of how much pressure is required for swimming. Long story short— Yeah, no, don’t put the octopus down for cardio. They would much rather chill in their dens until it’s time to eat 😎 #Relatable If ya read this far, share this walktopus to your timeline to cephalobrate day 4 of #OCTOpusMonth! 🏷 #science #nature #biology #reef #underwater #diving #sea #biodiversity #ocean #animals #fish #octopus #natgeo #nationalgeographic #natgeoyourshot #STEM #scuba #scubadiving #underwaterphotography #wildlifephotography #myoctopusteacher #Eyes #eye #love #heart

Posted by Octonation – The Largest Octopus Fan Club on Monday, October 4, 2021
By: Manta Dive Gili Trawangan

Are there any hard parts on an octopus? 

YES, but they aren’t bones!

Octopuses have a hard beak, surrounded by muscles called a buccal mass which they use to crush their food. It is primarily made from chitin (lobsters and crab exoskeletons are made of the same thing!), and it’s similar to the cartilage that makes up our fingernails.

A study of Humboldt squid beaks found they contain 4 key elements: 

  1. Water
  2. Proteins
  3. Chitin
  4. Dark pigment

The base of the beak is mostly made of water, with levels of protein increasing near the stabbing beak end, making it the stiffest portion of the beak.

Makes sense, right?! 

You would want the part of your mouth meant to shred crab meat fish flesh and crack into clam/crab shells to be the toughest.

do octopus have bones? coconut octopus in a clam shell
Coconut Octopus in a clam shell

With no bones to leave behind, are there any octopus fossils? 

Again, the answer is YES!

Soft tissue does not preserve well, so the cephalopod fossil record is primarily made up of ancestors who had external shells like the ammonites and nautiloids (the nautilus is the only living relative from that group!). 

While squid and cuttlefish still have internal shells, many octopuses have lost theirs completely, which makes finding fossils of them incredibly unique!

The latest octopus fossil found!

Just recently, a 330-million-year-old, well-preserved TEN-armed octopus fossil was found in Montana. This exciting discovery pushed back the time frame of when vampyropods (an ancient cephalopod group to which octopus belonged) appeared in the ocean by 82 MILLION years. 

This means octopuses were around BEFORE the dinosaurs!!! 

a–d Scale = 1 cm. a Complete body fossil. b–d Showing arm crown; c arm traces in blue, purple indicates the arm is overlapping below two other arms, green indicates the arm is overlapping above itself; d red and yellow circles mark individual suckers. e–g scale = 5 mm; closeup of arms showing suckers, select suckers indicated with white arrows.

We know they’ve been planning world domination for a while, but maybe they’re closer than we realize! It’s so impressive because the last fossilized octopus was found in 1982 in France and was ‘only’ 165-million-year-old.

This fossil is also the first vampyropod fossil that has 10 arms instead of the usual 8 that we see in today’s octopus. 

graph of 10 arm first vampyropod fossil
By: Christopher D. Whalen & Neil H. Landman 

I know what you’re thinking… wouldn’t they be related to squid then? Not necessarily – if you consider our elusive vampire squid who falls within the vampyropod group and has 8 arms AND 2 filaments they use for feeding. 

Note: Check out this post to find out more about all the cephalopod tentacle and arm configurations! 

Idealized drawing of vampyropod gladius (based on Vampyroteuthis)
Idealized drawing of vampyropod gladius (based on Vampyroteuthis)

So… do octopus have bones? 

Bones aren’t the only shape creator in town! Depending on where you live and what you do, bones can be a completely overrated and unnecessary body part.

If you want to educate yourself some more about all sorts of different cephalopods, take a look at our encyclopedia. Or, what we call it, our Octopedia!

Connect with other octopus lovers via the OctoNation Facebook group, OctopusFanClub.com! Make sure to follow us on Facebook and Instagram to keep up to date with the conservation, education, and ongoing research of cephalopods.

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