Facts about the animal kingdom

The Largest Jellyfish in the World

Josie F. Turner
By Josie F. Turner, Journalist specialized in Animal Welfare. Updated: May 12, 2020
The Largest Jellyfish in the World

Did you know that the largest animal in the world is a jellyfish? It is called Cyanea capillata but is commonly known as the lion's mane jellyfish. While we may think of jellyfish as being about the size of a dinner plate, this one is even longer than the blue whale. The largest known specimen was found in 1870 off the coast of Massachusetts. Its bell averaged 2.3 meters in diameter and its tentacles reached 36.5 meters in length.

This Animal Wised article on the largest jellyfish in the world will give you all the details about this gigantic inhabitant of our seas. We also provide the runners up in the list of the biggest jellyfish ever.

You may also be interested in: The Largest Insects in The World
  1. Lion¡s mane jellyfish
  2. Habitat of the lion's mane jellyfish
  3. Behaviour and reproduction of the lion's mane jellyfish
  4. Interesting facts about the world's largest jellyfish
  5. Biggest jellyfish in the world runners up

Lion¡s mane jellyfish

Its common name ofthe lion's mane jellyfish comes from its physical appearance and similarity to the hair around a lion's head. You can find other animals in its mane, such as shrimp, palometas or juvenile prowfish. They are immune to its venom and find it a good source of food and protection from other predators.

This jellyfish has eight clusters in which their tentacles are grouped. It is estimated that its tentacles can measure up to 60 meters long and they have a color pattern ranging from crimson or purple to yellow.

They feed on zooplankton, small fish and even other species of jellyfish that are caught between its tentacles. They inject their paralyzing venom through their stingers. This paralyzing effect facilitates the ingestion of prey.

The Largest Jellyfish in the World - Lion¡s mane jellyfish

Habitat of the lion's mane jellyfish

The lion's mane jellyfish lives mainly in the icy and deep waters of the Antarctic Ocean. This habitat extends to the North Atlantic and the North Sea, giving plenty of space for the world's biggest jellyfish to swim.

Few sightings have been made because this jellyfish inhabits the area known as the abyss that lies between 3000 and 6000 meters deep. It is very rare for them to approach coastal areas. They prefer the deeper regions of the ocean because they need cool spaces to live. The warmer coastal waters are often too warm for them to survive.

If the lion's mane jellyfish does appear in coastal regions, it is likely to be due to their poor swimming ability. One reason they stay in deep water is because they can become easily caught in a current and be unable to swim back to their usual home-

The Largest Jellyfish in the World - Habitat of the lion's mane jellyfish

Behaviour and reproduction of the lion's mane jellyfish

Like all other jellyfish, due to poor swimming ability, their movement depends directly on ocean currents. They limit themselves to vertical, and to a much lesser extent, horizontal movement. Because of these limitations in movement, it is impossible for them to chase things, so its tentacles are its only weapon to feed.

They breed in summer and autumn. Although they usually breed, they are known to be asexual. This means they can produce both eggs and sperm without the need for a partner. The mortality rate of this species is very high in the first days of life.

In most cases, a lion's mane jellyfish sting is not fatal for people even if it causes severe pain and rashes. In extreme cases, if a person was trapped in its tentacles, the large amount of poison absorbed that would be absorbed though the skin could be fatal. However, this would also depend on circumstances. It is possible someone will panic and drown. Also, those with pre-existing conditions such as heart problems may die as a secondary result.

Even after the jellyfish is dead, their tentacles can still sting you. In 2010, a dead jellyfish was found in Rye, New Hampshire. Due to its large size, the dead jellyfish managed to sting a whopping 150 people before being taken in[1].

The Largest Jellyfish in the World - Behaviour and reproduction of the lion's mane jellyfish

Interesting facts about the world's largest jellyfish

  • At The Deep Aquarium in Hull, England you can find the only example kept in captivity. It was donated to the aquarium by a fisherman who captured it on the east coast of Yorkshire. The jellyfish is 36 cm in diameter and is also the largest jellyfish kept in captivity[2].
  • Vinegar can be used to deactivate the sting of the jellyfish. However, it is recommended you seek medical attention just in case there are any other adverse effects.
  • Sir Arthur Conan Doyle was inspired by this jellyfish to write the story The Adventure of the Lion's Mane in his book The Case-Book of Sherlock Holmes.

If you want to know more fun facts, you can also take a look at our article on how jellyfish reproduce.

The Largest Jellyfish in the World - Interesting facts about the world's largest jellyfish

Biggest jellyfish in the world runners up

While the ion's mane jellyfish has the largest specimen ever recorded, there are many different types of jellyfish. The next largest jellyfish which can be found in the sea include:

  • Nomura’s jellyfish: although the largest recorded jellyfish in the world is the lion's mane jellyfish, the Nomura’s jellyfish is generally about the same size. You can often find nomura’s Jellyfish which are bigger than the lion's mane. Although not very tasty, they are sometimes eaten in parts of Asia and they also have envenomated tentacles. The toxins similarly are usually not fatal, but they are becoming more commonplace as they have had many population blooms in recent years.

  • Pink meanie jellyfish: while its taxonomic name is Drymonema larsoni, this big jellyfish is called the pink meanie due to its pink color and its habit of cannibalizing other jellyfish. They are relatively rare, but there have been more sightings in the past 20 years.

  • Stygiomedusa gigantea: the only known species in its taxonomic group, this jellyfish doesn't have tentacles in the same way as the other jellyfish in this list have. Instead they have four large flap-like ‘arms’ which can reach up to 30 m in length. There have been very few sightings over the centuries, so we know little about it's behavior. We only know, so far, that it is one of the biggest jellyfish in the world.

  • Black sea nettle: although it is pretty much the same size as the Pacific sea nettle, they both are in the same genus. Their bell (the non-tentacle body) can measure up to a meter in diameter. They are usually of a cold color and have very interesting tentacles. They even have tentacles at their mouth to help ingest prey. They usually live in very large groups, but are rarely seen.

If you enjoyed this article, you may be interested in our article on the types of sea turtles and how does mass coral bleaching affect the Great Barrier Reef?

If you want to read similar articles to The Largest Jellyfish in the World, we recommend you visit our Facts about the animal kingdom category.


1. Reino, R., & Cunningham Jr., J. (2010). Jellyfish stings 150: Wallis Sands scene in Rye a ‘real horror show’. https://www.fosters.com/article/20100722/GJNEWS_01/707229738

2. BBC. (2010). The Deep's Lion's Mane jellyfish 'largest in captivity'. https://www.bbc.com/news/uk-england-humber-10733328

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The Largest Jellyfish in the World