An international research team has caught images in the Atlantic Ocean depths of a baby colossal squid — and is now setting its sights on tracking down the elusive adult.

Marine biologists believe colossal squids can grow up to seven meters (23 feet) in length and weigh as much as 500 kilograms (1100 pounds), which makes them the heaviest invertebrate on the planet. 

How much do we know about the colossal squid?

The footage taken off the South Atlantic's South Sandwich Islands last month was taken as part of an expedition to encounter new sea life, California's Schmidt Ocean Institute said.

Viewed some 600 meters (nearly 2,000 feet) below the surface, the young squid is only about 30 centimeters (a foot) long with a transparent appearance and thin arms.

Not much is known about the colossal squid's life cycle, but eventually, they lose the see-through appearance of the juveniles.

Fishermen have previously filmed dying adults, but they have never been seen alive at depth.

"It's exciting to see the first in situ footage of a juvenile colossal and humbling to think that they have no idea that humans exist," said Kat Bolstad of the Auckland University of Technology, one of the independent scientific experts the team consulted to verify the footage.

"For 100 years, we have mainly encountered them as prey remains in whale and seabird stomachs and as predators of harvested toothfish."

"I really love that we have seen a young colossal squid first. This animal is so beautiful," said Bolstad, adding that researchers were now testing different cameras seeking to grab footage of an adult.

The 35-day expedition that captured the footage of the colossal squid was an Ocean Census flagship expedition searching for new marine life — a collaboration between Schmidt Ocean Institute and Japanese, UK and German research institutions.

Glacial glass squid also recorded

A previous expedition in January recorded the first-ever images of the glacial glass squid — another glass squid species that has never been seen alive in its natural environment before —  in the Southern Ocean near Antarctica.

The animal can be seen with its arms roughly above its head, similar to the "cockatoo pose" of other glass squids.

"The first sighting of two different squids on back-to-back expeditions is remarkable and shows how little we have seen of the magnificent inhabitants of the Southern Ocean," said the Schmidt Ocean Institute's executive director, Jyotika Virmani.

"Fortunately, we caught enough high-resolution imagery of these creatures to allow the global experts, who were not on the vessel, to identify both species."

So far, the institute's remotely operated vehicle has captured the first confirmed footage of at least four squid species in the wild.

They include the Ram's Horn Squid in 2020 and the Promachoteuthis in 2024, with one more first sighting yet to be confirmed.

"These unforgettable moments continue to remind us that the Ocean is brimming with mysteries yet to be solved," Virmani said.

Edited by: Zac Crellin