Cyanea capillata, commonly known as Lion’s mane Jellyfish is among the biggest jellyfish species ever identified. It’s very scientific name is a hybrid between Greek and Latin which translates into “Blueish green” and “Long hair,” referencing its incredibly long tentacles. The term also makes a reference to the very dense and long tentacles that most closely resemble the mane of a male lion.

The Lion’s mane Jellyfish is by far the largest jellyfish in the ocean, reaching lengths of up to 120 ft with a bell of up to 8ft wide, inhabiting the colder waters of the ocean.

Let’s take a look at Lion’s mane jellyfish, how to identify it, where it can be found, and all about its common habits.

Lion’s Mane Jellyfish Taxonomy

  • Kingdom: Animalia
  • Phylum: Cnidaria
  • Class: Scyphozoa 
  • Order: Semaeostomeae 
  • Family: Cyaneidae
  • Genus: Cyanea
  • Species: Cyanea capillata
The Lion's mane jellyfish is the largest jellyfish species
The Lion’s mane jellyfish is the largest jellyfish species

Lion’s Mane Jellyfish Summary

SpeciesCyanea capillata
Common nameLion’s mane jellyfish
Bell size8ft (2.4m)
Tentacle length120 ft (36.5m)
HabitatNorthern Atlantic, Pacific, and Arctic Oceans
DietFish larvae, fish eggs,  crustaceans, small fish, and other jellyfish
PredatorsSea turtles, birds, and other jellyfish
ReproductionBoth sexual and asexual
Potential threatProduces a painful sting that can cause allergic reactions and, in rare cases, death
Lion’s Mane Jellyfish Quick Facts


The Lion’s mane jellyfish is easily distinguishable thanks to its giant bell and shockingly long tentacles that represent the shape and color of a lion’s mane.

The bell of Lion’s mane jelly can grow over 2 meters in diameter. The bell is commonly found in yellowish-brown or red-brown color. The tentacles are slightly lighter than the bell, looking almost golden.

These tentacles can reach massive lengths, and it’s not uncommon for them to be more than 30 meters long. These tentacles are covered in thousands of stinging cells, which are used for protection and feeding.

Coming out of the base of the jelly are 8 arms, also known as divots, which are used to transport food from the tentacles to the jelly’s mouth. Sensory organs such as fragrance holes, balancing organs, and light detectors can be found along them.

Lion’s mane jellyfish are bilaterally symmetrical and are made up of approximately 94% water. Given the fact it possesses 2 cellular layers, it is diploblastic.

The bell of Lion's mane jellyfish is separated into 8 noticeable segments by 8 divots with other indentations
The bell of Lion’s mane jellyfish is separated into eight noticeable segments by eight divots with other indentations

Every lobe has a balancing organ within intervals among its columns of tentacles, which vary in quantity from 70-150. Its mouth, which is located in the middle of the lobes, houses the oral limbs. They are embroidered and stuffed with nematodes, which are irritating cells that jellyfish utilize to paralyze their victims.


Lion’s mane jellyfish are known as opportunistic feeders, meaning they feed on what comes to them instead of seeking out and actively hunting their prey.

Lion’s mane jellyfish commonly feed on but are not limited to:

  • Small crustaceans
  • Fish larvae
  • Fish eggs
  • Tiny fish
  • Smaller jellyfish
  • Ctenophores
  • Plankton
  • Crabs

Because of their bioluminescence, members of this species can illuminate at night. They can capture such small prey by luring them close enough so that they can extend out and seize them with their other adhesive tendrils and venomous stingers. After being encircled by their tentacles, their stingers paralyze their target and push the prey into the mouth.


The Cyanea capillata is a cold-water jellyfish that inhabits the waters of the northern Atlantic, Pacific, and Arctic oceans. 

The Lion’s mane jellyfish is most commonly found off the coasts of North America, northern Europe, Russia, and Japan, although they can be rarely found drifting in the southern hemisphere. They sometimes move into the Baltic Sea’s southwest regions. Furthermore, they are frequently spotted in the English Channel, the Northern Sea, and various regions of Scandinavia.

This jellyfish is most at home in water ranging between 32°F (0°C) and 60°F (16°C) and can live in a range of salinity, drifting in both brackish and salt water. Because of their poor performance in warmer climates, they thrive in temperatures that are colder than 68°F. In warm oceans, they tend to glide close to the water’s surface and spend their final years settling in harbors.

Lion's mane jellyfish prefer deeper water but rarely live below 66ft
Lion’s mane jellyfish prefer deeper water but rarely live below 66ft

Lion’s mane jellyfish are typically deep-water jellyfish and can be found at a variety of depths, although they are typically found between the surface and 66ft (20m). These jellyfish generally prefer the deeper end of this range but can be found in abundance on the surface when their population spikes.

The Lion’s mane jellyfish, as mentioned, tends to drift further out at sea, although storms and rough currents can bring them to the surface and closer to the coastline.

