500 Kilos of Mystery: What We Still Don’t Know About the Colossal Squid

Imagine a creature so massive it can weigh over 500 kilograms, with eyes the size of dinner plates and tentacles armed with rotating hooks. It sounds like something straight out of a science fiction thriller. Yet, this monster is real—and it's lurking in the freezing depths of the Southern Ocean.

Colossal Squid

The colossal squid (Mesonychoteuthis hamiltoni) is one of the most mysterious and elusive creatures on Earth. First identified in 1925 through remains found in the stomach of a sperm whale, this deep-sea giant has managed to keep much of its life hidden. Despite technological advances in ocean exploration, most of what we know about the colossal squid comes from a handful of specimens and the scars they leave on their predators.

This article takes a deep dive into the mysteries we still haven't solved about the colossal squid and why this enigmatic invertebrate continues to fascinate scientists and ocean lovers alike.

1. What Does a Colossal Squid Actually Look Like in the Wild?

Despite its fearsome reputation, no one has ever seen a colossal squid alive in its natural habitat. Our understanding of its appearance is based on dead specimens, often damaged or decomposed. While we know they can reach lengths of 10 to 14 meters (up to 46 feet), their shape and coloration in the wild remain speculative.

Do they change color like other squid? Do they glow with bioluminescent patterns? What is their true skin texture and movement style? These remain open questions, waiting for that first lucky underwater encounter.

2. How Many Colossal Squids Are Out There?

Population size is a fundamental part of understanding any species—but in the case of the colossal squid, it's an educated guess at best. The Southern Ocean is vast and largely unexplored, and the squid’s deep-sea lifestyle makes it nearly invisible to traditional observation techniques.

Some scientists suggest they may be relatively common, given how frequently sperm whales seem to encounter them. Yet others believe they are rare giants, sparsely scattered throughout the deep. Until we develop better deep-sea tracking methods, their true numbers remain hidden in the dark.

3. How Do They Hunt?

One of the most tantalizing mysteries is how the colossal squid hunts. Unlike their cousins, the giant squid (Architeuthis dux), which are believed to be active hunters, the colossal squid may be ambush predators. The theory is based on their slow metabolism, suggesting they may use stealth and surprise to capture prey rather than speed.

But what exactly do they eat? While fish like Patagonian toothfish are on the menu, scientists still don’t have a full picture of their diet. Their tentacles are equipped with swiveling, razor-sharp hooks, indicating they’re well adapted to grabbing and subduing powerful prey—yet how often, and how successfully, they feed is still unknown.

4. How Do They Mate and Reproduce?

Perhaps the biggest mystery surrounding the colossal squid is its reproductive cycle. No one has ever seen a colossal squid mate, lay eggs, or hatch. Scientists assume that, like other cephalopods, they engage in a brief mating ritual and then die soon after. But this is pure speculation.

Even the question of where they reproduce is unknown. It could be near the seafloor, in deep-sea trenches, or even under Antarctic ice shelves. The absence of juvenile specimens in scientific records raises more questions than answers. Where are the baby colossal squids?

5. How Long Do They Live?

Age estimation in deep-sea animals is notoriously difficult, and the colossal squid is no exception. Some scientists believe they may live less than two years, while others suggest a lifespan closer to ten or more.

Their slow growth rate and immense size suggest they may age more like whales than other invertebrates. But without the ability to tag and track individuals over time, this remains an unanswered question. We don’t even know what aging signs to look for in a squid of this size.

6. Do They Have Natural Camouflage or Bioluminescence?

Many squid species have evolved bioluminescent organs to help them hunt, evade predators, or attract mates. In some captured specimens of the colossal squid, scientists have found photophores—light-producing organs. However, their function in the colossal squid remains unclear.

Do they use these lights to lure prey, confuse predators, or communicate? And do they possess chromatophores—the color-changing cells used for camouflage in other squids? Without live observation, we may never know how this mysterious behemoth interacts visually with its environment.

7. What Is Their Role in the Ecosystem?

Every apex predator has an ecological role. But what role does the colossal squid play? We know they are a major food source for sperm whales, who dive deep to engage in life-or-death battles with them. But aside from that, their impact on mid- to deep-ocean ecosystems remains murky.

Could their presence influence populations of mid-sized fish or other squids? Are they responsible for balancing prey species or affecting food chain dynamics? We simply don’t have the data.

8. Why Don’t We See Them More Often?

The colossal squid is not only elusive but also lives in one of the most inaccessible regions of the planet—the cold, crushing depths of the Southern Ocean around Antarctica. These regions are difficult and expensive to explore.

Add to that their likely solitary nature, low activity level, and perhaps specific migratory or reproductive zones, and it's no wonder we haven’t encountered more of them. Even advanced deep-sea submersibles and robotic explorers have failed to capture a single confirmed live sighting.

9. What Makes Them So Different from the Giant Squid?

Often confused with the giant squid, the colossal squid is actually a completely different species. While the giant squid is long and more slender, the colossal squid is shorter but heavier, broader, and equipped with hooks instead of suction cups.

But why did these two species evolve so differently? What environmental pressures or evolutionary paths led to one becoming long and tentacle-like, and the other turning into a dense, compact tank of a squid? This divergence holds clues not just to squid evolution but to deep-sea adaptation itself.

10. How Much Don’t We Know?

Here's the truth: we know more about the surface of Mars than we do about the deep ocean. And when it comes to colossal squid, our knowledge is based on a few dead specimens, a handful of theories, and a lot of guesswork.

There may be entirely unknown behaviors, biological processes, or even abilities that we’ve never imagined. Could they communicate through electrical signals? Do they have social interactions we can’t detect? Could their nervous system or intelligence levels rival those of octopuses?

The lack of data makes every hypothesis both exciting and frustrating. It’s a reminder that Earth still holds ancient, unsolved mysteries—especially in the dark, cold world beneath the waves.

Why the Mystery Matters

You might wonder: why should we care about an elusive sea monster that few will ever see?

The answer is that understanding the colossal squid can teach us more than just biology. It can reveal:

• How life adapts to extreme environments
• The limits of evolution and size in invertebrates
• The complex food webs of deep-sea ecosystems
• How much we still have to learn about our own planet

In a world where satellites orbit planets millions of miles away, it’s humbling to know that here, on Earth, a 500-kilo creature remains largely invisible to us.

The Kraken Lives On

For centuries, sailors spoke of sea monsters—the Kraken, the Leviathan, great beasts with tentacles that pulled ships under the sea. As it turns out, they weren't entirely wrong.

The colossal squid is a real-life myth, a being of legend that has stepped—however reluctantly—into the scientific spotlight. But unlike myths, the colossal squid has not been fully explained, categorized, or understood. It continues to resist easy answers.

Until we invent better deep-sea exploration technology, or until fate delivers another rare specimen to our hands, the colossal squid will remain what it has always been:

A 500-kilo mystery wrapped in arms and secrets, swimming silently through the dark.