Lion's Mane Jellyfish

The lion’s mane jellyfish (Cyanea capillata) are found primarily in colder waters in the open ocean and they are the largest species of jellyfish that we know of.

Physical description

These ginormous jellies have bells (top portion) that can reach up to feet wide, along with tentacles that can grow well over 100 feet. Their bells are divided into 8 radially symmetrical portions that can hold between 70 and 150 each. This means most lion’s mane jellyfish have anywhere from 560 and 1,200 tentacles. Each tentacle has small barbs containing neurotoxins that sting prey. All of the tentacles together resemble a lion’s name, which is where their name comes from. Lion’s mane jellyfish can range from bright red to dark purple to orange or even pink in color. They are not very active swimmers and they tend to let the ocean currents move them throughout the water.

Geographic Range & Habitat

Lion’s mane jellyfish live in cold waters in the North Atlantic, North Pacific, and Arctic Oceans. They are often found near British Columbia and between Alaska and Washington in the United States. Generally, they do not migrate close to shore and they prefer to remain within the bathypelagic zone, about 1 mile deep, and are not a threat to swimmers and divers.

Image by Alexander Semenov
Image by Alexander Semenov


Despite their gigantic size, lion’s mane jellyfish tend to feed on much smaller prey. The majority of their diet consists of zooplankton (tiny animals drifting through the water). Zooplankton are either creatures who spend their whole lives as plankton, or they are small, immature stages of larger animals. Small fish, shrimp, and other jellyfish also are a staple in their diet. Prey animals are grabbed, wrapped in the tentacles, and stunned by the neurotoxins.


All jellyfish, lion’s mane included, can reproduce both sexually and sexually. In their polyp phase, lion’s mane jellies reproduce asexually by a process called strobilation. Essentially, the jellyfish polyps separate and become two or more entities that will become jellies. Sperm and egg cells are stored in the stomach wall and are released through the mouth. The sperm and egg mingle and form larvae in the water. The larvae then settle on the substrate to become polyps. The polyps will then begin their asexual reproduction.


Lion’s mane jellyfish have few predators which include, birds, large fish, sea turtles, and other jellyfish. They are have not been evaluated by the IUCN (International Union for Conservation of Nature) and they are believed to not be threatened with extinction.


Image Sources (Image by Alexander Semenov)

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