Have you ever wondered if a jellyfish is a fish? We certainly have. There are so many unexpected facts about these little blobs on the beach! When you start learning some jellyfish facts, you realize they are super cool creatures. So let’s dive in (pun intended!)
So what is a jellyfish, anyway? They have no brains, no bones, no blood and are made up of 95% water. Super weird!
Is a Jellyfish an Animal?
Webster’s dictionary says a jellyfish is “a free-swimming marine coelenterate that is the sexually reproducing form of a hydrozoan or scyphozoan.” Ok, so that’s a complicated definition, let’s break it down a bit.
So, is a jellyfish an animal or a plant if it doesn’t have a brain? They are carnivorous animals with no backbone. Okay, so they’re an invertebrate that eats other animals!
So they’re not fish? Nope! They belong to a group of animals called: cnidarians! Tricky word to say, it’s pronounced: nai-deh-ree-uhnz. This animal group has stinging cells that they use to catch prey and defend themselves. Other animals in this group are anemone and coral. Neat!
Fun Facts about Jellyfish
- Jellyfish are pretty weird, so it makes sense that they have a weird life cycle too! A jellyfish starts out as a polyp—a tiny, tube-like animal. This polyp then splits into multiple little juvenile (or baby) jellies called ephyrae. Last but not least, a jellyfish when it’s fully grown is called a medusa.
- Interestingly, jellyfish can also help protect small fish. Some fish hide in their tentacles or inside their bell (the body cavity) to stay safe from predators, using the jellyfish like a floating safehouse.
- Jellyfish have been drifting through the oceans for millions of years—long before dinosaurs existed. Want to guess how old jellyfish can live? Different species have different lifespans: most live a few years, some only a few days. But one special species, Turritopsis dohrnii, also known as the "immortal jellyfish," can potentially live forever! Instead of dying of old age, they revert back to their polyp stage and start their life cycle all over again. They're more likely to be eaten by a turtle than to die naturally. Pretty crazy!
What Jellyfish are Near Us?
There are about 8-12 species of jellyfish native to the NC coast! You might have heard of some before: moon jellies, purple sail, summer and winter sea walnut, squash jellyfish, sea nettles, cabbage head, mushroom jellyfish, and the lion’s mane jelly.
Do All Jellyfish Sting?
Not all jellyfish sting, but most do—it’s just the kind of animal they are!
Some jellyfish have stings powerful enough to seriously hurt people, ouch! But in most cases, their sting is relatively harmless. Take the moon jellies above for example, most people don’t even react to their sting. At the worst, people experience a slight itchiness or rash.
However, you do have to be very careful around certain species. Lion’s mane jellyfish can deliver painful stings that can be pretty dangerous.
Some creatures that look like jellyfish can sting even though they aren’t actually jellyfish. For example, the Portuguese man-o-war. It isn’t a jellyfish—but it sure packs a mean sting!
Jellyfish are a complicated fascinating group of animals. The absolute best rule to follow when you do see one? Avoid touching it!
Why Are Jellyfish Important?
If you love sea turtles, you’ll be happy to know that jellyfish are one of their favorite foods! You can read more about sea turtles on our page about them! Many ocean animals eat jellyfish, making them an important food source for predators higher up on the food chain. Because of this, jellyfish are considered “essential prey” in their ecosystems.
Interestingly, jellyfish have adapted well to climate change, pollution, and human activities. In fact, they are one of the few animals thriving in today’s changing ocean conditions.
Want to help jellyfish? You can become a citizen scientist! Check out our blog, Citizen Scientists, to learn how you can get involved.
