It was just another descent into the inky deep when it appeared: a ghostly shape hovering in midwater, delicate and otherworldly.
For a few fleeting minutes, the remotely operated vehicle SuBastian held steady in the Southern Ocean near Antarctica, recording the first-ever footage of a colossal squid alive in its natural habitat. Colossal squid can grow up to 10m (33ft) in length and are the heaviest invertebrates in the world – but, until now, have never been seen alive.
The discovery took place during a 35-day expedition to the South Sandwich Islands, a remote volcanic arc in the Southern Ocean, co-led by the Nippon Foundation–Nekton Ocean Census project aboard Schmidt Ocean Institute’s state-of-the-art research vessel Falkor (too).
The aim was to accelerate species discovery in the deep sea – but no one expected to meet one of the ocean’s most elusive giants along the way.
“We were using SuBastian to do some trench work that day, going down to depths of about 2,000 metres,” Dr Michelle Taylor, chief scientist of the expedition and a senior lecturer at the University of Essex, tells BBC Science Focus.
“As SuBastian goes through the blue water, we sit in the control room, which is filled floor to ceiling with screens showing all of the high definition cameras and sensor data on SuBastian. Lots of scientists are in the room, and you sit and see what comes up in the water column.”
On 9 March, at around 600m (almost 2,000ft) deep, the pilots spotted something and began to hover.
“None of us on board were squid experts... but we recognised straight away it was some gorgeous kind of glass squid,” Taylor says. “We recorded it for around three minutes and then moved back down to carry on with our mission to explore the deep sea floor.”
Colossal squid are among the most mysterious creatures on Earth. Until now, they had only ever been seen as dead specimens – either hauled up accidentally by fishing vessels or pulled from the stomachs of whales. Seeing one alive, let alone recording it, was the marine biology equivalent of finding a unicorn.
And yet the squid in question wasn’t even fully grown. “It was a teenager,” Taylor explains. “It doesn't have some of the physical features like the stalked eyes that real tiny babies have. But it definitely wasn’t fully formed. Who would have thought that the first sighting of the colossal squid would have been such a modest size?”
The footage, beamed live to YouTube during the dive, was initially flagged by viewers in the chat who suspected it might be a colossal squid.
Taylor followed up with Dr Kat Bolstad, a cephalopod expert from Auckland University of Technology, and other colleagues who confirmed the ID with the help of the 4K video footage from the dive.
The tell-tale clue: distinctive hooks along the squid’s arms, not found on the otherwise similar glass squid.
“[Knowing it‘s a colossal squid] just takes something that was beautiful anyway and makes it something extraordinary,” Taylor says.
Though the colossal squid stole the headlines, it wasn’t the only highlight from Falkor (too)’s recent expeditions. A little over a month earlier, researchers also captured the first in situ footage of a glacial glass squid, another deep-sea species rarely seen alive.
Both sightings were the product of long, meticulous dives using SuBastian, capable of descending to 4,500 metres (3 miles), and of the growing role of ‘telepresence’ science – which streams real-time deep-sea footage to a global audience of researchers and enthusiasts alike.
“That’s a new step – bringing the world into the deep sea in a way that just hasn’t been possible before,” Taylor says. “You have people in the scientific community, and also just enthusiasts, communicating with you. Often they know more about the things we’re seeing than we do.”
Beyond the thrill of discovery, Taylor emphasises the deeper purpose of the mission: to better understand and protect life in the deep ocean – Earth’s largest and least-explored habitat.
“This is the final frontier,” she says. “I find it baffling why people try to get to other planets when we’ve barely scratched the surface of this one.”
Ocean Census aims to accelerate the discovery of new species, which remains painstakingly slow – often taking over a decade from specimen collection to official recognition.
In its first few years, the project has already documented more than 800 new species, thanks to its focus on under-explored regions and real-time collaboration with a global network of taxonomists.
The sighting of a juvenile colossal squid may have been serendipitous, but for Taylor, it’s only the beginning.
“There’s still so much left out there to discover,” she says.
About our expert
Michelle Taylor is a senior lecturer in the School of Life Sciences at the University of Essex. Her research focuses on the deep-sea and its many and varied habitats. As a principal investigator for the Ocean Census, she led The Nippon Foundation-Nekton Ocean Census team on the South Sandwich Islands expedition.
Read more: