Jellyfish are among the strangest and most fascinating creatures on planet Earth. With their otherworldly appearance and alien-like behaviors, these mysterious ocean animals often leave people wondering if they’re truly from this world.
Scientists and marine enthusiasts alike are captivated, sometimes baffled, by the unusual biological processes jellyfish undergo, which are unlike anything seen in most other animals.
In this article, we’ll explore 15 incredible and fun facts about jellyfish that reveal their bizarre anatomy, unique survival strategies, and surprising abilities. So, get ready to dive deep into their weird and wonderful world.
1. How Do Jellyfish Clone Themselves Naturally? Detailed Explanation of Strobilation
If you thought we were joking about the cloning part, you'd be incredibly wrong. And no, you aren’t in a sci-fi movie where there are interplanetary lasers and warships. Jellyfish can indeed clone themselves "NATURALLY."
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| Jellyfish Cloning Process Diagram Showing the Polyp Stage and Strobilation |
They do this in a teenage-like form known as the polyp stage. When a polyp reaches a particular level of maturity, it can begin splitting segments of its body off, resulting in the development of a new jellyfish that lives distinctly from the original. The process is called strobilation.
What a peculiar way to reproduce. Imagine if your fingers could create an entirely new human. From the movies we've seen, the idea of cloning never goes according to plan.
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Strobilation occurs when there's an increase in temperature, leading to warmer and more favorable environmental conditions for jellyfish. It involves the splitting of the polyp into segments called ephyrae; this leads to rapid population growth as one polyp can produce up to 15 segments. Strobilation occurs in only some cnidarians, particularly the ones belonging to the Scyphozoa class.
Read more about strobilation at Fiveable.
2. Why Do Jellyfish Have No Brains? Understanding Their Unique Nervous System
Just when you thought we’d go easy on you, here’s another bombshell: Jellyfish are one of the few animals to have no brains. That's right, jellyfish lack brains and perform every single task—from hunting for prey to reproduction—by feeling the world around them and responding accordingly with the help of a decentralized nervous system.
In an interview with PBS, Rebecca Helm, a researcher at Woods Hole Oceanographic Institute, gave insight into how these animals function without brains. She said,
Jellies are like the original computer networks, with little servers all along the margin of their body that they use cooperatively. They have a net of cooperative nerve bundles that talk to each other and some pockets of centralized nerves, but no master controller. That’s nice when, say, a sea turtle bites off part of the bell. That isn’t the end of everything, because jellyfish can lose some of those servers. It can function with, say, seven rhopalia rather than eight.
Read more at PBS.
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Without brains, jellyfish navigate the world with the help of a set of nerves called a nerve ring or nerve net. This nerve net enables them to detect sudden changes in the environment. So they can effectively feel when a temperature, gravity, salinity, current, or oxygen alteration occurs. Also, along their bells are nerve endings called rhopalia, which help them balance and sense light to coordinate their swimming.
Learn more about the jellyfish anatomy at the Ocean Conservancy.
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| Jellyfish Without A Brain |
3. Jellyfish Anatomy Explained: Why They Have No Heart
Do you think jellyfish having no brain is strange? Wait until you learn they also have no heart! These alien-like sea creatures defy typical anatomy by surviving without a heart. Instead, they rely on their unique epidermis to efficiently absorb oxygen directly from the water and distribute it throughout their bodies. This remarkable adaptation enables them to thrive in ocean environments without a circulatory system, unlike most animals.
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4. Why Do Jellyfish Have No Bones? Exploring Their Unique Boneless Anatomy
Wouldn’t it be weird if we named an animal jellyfish, and it had bones? Good thing no one thought about that.
Because they already have an epidermis that absorbs oxygen and helps maintain their structural integrity, jellyfish have never developed bones since they came into existence.
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Jellyfish have a hydrostatic skeleton, a type of skeleton controlled by fluid pressure, which in the marine animals' case is water. They can contract muscles arranged in a radial pattern within their bell to generate propulsion; this is how they move and maintain their shape.
Learn more about hydrostatic skeletons on Wikipedia.
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| Jellyfish Without Bones |
5. How Have Jellyfish Survived for Over 700 Million Years? A Look at Their Ancient History
Imagine a creature that never had bones, a heart, or a brain for 700 million years. Unfeasible, right? In the case of jellyfish, you'd be wrong. According to scientists, jellyfish existed as early as 700 million years ago.
