Skip to Content

Why Don’t Octopuses Have Bones? Octopus Science Experiment

If there is one thing that is a lot of fun to try when doing ocean science experiments, it is to learn about ocean creatures! Today, we are doing a fun octopus science experiment and learning why an octopus doesn’t have bones! This was a super fun part of our octopus STEM activities series.

This easy ocean science experiment will show kids what would happen if an octopus had bones.

Keep reading to get to the directions for this octopus experiment but first, learn a bit more about the octopus and make sure you have everything you need to do this experiment!

This easy octopus science experiment will answer the question do octopuses have bones? Includes a complete octopus STEM activity lesson plan!

Why Don’t Octopuses Have Bones?

Try this easy octopus science experiment to figure out if an octopus has bones, and if it doesn’t, why not?

But before starting the activity, take a few moments to learn a little bit about our deep ocean friends- the octopus!

What is An Octopus?

An octopus is a sea creature that has eight arms, round heads, and soft bodies. They are most often found in warm, tropical waters.

Octopuses are in the class Cephalopoda along with  squids, nautiloids. and cuttlefish.

STEM extension worksheets

How many eyes do octopus have?

An octopus has two eyes, one on each side of its head.

Despite living in the deep sea where light can be scarce, octopuses have excellent vision. They can detect both the direction and intensity of light, and they can also see in both dim light and bright light.

However, unlike humans, it is believed that octopuses may be colorblind because they have only one type of color receptor in their eyes, compared to humans who have three.

Does an octopus have bones?

We don’t know exactly why an octopus doesn’t have bones, except that it evolved that way.

Scientists believe that once, the octopus had a shell like sea snails and some other ocean creatures. But over time, it evolved away from having a shell.

Octopus Books for the Classroom

Here are some of our favorite non-fiction octopus books for kids to learn more fun facts about octopuses!

q? encoding=UTF8&ASIN=1682633128&Format= SL160 &ID=AsinImage&MarketPlace=US&ServiceVersion=20070822&WS=1&tag=schomonk 20&language=en USir?t=schomonk 20&language=en US&l=li2&o=1&a=1682633128q? encoding=UTF8&ASIN=B0C7F56XCP&Format= SL160 &ID=AsinImage&MarketPlace=US&ServiceVersion=20070822&WS=1&tag=schomonk 20&language=en USir?t=schomonk 20&language=en US&l=li2&o=1&a=B0C7F56XCPq? encoding=UTF8&ASIN=0544232704&Format= SL160 &ID=AsinImage&MarketPlace=US&ServiceVersion=20070822&WS=1&tag=schomonk 20&language=en USir?t=schomonk 20&language=en US&l=li2&o=1&a=0544232704
q? encoding=UTF8&ASIN=1644943972&Format= SL160 &ID=AsinImage&MarketPlace=US&ServiceVersion=20070822&WS=1&tag=schomonk 20&language=en USir?t=schomonk 20&language=en US&l=li2&o=1&a=1644943972q? encoding=UTF8&ASIN=B09YVR5CY3&Format= SL160 &ID=AsinImage&MarketPlace=US&ServiceVersion=20070822&WS=1&tag=schomonk 20&language=en USir?t=schomonk 20&language=en US&l=li2&o=1&a=B09YVR5CY3q? encoding=UTF8&ASIN=1426335024&Format= SL160 &ID=AsinImage&MarketPlace=US&ServiceVersion=20070822&WS=1&tag=schomonk 20&language=en USir?t=schomonk 20&language=en US&l=li2&o=1&a=1426335024
Click on each book cover to learn more and order for your students!

How many bones does an octopus have?

Octopuses do not have any bones at all!

As invertebrates, their bodies are completely soft, except for one part – their beak.

The beak, which is made of a material similar to a bird’s beak, is the only hard part of an octopus’s body. This beak is located in the center of their arms and is used to eat their prey.

The absence of bones allows octopuses to be highly flexible and able to squeeze through very small spaces, an ability which is useful for both hunting and evasion from predators.

