Jellyfishes are renowned for their long tentacles and bells shaped like umbrellas. But jellyfishes are even more famed for their purported immortality. Is it true that jellyfishes never die? If not, how long do they live?
The lifespan of jellyfishes varies with the species, habitat, predator density, and sexual activity. Popular species like the Moon Jellyfish can live up more than one year and the polyp can live up to 25 years , while species like the Sea Wasp Jellyfish live only for a few weeks. That said, the Turritopsisdohrnii (famously known as the Immortal Jellyfish) can live for tens of thousands of years.
Jellyfishes have exciting lifecycles. But more than the lifespan, how long can a jellyfish survive out of water? How old is the longest-living jellyfish alive? What is the lifecycle of the famed Immortal Jellyfish?
We will authoritatively address these questions in this guide.
Different Types of Jellyfish Lifespan
As we said, the lifespan of jellyfishes largely depends on their species. Some species can last decades, while some don’t even survive up a day.
Let us look at some of the most recognized jellyfish species and their respective lifespans.
Upside-Down Jellyfish
Upside-down. Quite a curious name, isn’t it?
Well, that oddness in name can be traced to the exceptional behavior this jellyfish demonstrates.
While jellyfishes traditionally float with their bells up, the upside-down jellyfish floats through the water with its bell sitting on the ground. When it wants to intercept food, it pushes its tentacles up.
Large populations of the upside-down jellyfish are concentrated in tropical waters – specifically in the sheltered coastal areas.
The lifespan of an upside-down jellyfish in the wild is yet scientifically established. But an upside-down jellyfish in captivity can survive up to 4 years if appropriately catered for.
Lion’s Mane Jellyfish
Among the global jellyfish family, the Lion’s Mane is the largest. Do you know some lion’s mane jellyfishes even rival the blue whale in size?
Yes, some lion’s mane jellyfishes have been found to grow bells with diameters running into 2.13 m. Their tentacles could grow up to 34m in length.
These species derive their name from their enormous mane composition, with an estimated 1,200 tentacles bunched up in the mane. This species averagely live for a year.
Moon Jellyfish
If there were “celebrities” among the jellyfish family, the moon jellyfish would rightly count among them. Yes, they are that popular.
Aside from the Arctic Ocean, the Moon Jellyfish is clustered globally in coastal areas of oceans.
It is easy to pick out the moon jellyfish from a crowd of jellyfishes. Their bells are decked with peculiar half circles. These half-circles take on reproductive duties.
The moon jellyfish is further adored for its bioluminescence. When bumped in the dark, this jellyfish gives off a distinctive light purple flash.
Moon jellyfishes averagely live anywhere from 12 to 18 months. However, a moon jellyfish can survive two decades when adequately taken care of!
Sea Wasp Jellyfish
When you hear the word “wasp” in the name of this jellyfish, you immediately know you are coming across a brutal guy.
This is –by a distance – the biggest cubozoan jellyfish alive. Its tentacles alone can get longer than 3m. Its bell can get as big as 0.2m.
Suppose you were thinking why the wasp in its name, the sea wasp jellyfish has the most venomous sting among all jellyfishes. A sting from its tentacles can cause heart failure within minutes.
The sea wasp jellyfish rarely survives for up to a month. However, the sea wasp can live up to 12 months in extremely rare cases.
Immortal Jellyfish
This is one of the most exciting jellyfishes ever. As you can readily infer from the name, this jellyfish will outlive you!
This jellyfish thrives in the tropical to temperate water bodies. The immortal jellyfish has a unique life cycle that enables it to recreate itself and live again.
We will learn more about this shortly.
The Cannonball jellyfish lives between 3-6 months.
The flame jellyfish is another species worth mentioning. It rarely survives longer than 12 months. In most cases, it dies by its third month.
How Long Can Jellyfish Live Out of Water?
Jellyfishes are poorly equipped to survive terrestrial conditions. Water accounts for 95% of their body composition.
The jellyfish’s mesoglea is mostly water, nerve cells, and structural protein. Therefore, prolonged abstinence from aquatic conditions can kill them.
Specifically, a jellyfish can’t survive more than 60 minutes outside water.
Factors That Affect Your Pet Jellyfish Lifespan
Several parameters cumulatively determine how long a pet jellyfish will live. First, as we have seen, is their species.
Some jellyfishes are genetically programmed to live long while others die too shortly.
The environmental conditions of their habitat also matter. If a jellyfish can aptly source food and unpolluted water in the tank you keep it, it could live longer.
The density of predators where it stays also matters. if you are keeping your jellyfishes in regions with predators like turtles, grey triggerfish, and ocean sunfish, it will inevitably die quicker.
The sexual activity of the jellyfish also contributes. Jellyfishes with high sexual activity tend to die quicker.
How Old is the Oldest Jellyfish?
The crown for the oldest jellyfish goes to the Turritopsisdohrnii. This species is famously referred to as the immortal fish.
This species’ lifecycle is admittedly complex. Scientists have been unable to establish the age of the oldest jellyfish authoritatively.
That said, some immortal jellyfishes in the wild have been estimated to exist since the times of the dinosaurs!
How Long Can an Immortal Jellyfish Live up to?
The immortal jellyfish gained celebrity status as a natural wonder in the early 1980s.
Given that intense scientific investigation began on this species some decades ago, it is challenging to measure how long the immortal jellyfish can live.
What is proven is that the jellyfish ages backward. It can reproduce itself and start living again just when it is about to die.
Let us peer more into its incredible lifecycle.
Immortal Jellyfish Life Cycle
Here is the exciting stuff about the Immortal Jellyfish. Just about when the grim reaper (death) comes calling – say when the Immortal Jellyfish’s medusa is damaged either from starvation or stress – it shrinks into itself rather than die.
This way, the immortal jellyfish reabsorbs its tentacles. With its tentacles lost, it can’t swim anymore, causing it to fall down the seafloor.
Now on the seafloor in the form of a cyst (mirroring a blob), the immortal jellyfish grows from a blob within the next 36 hours into a brand-new polyp.
This process is called transdifferentiation and is painstakingly scarce to come across in living things. This way, the jellyfish regrows itself with a new body maturing again.
This process can be repeated hundreds of times, meaning unless eaten by predators, the immortal jellyfish can practically live forever if the conditions are perfect.