There is a lot of confusion about jellyfish and creatures with jelly-like bodies. While the marine animals commonly referred to by the name jellyfish are part of the phylum Cnidaria, that has around 10,000 different types of jellyfish, there are others that belong to the family of creatures known as phylum Ctenophora.
Whatever family of species they belong to, jellyfish are some of the most mesmerizing and colorful creatures you will come across in the deep blues of our planet.
Top 15 Facts about Jellyfish
While you may undoubtedly know what a jellyfish looks like, we’ve put together some jellyfish facts for any fanatic. If you love jellyfish as much as we do, make sure you check out our top jellyfish gifts for jelly lovers!
There are more to these fascinating undersea dwellers than you probably realize. To illustrate this point, we are going to look at 15 particularly interesting facts.
1. They Don’t Have Organs
Jellyfish do not have any of the organs you’d normally find in animals. They don’t have stomachs, intestines or even lungs. Their internal system is much simpler than other creatures.
Jellies have bodies that comprise two different layers of cells, the internal gastrodermis and the external epidermis. They eat food, get rid of waste products and procreate using an opening in the gastrodermis. While they take in nutrients and oxygen through both the inner gastrodermis walls and through the external epidermis too.
2. They Are Made Of 95% Water
From their appearance, you’d probably assume there wasn’t much to jellyfish, structurally. And with closer inspection you’d realize you were right.
As they are around 95% water. What is the other 5%? Proteins and minerals. In-between their two basic layers, as outlined above, there is a watery, gelatinous material known as mesoglea which contains important proteins, nerve cells and muscle cells.
3. Not All Are Small…
There are a wide variety of jellyfish species out there and not all of them are the small critters you must swerve past when you are wading or swimming down by the beach. Take the lion’s mane jellyfish, for example, which has 50-meters long tentacles and a body with a possible diameter of as big as 6-meters.
By comparison, the aptly named Common Kingslayer is the smaller and is not even as big as a fingernail. However, don’t let its diminutive stature fool you as its categorized as being one of the most venomous critters on the planet.
4. They Can Sting You Even When They’re Dead
As gruesome and as unnerving as it is, it’s also true. Jellyfish often can, even when they are dead, sting you. An example of this when around 150 people were stung on a New Hampshire beach by the tentacles (that were separated from the body) of a lion’s mane jellyfish that had perished.
5. A Smack is the Name Given to a Group of Jellyfish
Unfortunately, the more accepted term for a group of jellyfish these days, though, is a swarm. In the past they were called a smack.
6. Many Jellyfish Are Edible
Despite their poisonous tentacles and venomous nature, there are many jellyfish that are edible. Not just for seat turtles or bigger jellies, either. In Korea and Japan, for instance, they are a real foodie treat. Japanese jellyfish have been made into candies.
7. Jellyfish Reproduce Both With and Without Sex
By releasing eggs and sperm into the water, jellyfish reproduce tiny, swimming larvae. Interestingly, though, they then grow into what are known as polyps and attach themselves to smooth surfaces and split up into lots and lots of young fully formed jellyfish. Which essentially means they reproduced asexually.
8. Some Have Fully Functioning Eyes
As we’ve already discussed, jellyfish are, by far, one of the simplest animals in terms of their body design and makeup. However, there are a few species out there that have working eyes.
Not only that, the way their vision works is rather sophisticated. The box jellyfish, for example, 24 of what could loosely be called eyes. Two of them allow the creature to see in color.
Even more startling, thanks to the 24 eyes and their placing around their body, this is one of a small number of animals able to view the world around them in 360-degrees.
9. Fish by Name, Not By Design
Although they are commonly referred to by the jellyfish moniker, they aren’t considered to be fish. This is because fish are water-dwelling animals who breathe using gills and are vertebrates. Whereas jellyfish absorb oxygen into their membranes and have no backbone.
10. They Survive, Live and Even Thrive in All Oceans
Jellyfish by their nature follow ocean currents, so they are found in all ocean water throughout the world, whether it’s those with tropical or extremely cold temperatures.
11. Many Jellyfish Glow
There are some jellyfish that are bioluminescent, which means they emit their own source of light. The light they produce can help them in various ways from distracting predators to attracting their prey. Speaking of prey…
12. Jellyfish Are Not Particularly Fussy
When it comes to food, jellyfish generally eat a diet of fish, shrimp and small plants using their tentacles in the way you probably imagine – to sting their prey to make them easier to eat.
13. There Are Some Jellyfish considered to be Basically Immortal
One species of jellyfish, Turritopsis dohrnii, is immortal as it can reset itself and turn into a huge colony of polyps. As one grows older and settles on the seabed, it transforms into polyps.
14. More Than 60,000 Jellyfish Went to Space
Have you gone to space? If you have, then you have that in common with more than 2,000 polyps. In 1991, they were sent to space as an experiment to see what would happen to them without gravity.
Sadly, although they managed to reproduce in outer space, making more than 60,000 new jellyfish, they did not function healthily when they came back home.
15. Some Are Not Equipped With Tentacles
It may be their most distinctive feature, but there are jellyfish who don’t have any tentacles. Scyphomedusa deepstaria can catch prey without tentacles.