Do octopus have cartilage?

Octopuses do not have any cartilage in their bodies.

They are invertebrates, which means they lack an internal skeleton. T

he only hard part of an octopus’s body is its beak. This is made of a tough material called chitin, which is the same material that crab shells are made of.

How small of a hole can an octopus fit through?

An octopus can fit through any hole that’s larger than its beak, which is the only hard, inflexible part of its body. This means that an octopus about the size of a football, could fit through a hole approximately the size of a quarter.

You may also like to do some of our other ocean science experiments.

Can an octopus fit in a jar?

For all but the largest octopuses, the answer is yes.

If you’re curious to see what type of octopuses can’t fit in a jar, here is a list of the largest octopus species in the world.

Here is a video of an octopus coming out of a jar!

Does an octopus make sound?

The human ear cannot hear any sound that an octopus makes.

Most of octopus communication occurs visually through changing colors, patterns, and body language.

However, some scientists believe that they may use sound to communicate in ways that we haven’t found out about yet!

Octopus STEM Kits

These octopus STEM kits teach kids how different parts of an octopus works and offer another fun hands-on octopus STEM activity for kids to learn about the amazing octopus!

clixo octopus
q? encoding=UTF8&ASIN=B07GRKGVNG&Format= SL250 &ID=AsinImage&MarketPlace=US&ServiceVersion=20070822&WS=1&tag=schomonk 20&language=en USir?t=schomonk 20&language=en US&l=li3&o=1&a=B07GRKGVNG
q? encoding=UTF8&ASIN=B08V8XXM41&Format= SL250 &ID=AsinImage&MarketPlace=US&ServiceVersion=20070822&WS=1&tag=schomonk 20&language=en USir?t=schomonk 20&language=en US&l=li3&o=1&a=B08V8XXM41q? encoding=UTF8&ASIN=B0B68567FQ&Format= SL250 &ID=AsinImage&MarketPlace=US&ServiceVersion=20070822&WS=1&tag=schomonk 20&language=en USir?t=schomonk 20&language=en US&l=li3&o=1&a=B0B68567FQ
Click on each image to learn more about the octopus STEM kit and order it for your students.

If you need even more extensions for your octopus STEM activities, check out these octopus lesson plans!

Octopus Science Experiment Lesson Plan

You can get the complete 17-page lesson plan and customized worksheets for this science experiment in the Jarring Science Club!

Click the image below to learn more and access the complete octopus lesson plan!

jsc optin

Octopus Science Experiment Hypothesis

Before getting starting with this experiment, kids should make a hypothesis on why they think an octopus has a soft body.

They should also make predictions on whether their octopus will be able to fit through a small hole with and without bones.

Octopus Experiment Supplies

Shop these Amazon affiliate links to get everything you need for this octopus science project!

STEM extension worksheets

How to Do the Octopus Science Experiment

To do this experiment, first cut a one-inch hole into the center of a paper plate. Position that over your jar.

Tape in place, if necessary.

Next, make your octopus model and test your variables!

Find out why an octopus doesn't have any bones in this easy octopus science experiment!

Variation 1: How to Make an Octopus Model

Draw your octopus body onto the plastic baggie with a permanent marker. You can freehand it, or use our included template.

Add about a tablespoon of instant snow powder to your baggie.

Fill the bag halfway with water. Add some food coloring.

If the bag is too liquidy, you can add a bit more instant snow powder.

octopus bag experiment

Seal the bag tightly and remove excess air.

Feed the octopus bag through the hole.

Octopus Shirts for Teachers

Check out these super fun octopus shirts you can wear during your octopus lessons!

octopi shirt
octopus teacher shirt ocean of possibilities
octopus shirt
octopus book shirt
cute octopus shirt
valentine octopus shirt
i wish i was an octopus shirt
cephalopods shirt
Click on each image to order your octopus teacher shirt!

