Jellyfish Explained

Jellyfish Explained! From the Box Jellyfish to Portuguese Man O’ War these sea jellies have some great special skills

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#13. Jellyfish are the oldest multicellular
When people think about the oldest organisms ever, their minds typically drift towards dinosaurs. However, there are several other organisms alive today that predate dinosaurs by many years.

#12. Jellyfish don’t have brains
The brain is one of the most important organs in the body of any complex organism. It is a key part of the central nervous system, responsible for coordinating all other major systems like the cardiac system, endocrine system, and digestive system.

#11. Jellyfish can clone themselves
Regeneration is an ability that some animals possess and others don’t, and all to varying degrees. A dolphin with a wound on its skin can regenerate it without leaving a scar. A lizard with a severed tail can grow a new one. When it comes to jellyfish, though, their regenerative abilities are next level.

#10. Jellyfish are mostly composed of water
When it comes to the composition of jellyfish, there really isn’t much to them. Humans may be composed of 70 percent of water, but for jellyfish, the figure is much higher. Jellyfish are composed of between 85 percent to 98 percent water. And so, if a jellyfish washes up on a beach, chances are, within hours, they will get completely dried up, leaving very little behind.

#9. Jellyfish can get as big as blue whales
There are over 200 species of jellyfish in existence. Although they have the same general appearance, these species sometimes vary widely from each other in terms of size, color, and so on.

#8. Some species of jellyfish are really venomous
Certain species of jellyfish have venom. This allows them to kill prey as well as protect themselves from predators. One of the most dangerous species of jellyfish to exist is the box jellyfish. The box jellyfish has venom which is so potent that it can kill 50 people.

#7. Some jellyfish species are immortal
There are certain species of jellyfish that could live forever if they were not killed by predators or interfered with by human beings. One of these species is known as Turritopsis dohrnii jellyfish.

#6. Jellyfish have traveled into space
To prepare for mankind’s interstellar future, space agencies such as NASA, ESA, and JAXA have been performing experiments with Earth life in space for decades now. One of those such experiments, performed by NASA, happened when they took a couple of jellyfish up in space in 1991.

#5. Jellyfish reproduce quite rapidly
Most creatures, due to the harmful activities of man, have declining populations. Jellyfish, on the other hand, are experiencing a population boom. So much so that they are beginning to cause disruption and are making scientists really worried.

#4. Jellyfish are not really fish
This might come as a surprise to most people, given their name. However, jellyfish are not really fish. This should be obvious from their appearance, as they look quite different from most other organisms we call fish. In reality, jellyfish are classified as gelatinous zooplankton.

#3. The jellyfish lifecycle has two distinct stages
The lifecycle of a jellyfish has five main stages. However, two of those stages are quite visually distinct from each other. The five main stages are Planula, Polyp, Strobila, Ephyra, and Medusa. Of those five stages, the two which are most visually distinct from each other are the adult stage or the medusa and the polyps or the young jellyfish.

#2. Some jellyfish have teeth
If you ever wondered if jellyfish have teeth, the answer is yes. However, this doesn’t apply to all species. Also, their teeth are far different than human teeth or even shark teeth. One jellyfish species that is known for having teeth is the beroid comb jellyfish.

#1. They are bioluminescent
It is estimated that over 50% of jellyfish species are bioluminescent. This means they have the ability to emit brilliant displays of light from their tissues. Bioluminescence can have many uses, depending on the organism. In some organisms, it’s used to attract prey. In other organisms, it’s used to attract mates. However, where jellyfish are concerned bioluminescence is mostly used to ward off predators and this manifests itself in different ways based on the species. For example, jellyfish such as comb jellies produce bright flashes to startle a predator and then make their escape. However, other species such as siphonophores can produce a chain of light or release thousands of glowing particles into the water as a mimic of small plankton to confuse the predator. And then, some other species can also produce glowing goo which they can stick to predators so as to confuse them.