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Just after 10:00 a.m. on January 6, 2023, Matthew Mulrennan’s underwater camera captured a unique sighting in the Southern Ocean about 1,100 kilometers south of Argentina: there, 176 meters below his vessel, was a lone octopus. runs through the freezing water. With its outstretched vermilion tentacles, transparent body, and faint blue bioluminescent glow, this 12-centimeter-long octopus is potentially the first colossal octopus ever to be filmed in its natural habitat.
Video captured nearly 200 meters below the surface of Antarctica shows what could be a juvenile colossal octopus living freely in its natural habitat. It is possible that it is not a colossal squid, but another species of the closely related glass squid. Video courtesy of Matthew Mulrennan/Kolossal
Mulrennan, a marine scientist and founder of the California-based nonprofit Kolossal, has been working since 2017 to capture footage of the wild colossal octopus. Cephalopod experts are convinced that Mulrennan filmed some kind of glass squid, the scientific family to which the colossal octopus belongs. But they remain uncertain whether it was a young colossus, an adult Galiteuthis glacialis, or a previously unknown species in a closely related genus Taonius.
The water in Antarctica where Mulrennan’s team spotted the octopus was filled with marine snow, giving the video a grainy quality reminiscent of the first photographs of another little-known cephalopod: the giant squid.
Although both cephalopods are so elusive they’re practically legendary—and are often compared to the mythical kraken—colossal octopuses have larger, heavier bodies and slightly shorter tentacles than their giant brethren. While giant octopuses were first photographed and filmed in their natural habitat in 2004 and 2012, the only sightings of colossal octopuses have come from carcasses or animals brought to the surface.
Until maybe now.
Colossal octopuses were first scientifically described by zoologist Guy Robson in 1925 after a sperm whale washed up on the Falkland Islands with two colossal squid tentacles in its stomach. Since then, the massive animals have rarely been caught, photographed or even seen. That’s an amazing feat for a creature longer than a shipping container with eyes the size of volleyballs. As adults, colossal octopuses are the largest invertebrates on Earth. They eat Patagonian toothfish (also known as Chilean sea bass) and are hunted by sperm whales. When they are young, the colossal squid seem to venture closer to the surface of the ocean, where they are collected by penguins, albatrosses, seals and Patagonian toothfish. Little is known about their behavior; most clues come from nibbling on line, examining predator stomachs and the occasional squid carcass that washes up on the beach.
William Reid, a marine biologist at Newcastle University in England, was lucky enough to get up close and personal with the colossal octopus after fishermen unexpectedly hauled it up in 2005 near South Georgia Island, which is located between Antarctica and South America. Although its several-meter-long shell was too heavy to save, Reid’s incomplete 200-kilogram specimen revealed how the hooks and suction cups that line the squid’s arms can pop out, giving the animal an impressive grip but also offering easy separation from prey and predators. .
In the depths of the ocean, where little light penetrates, Reid suspects that the colossal octopuses are ambush hunters, patiently waiting for prey to wander into range, then using their long arms to stuff the catch into their beaks. He says the giant squid’s eyes may be adept at seeing bioluminescence, which could alert them to hungry sperm whales approaching.
Colossal octopuses have also been documented several times. Soviet fishermen caught and photographed the first whole colossal octopus in 1981 off East Antarctica. In 2003, New Zealand fishermen caught a dead 300-kilogram juvenile colossal squid in the Ross Sea, Antarctica, and then in 2007 pulled up a live 500-kilogram adult from a depth of 1,500 meters. And in 2008, Russian scientists caught one further west in the Dumont d’Urville Sea.
But no one has ever seen a colossal octopus living undisturbed hundreds of meters below the surface where it naturally resides. And as Reid points out, because colossal octopuses tend to collapse under their own weight when pulled from the deep sea under high pressure, studying them in their natural environment is the only way to see their behavior and anatomy fully intact.
Therefore, from December 2022 to April 2023, Mulrennan and his crew set off on four multi-week trips from Ushuaia, Argentina, aboard the ship. Ocean Endeavour, a tourist-packed expedition vessel operated by Intrepid Travel. Mulrennan and the Kolossal team sailed alongside around 200 curious tourists, traveling to South Shetland, South Georgia, the Antarctic Peninsula and other sub-Arctic regions in search of the oversized octopus.
While passengers slept and disembarked on day trips to see penguins, whales and the icy terrain of Antarctica, scientists — including Jennifer Herbig, a doctoral student at Memorial University in Newfoundland and Labrador — took turns launching a tethered underwater camera from one of the ship’s bridges. into the freezing water below.
“We’d put the camera in the water at midnight or 1:00 in the morning, be up until 4:00 or 5:00 and then have to get up at 6:00 or 7:00,” says Herbig. With the camera dangling up to 400 meters underwater, it was an almost constant effort to prevent it from getting caught on the sea ice and disappearing into the depths.
In total, the team captured 62 hours of high definition footage. Along with their potential colossal octopus, the researchers spotted a giant volcanic sponge – animals thought to live up to 15,000 years – and dozens of other deep-sea Antarctic species.
It was a tough job, made easier by the ship’s other passengers, who brought cookies and hot chocolate to the scientists during long night deployments. Herbigová again enjoyed the interest of tourists. “They could just look over our shoulders and see what we were doing, so we have to explain some of the science,” he says.
“Every day on the boat I was asked, ‘Did you find the octopus?'” Mulrennan says. “People really want to know more about these big kraken-like species” – especially the ship’s cook, who kept joking about cooking octopus if he could find it.
Whether or not the video captured by Mulrennan’s team turns out to be a juvenile colossal squid—that final decision depends on ongoing research by octopus experts at New Zealand’s Auckland University of Technology—Kolossal researchers aren’t done with their quest.
While last year’s expedition relied largely on using an underwater camera to film near the noisy craft, the team hopes to visit Antarctica again as soon as November 2024, armed with a much broader set of tools.
Mulrennan is looking to upgrade from one underwater camera to up to a dozen that he could deploy simultaneously, and he wants to add remote-controlled cameras that would allow filming further away from the ship. Another way to improve their technique, Herbig says, would be to get longer camera cables to peer even deeper into the colossal squid’s chilly domain. Herbig adds that they could also bring equipment to analyze environmental DNA and measure biomass, which will help the team study the multitude of creatures that share this deep-sea habitat.
With a tattoo on his left arm commemorating zoologist Guy Robson’s sighting of a colossal octopus in 1925, Mulrennan hopes to lead or inspire a verified underwater filming of a live, wild colossal octopus by 2025.
“If finding a giant octopus was like landing on the moon, then finding a colossal octopus will be like landing on Mars,” he says.