Although it is exactly 100 years since the species was given a name, only now has video footage of a live colossal squid been captured in its natural environment – the deep ocean.
The breakthrough has come thanks to an international scientific team onboard the Schmidt Ocean Institute’s research vessel Falkor (too), exploring the remote South Sandwich Islands in the South Atlantic.
Adults of the species, which have only ever been seen dead or dying in nets in the past, live up to their common name and are estimated to grow as long as 7m. Weighing 500kg, these are reckoned to be the planet’s heaviest invertebrates.
All being well, the specimen of Mesonychoteuthis hamiltoni caught on camera will reach that size but for now it is a 30cm juvenile. It was swimming at a depth of 600m when spotted by the institute’s ROV SuBastian.
The just-revealed sighting occurred on 9 March, while Falkor (too) was on a 35-day Ocean Census flagship expedition to find new marine life, run by Nippon Foundation and Nekton.
Glass squid family
Colossal squid belong to the glass squid (Cranchiidae) family, and a significant observation had already been made on the previous Ocean Census expedition on 25 January. This was the first confirmed footage of another live Cranchiidae species, the glacial glass squid (Galiteuthis glacialis), filmed from Falkor (too) 687m deep in the Bellingshausen Sea near Antarctica.
The latest expedition was a collaboration between Schmidt Ocean Institute, the Nippon Foundation-Nekton Ocean Census and GoSouth, a joint project between the UK’s University of Plymouth, the GEOMAR Helmholtz Centre for Ocean Research in Germany and the British Antarctic Survey.
“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 Dr Kat Bolstad of Auckland University of Technology, one of the independent experts who helped 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.”
Little is known about the glass squid life-cycle, but juvenile colossal squid have a transparent appearance that they will later lose. The species can be distinguished from G glacialis by hooks on the middle of their eight arms, but as juveniles both have sharp hooks at the end of their two longer tentacles.
Back-to-back success
“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 Schmidt Ocean Institute executive director Dr 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.”
SuBastian has previously captured the first confirmed footage of at least four squid species in the wild, including the Spirula spirula (ram’s horn squid) in 2020 and Promachoteuthis in 2024, both reported on Divernet, and there is one more first sighting that is awaiting confirmation.
“These unforgettable moments continue to remind us that the ocean is brimming with mysteries yet to be solved,” said Virmani.
Also on Divernet: Flying spaghetti monsters among deep seamount rarities, ‘Minion’ squid filmed for first time, Another bizarre squid recorded
