May 9, 2026 · Tags: ocean, science, marine biology, colossal squid, sperm whales, deep sea, eDNA
A TikTok by science journalist Cleo Abram recently made some bold claims about sperm whales and colossal squid — that 80% of a sperm whale's diet is colossal squid, that these squid grow to 9 meters, and that scientists are using "a drop of water" to track them down. I went down the rabbit hole. Here's what checks out, what doesn't, and what's way weirder than the video let on.
The 80% Diet Claim #
The video says ~80% of a sperm whale's diet is colossal squid. The real number is 77% by biomass — and it's specific to Antarctic sperm whales, not the species globally.
Here's how scientists arrived at that figure: sperm whale stomachs contain thousands of squid beaks (the hard, chitinous parts that don't digest). Colossal squid beaks make up only 14% of the number of beaks found. But because each colossal squid is so massive — up to 500 kg — that 14% by count translates to 77% by weight. A healthy sperm whale eats 1 to 1.5 tonnes of food per day. That's a staggering amount of squid.
The picture changes dramatically outside Antarctic waters. A 1993 study of sperm whales near the Azores found their diet was dominated by much smaller squid families — Octopoteuthidae (39.8%), Histioteuthidae (32.7%), and Architeuthidae (12.1%). Colossal squid don't even appear. So the 80% figure is real, but only for the whales that live next door to the colossal squid's Antarctic range.
The 9-Meter Length Claim #
This one's complicated. The largest measured colossal squid was a 495 kg female caught in 2007 by a New Zealand fishing vessel in the Ross Sea. When thawed and measured at Te Papa museum, she came in at 4.2 meters total length — but her tentacles had shrunken after death. If you include extended tentacles on a living animal, estimates range from 6–7 meters conservatively (CEPH REF, Rosa et al. 2017) to 10–14 meters (Britannica, some scaling analyses).
So 9 meters is plausible but unconfirmed. No living adult has ever been fully measured in the water. We're extrapolating from dead specimens and beaks found in whale stomachs.
What we do know: the colossal squid has the largest eyes of any known animal — up to 27–30 cm across, roughly the size of a dinner plate. Those eyes likely evolved to detect the faint bioluminescent disturbances caused by approaching sperm whales in the pitch-black deep.
The First Footage #
This one checks out completely, and it's a genuinely historic moment. On March 9, 2025, the Schmidt Ocean Institute's remotely operated vehicle SuBastian filmed a 30 cm juvenile colossal squid at 600 meters depth near the South Sandwich Islands in the South Atlantic. An online viewer watching the live dive stream flagged the sighting, and independent squid experts Kat Bolstad (Auckland University of Technology) and Aaron Evans confirmed the identification based on visible mid-arm hooks — a feature unique to colossal squid among glass squids.
This was the first confirmed live observation of Mesonychoteuthis hamiltoni in its natural habitat — exactly 100 years after the species was first described from tentacle remains found in a sperm whale stomach in 1925.
The footage is striking. Bolstad described the juvenile as looking "like a glass sculpture" — translucent, delicate, with large rusty-red chromatophores (color-changing cells) on its mantle. It's a world away from the fearsome deep-sea monster of popular imagination.
The "Drop of Water" Claim #
Environmental DNA (eDNA) is a real and rapidly advancing technique. Organisms constantly shed genetic material — skin cells, mucus, waste — into surrounding water. By filtering seawater and running PCR analysis, scientists can detect species-specific DNA signatures without ever seeing the animal.
It's been used successfully for cephalopods: a 2020 study detected giant squid (Architeuthis dux) eDNA in the Sea of Japan, and a 2026 study by Curtin University and the WA Museum found giant squid traces off Western Australia's Ningaloo Coast — the first detection there in over 25 years. That study analyzed over 1,000 water samples and identified 226 species.
But here's the catch: no published study has used eDNA specifically to detect colossal squid yet. The technique is proven for their cousin, the giant squid, and is widely regarded as the most promising tool for locating elusive deep-sea species. The video's claim is forward-looking — eDNA is being developed as a method that could find colossal squid, not one that has already done so.
The Stuff the Video Didn't Mention #
The scars tell the story #
Sperm whales bear circular scars on their skin and backs from colossal squid suckers and hooks. These aren't gentle grazes — colossal squid tentacles have 22–25 rotating hooks that can swivel 360 degrees, locking onto prey with mechanical precision. The arms have additional fixed hooks in double rows, with serrated suckers surrounding them. Toothfish caught on longlines sometimes show circular wound marks from these suckers.
They're ambush predators, not chasers #
Despite their terrifying weaponry, colossal squid probably don't chase anything. Their metabolism is remarkably slow — estimated at just 30 grams of food per day (Rosa & Seibel, 2010). Steve O'Shea, who coined the name "colossal squid," now believes they're more like "giant gelatinous ticks, simply blobbing around in the water column near the seabed." Their massive eyes aren't for hunting prey at long distances — they're for detecting predators (read: sperm whales) before those predators get close enough to eat them.
A 5-year life of explosive growth #
Colossal squid exhibit abyssal gigantism — they grow extremely fast in cold, deep water. A 2024 study estimated their maximum lifespan at just 5.2 years based on growth increments in their beaks. In that brief window, they go from tiny hatchlings in surface waters to multi-meter giants in the deep ocean, undergoing what researchers call "ontogenetic descent" — a gradual migration from shallow to deep as they grow.
We've never seen a mature adult alive #
As of 2026, a total of only eight adult colossal squid have ever been reported. Six of those were remains recovered from sperm whale stomachs. The other two were caught on fishing lines. No mature adult has been observed alive in the water. The 2025 footage is a juvenile — exciting because it fills a gap in our understanding of the species' middle life stages, but the adults remain completely mysterious.
One more thing — the glacial glass squid #
During a separate January 2025 expedition near Antarctica, the same Schmidt Ocean Institute team captured the first confirmed footage of the glacial glass squid (Galiteuthis glacialis) at 687 meters in the Bellingshausen Sea. Two first-ever sightings of deep-sea cephalopods in a single expedition year. The deep ocean is giving up its secrets slowly.
Why This Matters #
The colossal squid is a reminder of how much we don't know about our own planet. The largest invertebrate on Earth — a half-tonne predator with dinner-plate eyes and rotating hooks — was only identified 100 years ago from digested remains in a whale's stomach. We've seen exactly one living juvenile, for a few minutes, on a single dive.
The tools are catching up. ROVs with low-light cameras. eDNA water sampling. Live-streamed dives that let anyone in the world watch. But the Southern Ocean is vast, deep, and brutally cold. The research vessel that filmed the 2025 juvenile won't return to Antarctic waters until 2028.
Until then, sperm whales remain our best source of information about colossal squid. They're better at finding them than we are.
Sources: CNN, BBC Future, National Geographic, Ocean Census, Te Papa Museum, Remeslo et al. (2019) Deep Sea Research Part I, Rosa et al. (2017) Polar Biology, Rosa & Seibel (2010), Wada et al. (2020) Marine Biology, Curtin University/WA Museum (2026) Environmental DNA, CEPH REF