Lion's mane jellyfish thrive in temperatures that are colder than 68°F
Lion’s mane jellyfish thrive in temperatures that are colder than 68°F


The Lion’s mane jellyfish has a complicated life cycle that goes through many stages before reaching adulthood.

The Lion’s mane Jellyfish can breed either asexually or sexually, similar to other species of jellyfish. By using external pollination, Lion’s mane jellyfish reproduces between early March and mid-May. In 30-40 days, larvae will remain just on the seafloor and evolve into polyps, which then turn into jellyfish. 

The adult female is prepared for procreation when she reaches the medusa stage. The female carries the fertilized eggs in her tentacles till they develop into larvae. When the larvae grow sufficiently, the mother abandons them to develop into polyps on a firm surface.

Fertilized eggs then develop into free-swimming larvae known as planula. These planulae eventually settle on the ocean floor, where they attach themselves to hard surfaces such as rocks or coral reefs.

Lions Mane jellyfish reproduce via external sexual reproduction
Lion’s mane jellyfish reproduce via external sexual reproduction

The planula develops into stationary polyps that produce asexually through budding. These new “buds” are identical offspring to the original polyp.

Tiny jellyfish are eventually produced from each bud. These are similar to the adult stage of the jelly, yet smaller and immature. These immature jellies are known as ephyrae.

Over time, and with enough nutrients, the ephyrae will eventually grow into a mature adult Lion’s mane jellyfish where it can reproduce and continue the cycle.


Ocean sunfish, seagulls, and leatherbacks are typical predators of Lion’s mane jellyfish. Younger, weaker Lion’s mane jellyfish are far more susceptible to being eaten by bigger predators. When these jellies mature, it’s indeed far harder for certain animals to consume them. They are protected from threats by their bulk and deadly stingers, which also turn their attackers into victims. 

The Lion's mane jellyfish grows rapidly, thanks to an abundance of food
The Lion’s mane jellyfish grows rapidly, thanks to an abundance of food

In some instances, adverse human activity will aid in the population numbers by disrupting the activity of Lion’s mane jellyfish natural predators, leaving plenty of food and little to no competition.

Facts About Lion’s Mane Jellyfish

  1. The longest documented Lion’s mane jellyfish measured 120 ft in length.
  2. With a length range of 1.5 to 6.5 feet, Lion’s mane jellyfish is the world’s largest jelly species.
  3. Even when dead, Lion’s mane jellyfish tentacles still can sting.
  4. Lion’s mane jellyfish have around 1,200 tentacles in total.
  5. Lion’s mane jellyfish only opening serves to bring in food and dispose of waste.
  6. In some regions, Lion’s mane jellyfish is seen as a delicacy and are used in traditional medicine.
  7. The Lion’s mane jellyfish is associated with the Greek god of the sea – Poseidon and can be considered good luck.
  8. The Lion’s mane jellyfish are capable of swimming and will migrate to more favorable water conditions.
  9. The tentacles of the biggest jellyfish produce a bioluminescent glow that can be seen in the dark.
  10. The Lion’s mane jellyfish grow quickly and have a lifespan of only 12 months.


Is Lion’s mane jellyfish dangerous?

Lion’s mane jelly produces a painful sting but is not necessarily life-threatening to humans. That said, although mild pain is common, allergic reactions or excessive exposure to their stinging tentacles could result in hospitalization or death.

What does the Lion’s mane jellyfish sting feel like?

The tendrils have stingers, and people find the sting to be unpleasant. Although the Lion’s mane jellyfish’s sting is not toxic, for certain people, it can result in life-threatening adverse reactions. Anecdotal evidence suggests that the sting initially feels like swimming into a pool of lukewarm fizzy water rather than being very unpleasant.

What happens if you touch Lion’s mane jellyfish?

If inflammation or sores are significant, seek medical attention, as Lion’s mane jellyfish delivers a highly painful sting. While waiting, extract the tentacle using tweezers if you’re available, scrape the region with a sterile stick, and afterward wash the skin with lukewarm water to decrease swelling.

Is it OK to touch the top of Lion’s mane jellyfish?

The standard operating procedure is to simply not touch or pick up the jellyfish, considering that their tentacles are always potent even when the specimen is clearly dead. However, the only part of the jellyfish that is actually acceptable to handle reasonably safely is the top side; attempts to lift it up can result in the tentacles swinging uncontrollably and being stung.

Can Lion’s mane Jellyfish sting through a wetsuit?

While the covered areas of the wetsuit are safe from stinging, exposed parts such as your hands, head, and feet are still susceptible to getting potentially stung by Lion’s mane Jellyfish. They lack the ability to pursue prey and simply float, so keeping a fair distance from them is the safest policy.

Why do Lion’s mane jellyfish get so big?

A long lifespan and a lack of natural predators contribute to the large size that these jellyfish grow to, but it is the abundance of available food that has the biggest influence. Because these jellies are opportunistic eaters, they rely on prey to pass into their tentacles. This happens at a significantly higher rate when food is more abundant.

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