Lion's Mane Jellyfish | Oceana
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Corals and Other Invertebrates

Lion's Mane Jellyfish

Cyanea capillata


Cooler regions of Pacific, Atlantic and North Sea region


Pelagic (Open Ocean)

Feeding Habits

Foraging Predator

Conservation Status



Class Scyphozoa (true jellies), Family Cyaneidae


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The lion’s mane jellyfish is not only the largest jelly species in the world, but it also harbors a powerful sting that it uses to catch its prey. Most humans have little to fear from this ferocious jelly, but its poison is more than enough to scare away enemies, thus creating a safe space for both the jelly and other species that are lucky enough to be immune to the toxin.

The lion’s mane jellyfish cannot be missed in the open ocean where it prefers to float about. With tentacles up to 190 feet long and a bell diameter of almost 7 feet wide, some individuals even rival in size the blue whale, the largest animal in the world. Most lion’s mane jellyfish live in the Arctic and North Pacific Ocean from Alaska to Washington where the waters are cool. Its ‘mane’ of long, hair-like tentacles hanging from the underside of its bell-shaped body is the inspiration behind the lion mane’s common name. The mouth is situated on the bell’s underside, surrounded by tentacles that are divided into eight clusters of up to 150 tentacles each. These tentacles are equipped with nematocysts containing poison that stun prey when they are enveloped. The top of the bell is usually dark yellow or red in color and thick in the center, but thins out towards the edges. The lion’s mane jellyfish also possess bioluminescent abilities, meaning it’s able to produce its own light and glow in the dark underwater.

Using the powerful sting of its tentacles, the lion’s mane jellyfish catches small fishes, tiny crustaceans and even other jellyfish to satisfy its diet. Lion’s mane jellyfish are continual swimmers that can cover great distances when strong marine currents are present, and while most individuals prefer to swim solo, large swarms occasionally occur when storms and tides are prevalent. The lion’s mane jellyfish breeds in March and early May via external fertilization. Larvae will settle on the seabed and develop into polyps that eventually grow into jellyfish within 30-40 days.

Scientific research has suggested that jellyfish actually thrive in areas that are affected by human activity. Overfishing, climate change and pollution have helped promote more frequent jellyfish swarms while reducing the jellies’ main predators and competitors and increasing their prey. These factors have created a favorable environment for this species, and few threats are known to the lion’s main jellyfish or other jellies.

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