9 Unknown Characteristics of Jellyfish

Sea creatures are always fascinating and full of intrigue. Among them, the jellyfish are some of the most mysterious, free-swimming marine creatures. Sometimes, they also stick themselves to rocks or other suitable places and stay immobile. A certain type of jellyfish is popularly called the “immortal jellyfish,” and it has got this name because of its regenerative characteristics. Scientists accidentally discovered the immortal jellyfish’s ability to live forever in the 1990s when they were studying this species in the Mediterranean Sea. So, let’s learn more about this immortal jellyfish!

Interesting Fact: Did you know that jellyfish lived thousands of years before the dinosaurs became extinct?

How Do Jellyfish Look?

1. They have a gelatinous body and are popular for their sting-filled tentacles. After the eggs of jellyfish are fertilized, they grow into tiny “larvae.” The larvae move around in the water until they find a hard surface to cling on to.

The larvae develop into “polyps,” which transform over time into young jellyfish. When these become adults, they are called “medusa.”

Habitat of Jellyfish

2. These creatures live in almost any part of the ocean. They usually swim in the water using their tentacles. They also make use of these tentacles to paralyze their prey, before gobbling it up.

You can find these creatures near the shorelines and also in deep waters. They thrive in hot as well as cold conditions, and can adapt themselves to their environment. 

How Long Do Jellyfish Live?

3. The common type of jellyfish in the wild live from a year to a year-and-a-half. However, in captivity, they live from 6 months up to a year. This shortened jellyfish lifespan is because the ideal conditions in the wild cannot be replicated in captivity.

Are Jellyfish Immortal?

4. All jellyfish are not immortal. However, the species, known as Turritopsis dohrnii, has a unique ability to avoid death for a long time.

It is said to reverse its life cycle, and hence the name, “immortal jellyfish.” It is 4.5 mm long. When the medusa of immortal jellyfish are under stress like starvation or a sudden temperature change, it does not die like other species. It just shrinks and retracts its tentacles. It stops moving in the water and attaches itself to a surface on the seafloor, thereby becoming a cyst-like creature.

The cyst then develops into a polyp, which is the previous life stage of the jellyfish. It begins its life cycle from the beginning, once again! Thus, the immortal jellyfish keeps on regenerating several times, until it is devoured by predators like crustaceans and sea slugs. This miraculous process of transformation is called “transdifferentiation.”

In transdifferentiation, the cells of the jellyfish will transform into a different cell type. For instance, the muscle cells of the jellyfish can transform into eggs or sperm cells, or the nerve cells can transform into muscle cells!

What Do Immortal Jellyfish Feed On?

5. The creatures are carnivores. Therefore, they depend on the following for food:

• Mollusks
• Fish eggs
• Zooplanktons
• Tiny sea creatures

However, some species of jellyfish feed on other smaller fish species, and animals like crab. They have a small opening through which they ingest food and eject their waste particles.

What Are Immortal Jellyfish Made Of?

6. Immortal jellyfish are mostly found in tropical waters, and they are said to have originated in the Pacific. But later, they spread to all parts of the world.

They are translucent sea beings that are made of 95% water. They are too tiny and don’t have the usual parts like brain, heart, or lungs that other animals possess. And yes, they lack blood too! These creatures don’t make good pets, so you can’t think of capturing one and taming it!

Can You Seem Them With Naked Eyes?

7. Yes, of course. You can see these species with your naked eyes. However, it’s easy to miss seeing them because they are too tiny, have translucent bodies, and move along with the water.

How Do They Protect Themselves?

8. Jellyfish protect themselves from their predators using their tentacles, which have stinging cells called “nematocysts.” Some of the predators of Turritopsis dohrnii are listed here:

• Sharks
• Sea anemones
• Swordfish
• Penguins
• Sea Turtles

How Many Tentacles Do They Have?

9. Immortal jellyfish use their tentacles to capture their prey. Whenever the animals come into contact with their prey, their stinging cells eject toxic substances that immediately paralyze the prey. Once the food is inside the jellyfish, it gets digested.

Some immortal jellyfish have only 8 tentacles, whereas others found in Japan and the Mediterranean Sea have 24 or more. These tentacles are powerful structures, using which the creatures move in the strong currents. Some scientists have even discovered immortal jellyfish that have 80 to 90 tentacles!

Aging in Reverse!

Immortal jellyfish are amazing creatures that age in reverse! They can cheat death several times, but many of them die because of predators or other survival challenges, before they repeat their life cycles. We hope you found this blog interesting as well as informative. To refresh your memory on the facts we have discussed, answer the Quiz on this page.