40+ Jellyfish Facts For Kids That Are Crazy Tenta-Cool

Hannah Bowyer
Feb 21, 2024 By Hannah Bowyer
Originally Published on Dec 03, 2020
Family cooking together
Age: 0-99
Read time: 6.9 Min

Jellyfish, while sometimes very scary, are also one of the coolest and most unique animals on our planet.

We've put together this list of fascinating facts that will leave you wanting to tell all of your friends about these strange creatures. From jellyfish with an immortal life cycle to jellyfish being blasted into space, these jellyfish facts for kids will blow you away.

If you like our list of jellyfish facts and want more fun animal facts, check out our shark facts and chihuahua facts.

Interesting Facts About Jellyfish For Kids

These fun facts about jellyfish are all you need to know about jellyfish and their crazy history on Earth.

1. Jellyfish aren't fish at all. These mysterious creatures are actually gelatinous invertebrates, which means they have no spine and are like jelly!

2. There could be over 300,000 species of jellyfish out there that we don't know about yet. Across the world so far, we have discovered over 2000 different types of jellyfish, but scientists think that there are many more living in our oceans.

3. A group of jellyfish can be called a bloom, a swarm or a smack. We like smack the best because we imagine that's exactly what it would feel like if you came across a group of jellyfish and their nasty stingers! Blooms can have just a few jellyfish or thousands in them.

4. Jellyfish are older than dinosaurs! There are fossils from over 500 million years ago, and scientists believe that they might have even been around for 700 million years, making them hundreds of million years older than dinosaurs.

5. There are more than 25 types of jellyfish that humans can eat and they are very commonly eaten in places like China, Korea, Indonesia, Thailand, Myanmar, and The Philippines.

6. Another name for a jellyfish is a Medusa. This is because their round shape and tentacles look like Medusa from Greek mythology, who had snakes for hair.

Facts About Jellyfish Biology

From wild jellyfish characteristics and jellyfish food to the parts of a jellyfish and jellyfish colors, we've got the coolest biology facts you need to know.

7. Baby jellyfish are called 'ephyrae'. The jellyfish life cycle starts from an egg which turns into larvae, then into a polyp, and then into ephyrae before finally maturing into the medusa stage, which is the name for an adult jellyfish.

8. Jellyfish only sting other jellyfish species, because their stingers don't fire upon their own kind.

9. The main jellyfish parts of these fully grown animals are the bell-shaped body, the oral arms that bring their food to their mouth, and up to 15 tentacles.

10. Jellyfish can be made of anywhere between 85% and 98% water, so if you ever see one washed up on the beach they will almost start to vanish as their water dries up.

11. Jellyfish don't have a brain, a heart or lungs! As important as these organs are to us, jellyfish can survive without them. As they can absorb oxygen through their very thin skin, they don't need lungs. Jellyfish also don't have any use for a heart, because they have no blood, and instead of a brain, jellyfish have a set of nerves that let them move.

12. Most jellyfish species only live for less than a year and some only live for a couple of days.

13. Jellyfish are most closely related to corals and sea anemones and they are a part the same animal group.

14. Some jellyfish have crazy long tentacles. The largest jellyfish in the world, called the lion's mane has tentacles that can reach the same length as a blue whale, at 120ft long! Some jellyfish tentacles can be as short as 0.20 inches.

15. Jellyfish are a type of plankton, which comes from the Greek word meaning "to drift". Their movement depends on the direction of ocean currents as they can't swim very well.

16. No matter how long their tentacles are, jellyfish don't often get tangled with each other because they are so slippery. If they ever do lose a tentacle, many can easily grow them back.

17. Some species of jellyfish are bioluminescent, meaning they glow with bright colors in the dark. This is used to scare off predators, but it is also very pretty to look at.

18. Jellyfish have to poop out their food in the same place where they eat because they can't float if the food is still in their bodies.

19. The diet of a jellyfish includes crabs, fish, shrimp, plants, and sometimes even smaller jellyfish.

20. Some jellyfish actually have "teeth" that are very thin hairs that they use to pull and chomp up their food.

21. Jellyfish can use their mouth to move around the water by squirting a stream of water from it.

Little baby girl is cooking

Facts About Jellyfish Habitats

Here's everything you need to know about where and how jellyfish live.

22. There are hundreds of jellyfish species in every single ocean all over the world.

23. Most jellyfish live along coastal areas, but some live deep in the ocean or even in the freezing Arctic waters.

24. Most blooms form in the saltier areas of the ocean.

25. No "true" jellyfish species live in freshwater.

26. Pollution from things like oil spills are very harmful to jellyfish as the chemicals get absorbed into their skin and this can stop them from having babies and shorten their life.

27. A super unique jellyfish characteristic is that while most marine animals struggle to survive in our warming oceans, the easy adaptation of jellyfish to heat means they can survive.

28. Blooms usually form where ocean currents meet and if there a strong winds, hundreds or even thousands of jellyfish can end up on the beach. Jellyfish can also be found travelling alone.

Jellyfish Facts You Won't Believe

These wild jellyfish facts will leave you shocked knowing that they are actually real!

29. There is an immortal jellyfish. These animals can go from being an adult jellyfish right back to being a polyp and start the life cycle again, so they can technically live forever!

30. 60,000 jellyfish have been sent to space.

31. In China, jellyfish are used as medicine. They are said to help with improving memory and heart issues.

32. Jellyfish have some pretty crazy names. Some of the coolest jellyfish names include fire jellies, cannonball jellyfish, Portuguese man-of-war, and even purple people eaters.

33. Sometimes little fish use jellyfish as hiding spots, as their stingers protect them from predators. Crabs also sometimes sit on top of jellyfish if they don't want to swim.

34. The famous tale about peeing on a jellyfish sting is actually a myth and can even end up causing more pain.

35. Even though many marine animals like sea turtles and sunfish eat jellyfish, jellyfish populations are growing so fast they're starting to take over the ocean!


Freaky Jellyfish Facts

These jellyfish fun facts are sure to freak you out and will make sure you stay as far away as possible from these crazy critters, but will also leave you amazed.

36. The Australian box jellyfish is the most venomous marine animal in the entire world and has the deadliest sting of all jellyfish! Different types of box jellyfish also live in warm waters along coasts all over the world, so watch out for those nasty jellies.

37. Irukandji jellyfish are the smallest jellyfish in the world and can be smaller than a penny. But don't be fooled by their size, they are one of the deadliest jellyfish on earth!

38. You can get stung by a jellyfish without touching their tentacles. This happens if they release little bits of their body into the sea that float around and touch your skin.

39. Most stings happen when humans accidentally brush by a jellyfish.

40. A jellyfish's tentacles can have millions of very small stinging cells. These stinging cells release toxin into a prey, so when a human brushes a jellyfish, it stings because these toxins are going into our skin!

Here at Kidadl, we have carefully created lots of interesting family-friendly facts for everyone to enjoy! If you liked our suggestions for jellyfish facts then why not take a look at these calico cat facts, or clownfish facts?

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Written by Hannah Bowyer

Bachelor of Communication specializing in Media Arts Production, Communication, and Media Studies

Hannah Bowyer picture

Hannah BowyerBachelor of Communication specializing in Media Arts Production, Communication, and Media Studies

A fitness enthusiast with a passion for helping people find their best selves, Hannah is a qualified personal trainer who is currently training to be a yoga instructor. She is also knowledgeable about mindfulness and meditation. Hannah has lived and worked in many different countries across Asia and the Americas over the last four years, and loves to write about her travels. Her dynamic nature is reflected in her love for running, whether it's towards a plane or a personal best.

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