Which Is the Largest Jellyfish in the World?

The lion's mane jellyfish, Cyanea capillata, lives in the cold waters of the Arctic, North Atlantic and North Pacific. One specimen that washed ashore in Massachusetts Bay in 1870 had a bell 2.3 metres across and tentacles about 36.5 metres long. That makes it potentially longer than a blue whale, although most individuals are much smaller. Its hundreds of tentacles are arranged in eight clusters and carry stinging cells used to catch fish, plankton and other jellyfish. Its sting is painful to humans but rarely dangerous.