Fossil evidence shows they were already on Earth over 505 million years ago; this means they existed more than 250 million years before the dinosaurs.
In a new research titled "Chromosomal Comparisons Reveal Omb Jellies As The Sister Group To All Other Animals," a group of researchers determined that the first animal on Earth was likely a comb jelly as when they compared the chromosomes of ctenophores (another name for comb jellies) and non-animals, they discovered both shared some gene chromosome combinations.
Daniel Rokhsar, a co-author of the research study and UC Berkeley professor, said,
The most recent common ancestor of all animals probably lived 600 or 700 million years ago. It's hard to know what they were like because they were soft-bodied animals and didn't leave a direct fossil record, but we can use comparisons across living animals to learn about our common ancestors.
Read more about the study on Nature's Site.
How many catastrophes do you think jellyfish survived? Give a guess in the comments.
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In the scientific sphere, the term non-animal refers to any research method that doesn't directly involve using animals; these include techniques like computer modeling, tissue studies, cell culturing, and non-invasive diagnostic imaging.
6. What Are Jellyfish Made Of? Exploring Their 95% Water Composition
Don’t tell me you thought jellyfish were made of jelly. Besides having a 95% water makeup, you may be wondering what the other 5% of jellies are. Well, muscles, nerve cells, and proteins that enable them to respond to stimuli, move, eat, and reproduce. So, in essence, they're like floating glass animals.
7. Meet the Lion’s Mane: The Largest Jellyfish Species Ever Discovered
Though they have some of the weirdest anatomy, like having no brains, hearts, and bones, jellyfish can get even more bizarre with humongous sizes that defy logic. The lion’s mane jellyfish is the largest known jellyfish species. It can reach a whopping length of 210 centimeters (7 feet) and with tentacles three times longer than a school bus at 36 meters (120 feet).
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A lion's mane jellyfish can have up to 1200 tentacles, and the largest ever recorded reached a length of 120 feet (36.5 meters). For more context, a blue whale, the largest animal on the planet, reaches a length of only about 100 feet, meaning lion's mane jellyfish can be longer than blue whales.
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| A Lion's Mane Jellyfish |
8. The Smallest Jellyfish Species: Tiny Ocean Creatures with Atomic Powers
You’ve learned about the behemoth, but do you know that jellyfish can be almost microscopic? That’s right, the peculiar creeping jellyfish is the smallest known jellyfish species.
Its bell disk can be as small as 0.5 millimeters and is only visible with a microscope or lens. Another unusual thing about the peculiar creeping jellyfish is their remarkable cloning ability through fission. It’s only fair for a microscopic organism to have atomic powers, right?
9. How Do Box Jellyfish See with 24 Eyes but No Brain?
Imagine having 24 eyes and no brain. That doesn’t sound possible because how could a living organism control its response to light if there’s no brain? Luckily, there’s one organism in that situation.
Box jellyfish are famous for their unique visual anatomy. They have 24 eyes that work in unison. Two can detect colors, while four can process visual information in parallel, giving them a 360-degree vision.
The first discovery of the 24-eyed box jelly was made by scientists at Hong Kong Baptist University (HKBU) in the Mai Po Nature Reserve in 2022. Professor Qiu, the leading scientist of the research team, stated,
We named the new species Tripedalia maipoensis to reflect its type locality-where the new species was first found. Although it is currently known only in Mai Po, we believe that this species is also distributed in the adjacent waters of the Pearl River Estuary as the gei wais are connected to the estuary through a tidal channel.
Read more about the discovery at NDTV.
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Box jellyfish process visual information using a specialized nerve cluster called rhopalia, which houses their 24 eyes. While some of these eyes detect simple light and shadow, others, such as the upper and lower lens eyes, can form detailed images, allowing the jellyfish to navigate and respond to their environment despite lacking a brain.
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| A Box Jellyfish — Credit |
10. Why Are Jellyfish Some of the Most Energy-Efficient Swimmers in the Ocean?
Imagine having no brain and still outperforming creatures with large fins at swimming. That’s how good jellyfish are at sea. They are so efficient that they use about 50% less energy than most ocean animals, like whales, sharks, and dolphins. With their efficiency, they travel farther than other creatures, about 80% more, on the same energy. That’s amazing.
