Lion's Mane jellyfish It is not only the largest jelly species in the world, but it also harbors a powerful sting that it uses to catch its prey.With tentacles up to 120 feet long, 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.