More Octopus Activities for Kids

Octopus STEM Activities

O is for Octopus Letter Craft

Octopus Activity for Kids: LEGO Octopus

Paper plate octopus craft

octopus with bones octopus science project

Variation 2: Making an Octopus with Bones

Remove the octopus from the bag and add some toothpicks to the bag to represent bones. Try to feed the octopus through the hole again.

It’s much harder or even impossible with the bones!

Octopus Lesson Resources

Use these octopus classroom supplies and products to go along with your octopus STEM lessons!

q? encoding=UTF8&ASIN=B0C6PX8TP4&Format= SL160 &ID=AsinImage&MarketPlace=US&ServiceVersion=20070822&WS=1&tag=schomonk 20&language=en USir?t=schomonk 20&language=en US&l=li2&o=1&a=B0C6PX8TP4q? encoding=UTF8&ASIN=B07MCQP7BS&Format= SL160 &ID=AsinImage&MarketPlace=US&ServiceVersion=20070822&WS=1&tag=schomonk 20&language=en USir?t=schomonk 20&language=en US&l=li2&o=1&a=B07MCQP7BSq? encoding=UTF8&ASIN=B094V4X55Z&Format= SL160 &ID=AsinImage&MarketPlace=US&ServiceVersion=20070822&WS=1&tag=schomonk 20&language=en USir?t=schomonk 20&language=en US&l=li2&o=1&a=B094V4X55Zq? encoding=UTF8&ASIN=B09GF4ZKG5&Format= SL160 &ID=AsinImage&MarketPlace=US&ServiceVersion=20070822&WS=1&tag=schomonk 20&language=en USir?t=schomonk 20&language=en US&l=li2&o=1&a=B09GF4ZKG5
clixo octopus
diy paper octopus origami puzzle
octopus fidgets
q? encoding=UTF8&ASIN=B07BVYWTNN&Format= SL160 &ID=AsinImage&MarketPlace=US&ServiceVersion=20070822&WS=1&tag=schomonk 20&language=en USir?t=schomonk 20&language=en US&l=li2&o=1&a=B07BVYWTNNq? encoding=UTF8&ASIN=B0BTHJMKBW&Format= SL160 &ID=AsinImage&MarketPlace=US&ServiceVersion=20070822&WS=1&tag=schomonk 20&language=en USir?t=schomonk 20&language=en US&l=li2&o=1&a=B0BTHJMKBWq? encoding=UTF8&ASIN=B0BJBYX9VS&Format= SL160 &ID=AsinImage&MarketPlace=US&ServiceVersion=20070822&WS=1&tag=schomonk 20&language=en USir?t=schomonk 20&language=en US&l=li2&o=1&a=B0BJBYX9VSq? encoding=UTF8&ASIN=B08FGZL1GN&Format= SL160 &ID=AsinImage&MarketPlace=US&ServiceVersion=20070822&WS=1&tag=schomonk 20&language=en USir?t=schomonk 20&language=en US&l=li2&o=1&a=B08FGZL1GN
Click on each image to purchase these octopus supplies for your classroom!

If you need more inspiration for your octopus lessons, check out these octopus lesson plans!

Octopus Science Experiment Conclusion

We found that when we gave our octopus bones, it could no longer fit through a small hole. If an octopus had bones, it wouldn’t be nearly as flexible or versitile as it is in the wild.

This could cause the octopus to have a harder time finding food, and a harder time evading predators.

Share this project with a friend!

Shelly Sugarplum

Tuesday 12th of July 2022

I will be doing this experiment online and need to make some adjustments. First, what can I substitute for the snow? My students are in China and I need simple everyday supplies, I am sure they won't be able to get this craft supply. My second question is about the toothpick "bones", won't the toothpicks make holes in the bag? Would paper clips do the same thing? Thank you for sharing your awesome experiment!

Brenda MacArthur

Tuesday 29th of November 2022

Yes, you can use paperclips. You can use any thick liquid for the octopus. Hair gel or conditioner could be used.