Lion’s Mane Jellyfish

An encounter with the world’s largest jellyfish, the Lion’s Mane Jellyfish, can certainly make for an intimidating one!

Not only is the Lions Mane jelly the largest of all jellyfish species – but the longest one ever recorded dwarfs the largest known animal on the planet in the blue whale!

Keep on reading for even more fascinating lions mane facts!

Lion’s Mane Jellyfish

Scientific Name:

Also Known As

Where Do Lion’s Mane Jellyfish live

With a preference toward colder waters you’ll find that the Lion’s mane jellyfish are mainly found in the northern Atlantic and the northern Pacific Ocean.

They’re also a common sighting in UK waters, and in the Baltic sea and spend their life cycle closer to the oceans surface at a fairly shallow 20meters/60 feet.

Though they spend their lives at the perfect depth for scuba divers to spot them, an encounter with a lion mane jellyfish is not as common as you might think as they mainly inhabit the open ocean as opposed to coastal waters.

lions mane jellyfish

Lion’s Mane Jellyfish Physical Characteristics

The physical appearance of a Lion’s mane jellyfish can vary depending on it’s age and geographic location.


lions mane jellyfish color
lions mane jellyfish size

A very young Lion’s mane jelly will often be white or light brown in color, which will then deepen to a more brown/orange/dark yellow as it ages. The most mature Lions mane jellies tend to darken into a dark red.


are lions mane jellyfish dangerous

The bell of this jellyfish is rather flat shaped and can grow very wide. The larger specimens that are found in the northern Atlantic can reach up to 6-8 feet in width, whilst their smaller Southern counterparts typically only reach 1-2 feet.

The bell of the jelly is divided into eight lobes, and from each of these lobes are between 70-150 tentacles – That’s a combined total of up to 1200 tentacles!

The frilly oral arms under the bell form a large mass and are often described as resembling that of a Lion’s mane (hence where this jellyfish gets its name).

The stinging cells found on it’s oral arms and the long stinging tentacles (described as being very sticky) that trail from the Lion’s mane jellyfish pack a powerful sting for their prey. Then once immobilized by the poisonous toxins, their prey will be transported up towards the jellyfish’s mouth.

The Lion’s mane jellyfish’s tentacles can often reach up to 100 feet in length (30 meters), so it’s best to give this jelly a wide berth if you come across one! Especially as their long thin tentacles can be difficult to spot.

The largest Lion’s mane jellyfish recorded had a bell diameter of 7 feet, and tentacles that were 120 feet in length!

Are Lion’s Mane Jellyfish Dangerous?

To humans, the lion’s mane jellyfish sting is not especially dangerous. It does still pack a powerful sting that can be quite painful, but it is not one that is generally considered deadly (unlike the deadly box jelly!).

The painful sting of a Lion’s mane jellyfish will cause pain and irritation to the skin. The sting could be more severe (and dangerous) for unlucky individuals who exhibit an allergic reaction to the sting.

Lion’s Mane Jellyfish Prey & Predators

A Lion’s mane jellyfish main prey consists of; zooplankton, small crustaceans & fish, and other smaller jellyfish like moon jellies.

It’s predators consist of; Anemones, Ocean sunfish and sea turtles (usually leatherback turtles)

The below video shows footage of the lion’s mane jelly feasting on other moon jellies, and one being consumed by a wall of anemone’s!

Lion’s Mane Jellyfish Fun Facts

  1. It eats and poops through the same orifice (yum)
  2. You may sometimes see juvenile fish swimming with the lion’s mane jellyfish. These fish seek out the Lion’s mane jelly for protection from other predators. Stalked barnacles may also reside within the bell of the jellyfish itself – gaining protection from the lion’s mane as well as sharing the food resources that the jelly consumes.
  3. Lion’s Mane Jellies are bioluminescent and can glow in the dark!
  4. The Lion’s mane jelly has up to 1200 tentacles!
  5. Though Lion’s mane jellies are mainly solitary, they will sometimes form large ‘blooms’. Due to the size of the jellyfish, these blooms (which may contain thousands!) can reach up to 1km wide!
  6. The tentacles can still sting you after the jellyfish has died, and even if they are no longer attached to the jelly itself!

I hope you enjoyed this article on the fascinating Lion’s Mane Jellyfish. If so then you may also be interested in reading:

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Gia Halliday

Hey, my names Gia! My biggest passions are food, travel and basically anything to do with being in the water. Combine all of that with an addiction for buying gear and you end up with with this website!