It’s being called the ultimate deep-sea throwback — a creature that bridges 300 million years of evolution. The mysterious ‘vampire squid from hell’ has unveiled something astonishing: the largest cephalopod genome ever mapped, containing over 11 billion base pairs. To put that in perspective, that’s more than double the size of the biggest known squid genome — a true genetic leviathan lurking in the deep.
But hidden in this gargantuan code of A, T, G, and C lies an even more intriguing revelation. Despite its misleading name, the species Vampyroteuthis infernalis isn’t a true squid. Yet, its chromosomes still echo the structure shared with the ancient ancestor common to modern squids and octopuses. In other words, this strange creature carries a genetic blueprint that time almost forgot.
The vampire squid is a living paradox perched on a lonely branch of the cephalopod family tree. It’s not a squid, not an octopus, and certainly not a vampire — but rather the last survivor of a lineage that once thrived and then faded away into history. Think of it as an evolutionary ghost, quietly drifting through the dark depths of the ocean, holding secrets from an era when dinosaurs had yet to roam.
Some scientists even refer to it as a ‘living fossil.’ Fossil evidence suggests its lineage dates back more than 183 million years. Despite adapting to modern conditions, it still retains primitive features from its ancient ancestors — proof of how evolution sometimes favors preservation over change. Living thousands of feet below the ocean surface, this deep-sea drifter scavenges in darkness while carrying remnants of a prehistoric past.
Its physical traits — and now its DNA — hint that it might be the missing genetic link scientists have long sought. By analyzing these vestiges shared with squids, octopuses, and cuttlefish, researchers can peer into what the earliest cephalopod ancestors might have looked like before these species evolved in their own directions nearly 300 million years ago.
As genomicist Oleg Simakov from the University of Vienna explains, “The vampire squid sits right at the interface between octopuses and squids. Its genome reveals deep evolutionary secrets on how two strikingly different lineages could emerge from a shared ancestor.” And this is where it gets controversial — if its genome really bridges squids and octopuses, what does that mean for how we classify life in the deep today?
Collecting a specimen wasn’t easy. The vampire squid dwells in extreme depths of over 600 meters (about 2,000 feet), where pressure and darkness make human exploration nearly impossible. Luckily, researchers obtained one accidentally, caught as bycatch by the Tokai University vessel T/V Hokuto during a research mission in Suruga Bay.
When scientists sequenced its genome, they were floored: it measured a staggering 11–14 gigabases. For comparison, the longfin inshore squid’s genome is just 4.4 gigabases, the Hawaiian bobtail squid’s is 4.9, and the previous cephalopod heavyweight, the common cuttlefish, tops out at 5.5. Even octopus species are dwarfed by this data trove, with genome sizes ranging between 2.2 and 2.7 gigabases depending on the species. The vampire squid’s genome is not just large — it’s monumental.
Even more surprising is that roughly 62 percent of that genome is made up of repetitive DNA — stretches of genetic code that repeat endlessly without adding much new information. These sequences dramatically inflate genome size, acting almost like an evolutionary echo chamber.
To understand what this meant, scientists compared the vampire squid’s genome to those of other cephalopods — including squids, octopuses, cuttlefishes, and even the nautilus. They also sequenced another oddball species: the muddy argonaut, a type of octopus whose females carry an external shell. The results were unexpected. Despite being an eight-armed ‘octopodiform,’ the vampire squid retains fragments of chromosomal structure seen in ten-armed relatives known as decapodiforms. This suggests its chromosomes have remained relatively unchanged through millions of years, faithfully preserving a genetic link to its ancient kin.
In contrast, octopuses appear to have taken a different evolutionary turn. Early in their history, they underwent a dramatic process known as fusion-with-mixing — where chromosomes not only fused but also intermingled genetically, leading to new traits and biological flexibility. This process may explain why octopuses are often hailed as the most behaviorally complex of all invertebrates.
So, while octopuses evolved through intense chromosomal reshuffling, the vampire squid seems to have stood still, preserving a kind of primal DNA time capsule. This unique stability, researchers believe, makes it an invaluable reference point — almost like a Rosetta Stone — for decoding how today’s cephalopods came to be.
As genomicist Emese Tóth puts it, “The vampire squid retains a genetic heritage that predates both squid and octopus lineages. It gives us a direct look into the earliest stages of cephalopod evolution.”
The findings, published in iScience, underscore how evolution often hides its greatest stories in the least likely of creatures — those quietly surviving in the shadows of Earth’s oldest seas. But here’s a question to ponder: if the vampire squid has changed so little in nearly 200 million years, does that mean evolution favors complexity — or endurance? Which would you bet on?
