We’ve known about the colossal squid for nearly 150 years. Zoologist Japetus Steenstrup first reported on the species in 1857 after reading reports of it washing up on ocean shores.

But there’s still a lot that we don’t know about it because it’s so hard to study. Its reproductive patterns, mating and hunting patterns are still largely unknown because we hardly ever see it in action. Nonetheless, ever since Twenty Thousand Leagues Under the Seas, we’ve been captivated by this supersized cephalopod.

How Big Is a Colossal Squid?

As long as a semi-truck and weighing as much as a ton — the colossal squid lives up to its name. With a massive beak and eyes the size of a human head, this enormous animal with eight arms and two extra-long tentacles has mainly remained elusive for much of human history.

But in recent years, as humans have become better equipped to dive deeper into vast swaths of unchartered oceans, we’ve enjoyed a few colossal squid sightings. 

Colossal Squids vs. Giant Squids

Most of what we know about the colossal squid comes from the dead creatures that wash up on our shores. While there is little video evidence, there is some footage of giant squids. These squids can get confused for colossal squids, but they are two different species.

A rare video caught on tape by divers off the coast of Japan showed a giant squid in all its glory. Another sighting in the Gulf of Mexico in 2019 showed a giant squid attacking an underwater camera designed to track it.

Read More: Sneaky Deep-Sea Camera Captures Footage of Elusive Giant Squid

Where Do Colossal Squids Live?

This member of the cephalopod family (along with smaller squids and octopuses) is famously hard to spot. And part of the reason why is that they live at such deep depths, between 1,000 and 2,000 feet in the dark and cold ocean.

And considering how few sightings there have been, it’s also likely that they’re a rare species. 

Colossal Squid Eyes

The colossal squid also has some of the largest eyes in the animal kingdom due to its need to hunt in the deep, dark ocean where sunlight can’t reach. Its enormous eyeballs are capable of picking up even the tiniest amounts of light.

There’s a lot we don’t know about the creature because it’s so hard to spot and because its habitat in the waters off of Antarctica is less visited by humans. However, it comes farther north to feed.

Read More: Squid Camouflage Inspires Human Invisibility: Is it Possible?

What Do Colossal Squids Eat? And What Eats Them?

While these giant creatures are fearsome to humans, we’re not their prey. They’d prefer to nosh on fish, large and small, including the Patagonian toothfish — a fish found in cold waters with rows of canine-like teeth that give it its name.

We also know that it’s an ambush predator, which means it sits and waits for a good opportunity to attack its prey and catch them by surprise. It grabs its prey with its tentacles, equipped with suckers that are about 5 cm ( about 2 inches) in diameter and have built-in serrated “teeth” that are sharp and sticky. Its prey doesn’t stand a chance.

We know less about what the squid eats compared to what eats it because sightings of it hunting are rare. But it’s thought that colossal squid makes up at least 77 percent of a sperm whale’s diet. The epic battles between the colossal squid and the sperm whale show that when the sperm whale is ready for a meal, the squid isn’t always ready for the taking.

As a result, many sperm whales are covered in pockmarks from death battles with this giant suctioned beast. Still, in the end, the massive sperm whale — the largest living member of the toothed whale genus — usually wins.

Read More: A New Whale Species Is Fighting for Survival