Colossal Octopus (Mesonychoteuthis hamiltoni) is one of the great mysteries of the ocean. There are no photos or footage of the colossal octopus living in its natural habitat. What we know about this ocean animal comes from the few specimens that have been found in fishing nets or washed up on beaches.
An international research team has come up with an ambitious plan to find and study the colossal octopus in its natural home by 2025, the 100th anniversary of the species’ discovery. Between December 2022 and March 2023, the team traveled to Antarctica four times to try to find the colossal octopus. They used a polar tourist vessel called Ocean Endeavour equipped with a depth camera system that can be launched to a maximum depth of 400 meters (1,312 feet).
The colossal octopus is believed to be 14 meters (46 feet) long and weigh at least 500 kilograms (1,100 pounds). It is a multiple world record holder and has earned the title of the world’s largest invertebrate (at least in terms of weight). This elusive species is believed to live in the deep sea in the Southern Ocean surrounding Antarctica.
Although the team was unable to find an adult, they did capture footage of a glass octopus that measures 10–12 centimeters (3.9–4.7 in). These images are currently under analysis and could show either an unknown species or an adult individual Galiteuthis glacialis Squid, or the first ever footage of a small juvenile colossal squid. It appears at the 2 minute 33 second mark in the video below.
“The colossal squid is an outsized poster child for how little we know about the ocean,” Matt Mulrennan, Marine Scientist, leader of four 2022-2023 expeditions and founder/CEO of the nonprofit Kolossal, said in a statement sent to IFLScience.
Glass squid are scientifically known as the Cranchiidae family, which includes both the colossal squid and Galiteuthis glacialiwith species belongs. These are the only Cranchidae known to live in these Antarctic conditions.
“The two known taxa of Cranchiidae observed in Antarctica are.” Galiteuthis glacialis and Mesonychoteuthis hamiltoni. The octopuses we see here could belong to different life stages of both of these taxa – and it’s an exciting example of wild cranchiid behavior, as I can’t think of any existing video footage of either of these octopuses in their natural habitat,” said Dr Aaron Evans. who studies the family Cranchiidae and viewed the footage.
The footage shows large amounts of marine snow, which is organic matter falling into the ocean depths; this obscures the view of the mysterious octopus it seems.
“Identifying glass octopuses from footage can be tricky; some species have unique combinations of visible features, but other groups of species look so similar that it is very difficult to confirm who it is just from pictures,” said Dr. Kat Bolstad from Auckland University of Technology (AUT), who is an expert on colossal octopuses, also viewed the footage.
In addition to the octopus footage, the team filmed a whole host of other deep-sea creatures – more than 80 different species, including giant volcanic sponges, Antarctic sun stars and many species of tunicates, soft corals, siphonophores and crinoids.
Giant volcanic mushrooms are believed to be the oldest living animals in the world, with lifespans estimated at up to 15,000 years.
Image credit: © KOLOSSAL / MULRENNAN
“This sighting of the glass octopus adds to 100 years of mystery surrounding the search for the colossal octopus, as the true identification may ultimately never be known. But during these exciting expeditions, we also engaged many people – from students to retirees – in the spirit of ocean exploration and discovered that the remote watery depths of Antarctica are alive, unique and worthy of protection,” concluded Mulrennan.