For the first time since its discovery a century ago, what will grow up to become one of the heaviest invertebrates on the planet has been caught on video in its natural habitat.

Growing up to seven metres in length, the colossal squid – known as Mesonychoteuthis hamiltoni, first identified in 1925 when the remains of one’s heads and arms were discovered in a sperm whale’s stomach – can weigh up to half a tonne, making the species the heaviest invertebrate in the world.

Although it was discovered 100 years ago, much about the colossal squid has remained a mystery. Until the Schmidt Ocean Institute released footage of a juvenile colossal squid swimming in the deep sea this week, none had ever been filmed alive in the wild.

Why this baby squid’s small-screen debut is so colossal

Taken by a team of international researchers and scientists aboard Schmidt Ocean Institute’s research vessel, Falkor, the video shows the colossal squid – semi-transparent, with eight arms – swimming in the deep sea near the South Sandwich Islands (an island east of the Falkland Islands), about 600 metres below the South Atlantic Ocean’s surface, on March 9.

Loading

At the time, those aboard Falkor had no idea they were filming a colossal squid. It’s only 30 centimetres in length, indicating the squid caught on camera – it was captured by SuBastian, a remotely operated vehicle, during a 35-day expedition looking for new marine life – was just a baby. Days later, independent scientific experts verified the squid was, in fact, a colossal, thanks to the sharp hooks on its tentacles, which distinguishes it from other species of glass squid.

“These unforgettable moments continue to remind us that the ocean is brimming with mysteries yet to be solved,” Schmidt Ocean Institute executive director Jyotika Virmani said.

What little we do know about the colossal squid