A juvenile colossal squid (Mesonychoteuthis hamiltoni) has been filmed alive in its environment by a team of marine biologists on board Schmidt Ocean Institute’s R/V Falkor (too) in waters off the South Sandwich Islands.
The colossal squid (Mesonychoteuthis hamiltoni) in its natural habitat. Image credit: Schmidt Ocean Institute.
Also known as the Antarctic cranch squid or giant squid, the colossal squid is a member of the glass squid family Cranchiidae.
The species grows up to 10-14 m in length and can weigh up to 500-700 kg, making them the heaviest invertebrate on the planet.
Little is known about their life cycle, but eventually, they lose the see-through appearance of the juveniles.
“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, a researcher at the Auckland University of Technology.
“For 100 years, we have mainly encountered them as prey remains in whale and seabird stomachs and as predators of harvested toothfish.”
A 30-cm-long juvenile colossal squid was captured on video at a depth of 600 m by the remotely operated vehicle (ROV) SuBastian on March 9, 2025.
“It’s incredible that we can leverage the power of the taxonomic community through R/V Falkor (too) telepresence while we are out at sea,” said Dr. Michelle Taylor, a researcher at the University of Essex and the expedition’s chief scientist.
Additionally, on January 25, 2025, a team on the previous Falkor (too) expedition filmed the first confirmed footage of the glacial glass squid (Galiteuthis glacialis) in the Southern Ocean near Antarctica.
Galiteuthis glacialis is another glass squid species that has never been seen alive in its natural environment before.
“One of the most distinguishing characteristics of colossal squid is the presence of hooks on the middle of their eight arms, which help differentiate them from Galiteuthis glacialis,” said Dr. Aaron Evans, an independent expert on the glass squid family.
“Otherwise juvenile colossal squid and Galiteuthis glacialis are similar, with transparent bodies and sharp hooks at the end of their two longer tentacles.”
“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 Dr. Jyotika Virmani, Schmidt Ocean Institute’s executive director.
“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.”
