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Large golden lion's mane jelly with dense flowing oral arms and trailing tentacles against blue

Lion's mane jelly

Cyanea capillata

Not on exhibit
Animal type
Invertebrates
Ecosystem
Open ocean
Relatives
Egg yolk jelly; Family: Cyaneidae
Diet
Tiny crustaceans, zooplankton, small fishes, moon jellies
Range
Arctic and North Pacific Ocean from Alaska to Washington; rarely seen as far south as California
Size
Between 19 inches (50 cm) and 3 feet (1 m) in bell diameter

Meet the lion's mane jelly

This colorful jelly has a very toxic sting, but reports of human fatalities are few. They're considered a giant jelly; their bells that can reach about three feet (1 m) in diameter and their tentacles can grow to more than 100 feet (30.5 m) long. That's longer than a 90-foot (27.4 m) blue whale, the largest mammal on Earth, but smaller than the 130 feet (39.6 m) of a giant siphonophore (a gelatinous relative). The largest specimens are found in Arctic waters.

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Conservation

Leatherbacks are unique among sea turtles in that their primary food is jellies like the lion's mane. These turtles accidentally consume drifting plastic debris, confusing it for their gelatinous prey. You can help the sea turtles, jellies, and countless other species by cutting down on single-use plastic like disposable takeout containers.

Cool facts

  • A Cyanea sea jelly was the murder weapon in a Sherlock Holmes mystery called "The Adventure of the Lion's Mane."
  • Although the lion's mane's sting can be potentially fatal, most swimmers who encounter this gentle beast survive to tell the story.
  • Some fishes, such as the southern harvestfish and gulf butterfish, are resistant to the toxin of the lion's mane. They're often found nibbling on this jelly's bountiful bell.

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