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Jellyfish are efficient at swimming due to their hydrostatic skeleton. The minimal contraction of the muscles in their bell gives rise to a propulsion force that pushes them; this is done with little effort, resulting in less energy use.
11. Can Jellyfish Live Forever? Facts About the Immortal Jellyfish and Its Unique Life Cycle
Just when you thought it couldn’t get weirder, it does. Some jellyfish, like the Turritopsis dohrnii (immortal jellyfish), are virtually immortal. They can live forever because of their unique ability to reverse their developmental process.
The immortal jellyfish can devolve from an adult to a lower, sexually immature stage, and it can do this for as long as it wants. The only causes of death for the immortal jellyfish are predators, disease, and accidents.
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In a study titled "Comparative Genomics Of Mortal And Immortal Cnidarians Unveils Novel Keys Behind Rejuvenation," researchers mapped the genetic sequence of Turritopsis dohrni (immortal jellyfish) and discovered the molecular mechanisms behind its replication, DNA repair, telomere maintenance, redox environment, stem cell population, and intercellular communication. This could lead to future improvements in anti-aging remedies and one day result in a cure for aging itself.
Read more about the study in the Proceedings of the National Academy of Sciences, PNAS.
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| An Image of Turritopsis dohrnii (Immortal Jelly) |
12. Do Humans Eat Jellyfish? Surprising Facts About Jellyfish as Edible Seafood
When you thought humans couldn’t possibly find a way to add jellyfish into their diet, they'd utterly surprise you. In some parts of the world, like Asia and the United States, jellyfish are delicacies. It makes you wonder what the first person who caught, cooked, and ate a jellyfish was thinking.
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Sesame jellyfish salad is a popular seafood delicacy enjoyed around the world. In addition, many other delicious jellyfish dishes and culinary variants are prepared in various cultures, highlighting the versatility of this unique marine ingredient.
Here's a guide on how to make Sesame jellyfish salad at AllRecipes.
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| A Jellyfish Salad Delicacy |
13. Are Jellyfish Poisonous? What You Need to Know About Jellyfish Stings and Safety Tips
Most jellyfish can unleash a painful sting on anyone close enough; this is even scarier because their tentacles can be virtually invincible inside the water.
However, it can be worse as some, particularly box jellyfish, are so dangerous that they are ranked the number one most venomous animals in the ocean. So, it’s best to read signs warning about dangerous jellyfish and avoid them.
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To ease a jellyfish sting, first remove the tentacles with a glove or tweezers. Then, soak the affected area in hot water that's about 110 to 113 degrees Fahrenheit (43 to 45 degrees Celsius) until the pain eases. Under no circumstances should you rinse the area with cold fresh water or urine.
To learn more about treating stings, check out Mayo Clinic.
14. What Causes Jellyfish Blooms? Environmental Impact and Effects on Marine Life
Jellyfish blooms are sudden spikes in the marine creatures' population due to immensely favorable conditions; these blooms can severely impact the environment. Some blooms in Japan can reach up to 500 million, with each animal having massive lengths of 6.5 feet.
Also, if you’ve ever been curious about jellyfish, you must have wondered what a group is called. Besides bloom, the terms "swarm" and "smack" can refer to a group of jellyfish.
15. How Jellyfish Inspire Science and Medicine: Biomimicry and Future Research Breakthroughs
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| Jallies Glowing In the Dark — Credit |
Jellyfish have become a source of inspiration in science and medicine through the field of biomimicry, where researchers study their unique biology to develop innovative technologies.
Their transparent, flexible bodies inspire advances in soft robotics, while their bioluminescence is used in medical imaging and genetic research. Scientists are also exploring jellyfish’s efficient movement to design energy-saving underwater drones. These remarkable creatures continue to unlock breakthroughs that could revolutionize healthcare, engineering, and environmental monitoring.
Conclusion
Jellyfish are among the ocean’s strangest and most mysterious creatures, with abilities that seem almost alien, like cloning, living without brains or hearts, and even cheating death.
Whether you’re fascinated by their ancient survival story or surprised to learn they’re a food delicacy in some cultures, jellyfish never fail to amaze.
Which jellyfish fact blew your mind the most? Share your thoughts in the comments below, spread the word by sharing this article, and dive deeper into more bizarre animal facts on Biobizarre, like our popular 15 Evil Dolphin Facts.
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