The Longest Jellyfish in the World
Now that we have our jelly basics down, let’s talk about the lion’s mane jellyfish, or Cyanea capillata. Collins said that in the 1800s, a scientist observed a lion’s mane jellyfish with a disk that had a diameter of 7.5 feet (2.2 meters) and tentacles that exceeded 120 feet (36.5 meters). These jellies are more common in colder temperate to polar waters, but some species can also be found in subtropical and tropical waters. In the U.S., they can be found in the Atlantic and the Gulf of Mexico.
While the lion’s mane is famous for being the largest jellyfish species, there is another species that rivals it: Nomura’s jellyfish (or Nemopilema nomurai if you’re into scientific names). Its bell has been reported to be up to 6.5 (2 meters) across and large specimens can weigh 440 pounds (200 kilograms).
“So, both species can be really large, with Cyanea being the longest and Nemopilema having the largest mass,” Collins said.
