As It Happens

This 'really strange' spiralling sea creature may be the longest animal in the ocean

A team of scientists in Western Australia have spotted what they believe may be the longest creature ever discovered in the ocean, or even on the planet.

Siphonophore discovered off the coast of Australia measures 47 metres around its outer ring

This massive, spiraling siphonophore was discovered off the coast of Australia. (Schmidt Ocean Institute)


A team of scientists in Western Australia have spotted what they believe may be the longest creature ever discovered in the ocean, or even on the planet.

The "enormous spiral floating in the water column" is called a siphonophore, and its outer ring is estimated to be 47 metres long, says Nerida Wilson, the lead researcher in the expedition. 

But its full length is still a mystery. It could measure up to 119 metres when all is said and done, a spokesperson for the Schmidt Ocean Institute told Newsweek.

"There's a lot of conjecture about how long it really is," Wilson, the manager of the Molecular Systematics Unit at Western Australian Museum, told As It Happens guest host Piya Chattopadhyay. 

"We're in the process of trying to measure it more accurately and we'll update the world when we get the final word on it."

What may be the world's longest animal discovered in Australia

4 years ago
Duration 1:06
A team scientists have discovered a siphonophore that might be the world longest animal floating off the coast of Western Australia. (Schmidt Ocean Institute)

Currently, the longest marine animal is believed to be the lion's mane jellyfish at about 36.5 metres, according to the New York Times. The world's longest animal, according to Guinness, is the ribbon worm at 55 metres.

Siphonophores are predators that reside in the deep ocean and are made up of many small clones working together as one animal, Wilson said.

They are typically elongated or rope-like and generally reach lengths of around 40 metres, according to Cell Magazine

The animal is closely related to corals and anemones, but would be most likened in appearance to jellyfish. 

"They're really strange animals," Wilson said. "A little group of clones somehow communicate with each other and decide, well, we're going to take over the role of feeding and another group of clones will take over the role of reproduction."

Nerida Wilson, Greg Rouse and their colleagues watch the creature in astonishment. (Schmidt Ocean Institute)

Wilson said that like most interesting discoveries, this one was a "complete accident." 

The team was surveying the deep sea floor for animals, when after commuting toward the surface for a couple of hours, they found the creature. 

"We tend to have at least one or two scientists watching the camera because you never know what you might stumble across. And on this particular day, it was this amazing siphonophore," she said.

Spiral formation is 'something pretty special'

Its size wasn't the only thing that stood out.

"The spiral nature of it just sitting in the water column was very unusual," Wilson said.  "Normally, they kind of hang like a piece of string. We all knew we were seeing something pretty special."

It's unclear how siphonophores are able to reach such enormous scales. Wilson says its size constraints could come down to the animal's ability to "hold itself together" at larger sizes. 

The siphonophore wasn't the only strange and rare creature the team discovered on the expedition into Western Australia's underwater canyons.

Wilson says they also came across some "amazing sea cucumbers" with long tails that look "like a squirrel" and "incredible giant hydroids."

"On a trip like this, we have a long period of planning and then we have a month-long expedition where we intensively gather samples," she said. "Then we spend the next few years identifying species." 

Written by Adam Jacobson. Interview produced by Tayo Bero. 

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