Lion’s Mane Jellyfish

Lion’s mane jellyfish, commonly called the hair jelly or giant jellyfish, is a species of marine jellyfish that inhabit the cold, subarctic waters of the oceans in the Northern Hemisphere. Some populations of the same species are sometimes observed in the Gulf of Mexico and in oceans off the coast of Australia and New Zealand. The lion’s mane jelly is named so because of its long, trailing tentacles that resemble the thick mane of a lion. With tentacles measuring up to 120 feet, it is the largest species of jellyfish in the world.

Scientific Classification

Cyanea capillata

Table Of Content

Scientific Classification

Cyanea capillata

Physical Description and Appearance

Size: These jellyfish vary in size, with the larger individuals (that live in the Arctic Ocean) having a bell diameter of 2-2.4 m (6 ft 7 in-8 ft) and the smaller ones (found in the lower latitudes) having a bell diameter of about 30-80 cm (12-31.5 in). The larger specimens have tentacles measuring 30-36.5 m (100-120 ft), which is bigger than a blue whale.

Lion’s Mane Jellyfish

Weight: The largest of the lion’s mane jellyfish could weigh up to 480 lbs while average-sized specimens weigh about 200 lbs.

Color: Larger individuals range from bright crimson to dark purple and the smaller specimens are usually lighter orange to tan, but sometimes they can be colorless.

Body: Their bell consists of eight lobes or lappets, each of which consists of 70-150 tentacles set in four distinct rows. The rhopalium, a balance organ, exists at each of the indentations along the edge of the bell.

Mouth: Situated on the underside of the bell, the mouth has broad oral arms, which contain numerous stinging cells.


It is distributed across the Arctic, northern Pacific, and northern Atlantic Oceans. It is commonly found in the Irish Sea, English Channel, North Sea, and western Scandinavian waters. The lion’s mane jelly is sometimes found in the southwestern Baltic Sea.

What Kind of Habitats do Lion’s Mane Jellyfish live in

They live in the open ocean and are typically found drifting within 20 m (65 ft) of the surface.

Lion’s Mane Jellyfish Habitat
Lion’s Mane Jellyfish Pictures


The lion’s mane jellyfish, like other jellyfish species, have a short lifespan. They live for only one year during which they go through four developmental stages, which include larval, polyp, ephyrae, and medusa stages.


Being a voracious predator, the giant jellyfish captures and eats zooplankton, small shrimps, rotifers, copepods, ctenophores, and small jellyfish species like moon jellyfish.

Behavioral Characteristics

  • These jellyfish are constant swimmers and can travel great distances with the help of marine currents.
  • They also glide vertically in order to move around in the water.
  • They are usually most active during the summer and autumn because they develop into their adult size by this time of the year and are swept to the shore with the currents.
  • They form shoals, which mean they swim together in large groups. Swarms that are several kilometers long are observed in the North Sea and off the coast of Norway.
Lion’s Mane Jellyfish Sting
Lion’s Mane Jellyfish Image


  • The rhopalia, present along the margin of the jellyfish’s bell, are balance organs that help it position itself.
  • Its tentacles are extremely sticky and are equipped with stinging cells called nematocysts that contain venom used for stunning and capturing prey, as well as escaping from predators.
  • It has bioluminescent ability, which means it can produce light and glow in the dark.

Mating and Reproduction

The lion’s mane jellyfish, like other jellyfish species, can reproduce sexually in their medusa stage and asexually in their polyp stage. Female jellyfish carry the fertilized eggs in their tentacles, where these eggs mature into larvae. Once the larvae become old enough, the female jellyfish attach them to a firm surface where they develop into polyps. These polyps start reproducing asexually, forming small creatures known as ephyrae. Each of these ephyrae gets separated from the stacks, eventually turning into the medusa form and then become full-grown jellyfish.

Conservation Status

The lion’s mane jellyfish is not in danger of extinction and has not received any special status from the IUCN Red List.

Lion’s Mane Jellyfish Size
Picture of Lion’s Mane Jellyfish

Interesting Facts

  • While the sting from a lion’s mane jellyfish is not known to be fatal in healthy individuals, it can cause localized redness, temporary pain, and a burning sensation. Vinegar is used for deactivating the nematocysts, but medical attention is necessary after exposure.
  • Its remains, if broken into pieces, can also sting humans. Such an incident occurred in July 2010 when hundreds of beachgoers in Wallis Sands State Beach, New Hampshire were stung by the remains of a single specimen.
  • This jellyfish species has appeared in the ‘The Adventures of the Lion’s Mane’, a short story of Sherlock Holmes.
  • The lion’s mane jellyfish are fast swimmers and can cover long distances by using the marine currents.

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