During centuries, the figure of the kraken It was considered little more than a sailor's tale about monsters capable of sinking shipsHowever, a series of recent investigations has brought to light something that, until recently, sounded like pure fantasy: giant octopuses up to 19 meters long may have lived in the oceans of the Late Cretaceous, behaving like true super-predators.
These works, published in the scientific journal Science and led by teams from Hokkaido University (Japan)They maintain that certain cephalopods of the extinct genus Nanaimotoeuthis They occupied the top of the food chain between 100 and 72 million years ago. Far from being passive prey, these colossal octopuses would have rivaled mosasaurs, plesiosaurs, and giant sharks for dominance of the seas.
A real kraken in the Cretaceous seas
The new data paint a very different picture from that of classical paleontology, which assumed that large marine vertebrates They were the only kings of the oceanThe Late Cretaceous, situated between about 100 and 66 million years ago, was considered a world dominated almost exclusively by mosasaurs, plesiosaurs, and large sharks.
The study led by researchers such as Shin Ikegami and Yasuhiro Iba demonstrates that in that same period there appeared giant octopuses with elongated bodies, long arms, and extremely powerful jawsThese creatures, integrated into the suborder Cirrata (finned octopuses)They bear a disturbing resemblance to the kraken of Nordic tradition, although they are extinct species with no direct connection to the legends.
Scientists have identified two key species: Nanaimotoeuthis jeletzkyi y Nanaimotoeuthis haggartiBoth are inhabitants of the North Pacific. The first would reach about 7,7 meters in length, while the second could measure between 7 and 19 meters from the tip of the mantle to the end of the tentacles. surpassing even the modern giant squid.
In terms of size, N. haggarti would be at the level of -or above- large marine predators such as Mosasaurus hoffmannii, which was around 17 meters long, or the prehistoric shark Ptychodus mortoni, of about 10 meters. We are therefore talking about some of the largest invertebrates described so far in the fossil record.
The secret lies in the beaks: 27 jaws that change history
Reconstructing the life of a fossil octopus is no easy task. Unlike other marine animals, these cephalopods They lack a bony skeleton and a hard outer shellso its soft body leaves hardly any trace on the rocks. The exception is the chitinous jaws, the famous "beaks," similar to a parrot's beak.
The new work relies precisely on the detailed analysis of 27 fossil jaws from marine sediments in Japan and Vancouver Island (Canada)Some of them were already known, but had been attributed to other groups such as the so-called "vampire squid". Others were located for the first time using a combination of high-resolution tomography and artificial intelligence models.
This “digital fossil mining” allows 3D scan ultrathin layers of rock and detect hidden organic structures without damaging the remains. Thanks to this, the team was able to reconstruct the jaws with great precision, measure their length (in several cases exceeding 80 millimeters) and compare them with those of modern cephalopods to extrapolate the size of the animal.
The data obtained indicate that the peaks of Nanaimotoeuthis In some samples, they exceeded the size of the beak of the modern giant squid, which supports estimates of lengths between 7 and 19 meters. These values place N. haggarti among the largest known invertebrates and force a review of the size scale of Mesozoic predators.
Furthermore, the good state of preservation of the jaws allowed for the study not only of their shape, but also of their surface. Cracks, blunt edges, deep scratches and chips They provide direct information about the diet and lifestyle of these octopuses.
Durophagous superpredators: crushing bones and shells
One of the most striking results of the study is the extreme degree of wear observed in the adult beaks. In young specimens, The tips of the jaws appear sharp as blades.However, in large individuals, these same areas are rounded, eroded, and full of microfractures.
The researchers calculated that some peaks had lost up to 10% of its original length due to constant friction with very hard materialsThe comparison with present-day cephalopods shows a characteristic pattern: it is a wear typical of durophagous animals, that is, predators that feed on prey with bones or rigid shells.
According to the analysis, these giant octopuses They didn't just capture soft-bodied animalsThey were not only capable of crushing ammonite shells and large mollusks, but also the bony skeletons of fish and possibly sizable marine reptiles. Their bite force would have been sufficient to break structures that many other predators would avoid.
To give a simple idea, the authors compare the wear on the beak to that of pruning shears used not to cut leaves, but to break stones: Over time, the sharpness disappears and the edges become deformed.That image illustrates the intensity of predatory activity in Nanaimotoeuthis.
All of this fits with the hypothesis that these cephalopods occupied a trophic level equivalent to that of large marine vertebratesMore than giant prey, they were active superpredators that helped shape the structure of Cretaceous ecosystems.
Enormous size, fins, and life in the open sea
Based on the relationship between beak size and body length in modern cephalopods, scientists estimate that N. jeletzkyi it would be around 7,7 metersWhile N. haggarti It could easily exceed 18 meters, with a likely range between 7 and 19 meters. That's roughly equivalent to an articulated bus or a semi-trailer truck.
The remains analyzed indicate that these animals were part of the suborder Cirrata, Octopuses equipped with small lateral fins that provide them with stable swimmingThat morphology, combined with a long, flexible body, suggests that they were not creatures of the abyssal depths, but inhabitants of continental shelves and relatively open seas in the North Pacific.
Their evolutionary strategy consisted of abandon the protective outer shell which characterized many Mesozoic cephalopods, such as ammonites. By losing that armor, they gained mobility, acceleration, vision, and maneuverability for active hunting, which allowed them to compete directly for large prey.
The models proposed by the team point to a very rapid evolutionary growth in just about 15 million yearsDuring this period, these octopuses grew from moderate sizes to colossal dimensions. This expansion coincided with a period of intense ocean fragmentation following the breakup of Pangaea, which multiplied the available ecological niches.
In this context, Giant octopuses would have shared waters with large mosasaurs, plesiosaurs, and sharkscompeting for the same energy resources. Although no stomach contents have been found that directly prove they attacked mosasaurs, experts believe that, at least in theory, they were within the size and power range necessary to confront large vertebrates.
Intelligence and laterality: clues in the erosion of peaks
Beyond size and brute strength, the study suggests that these animals could be surprisingly sophisticated from a cognitive point of view. The wear observed on the jaws is not uniformThe right side appears systematically more eroded than the left.
This imbalance is reminiscent of the lateralization observed in many modern animals, including present-day octopuses, birds, and mammals, where there is preference for using one side of the body, such as being right-handed or left-handedIn biology, this phenomenon is usually associated with complex nervous systems and elaborate behaviors.
Although the researchers are cautious and admit that Intelligence cannot be measured directly in a fossil.The presence of this asymmetry in the beaks of large individuals supports the idea that Nanaimotoeuthis It wasn't just a giant, clumsy creature. Everything suggests that it preferentially used certain arms to manipulate its prey before delivering the final bite.
This pattern is consistent with the image we have of modern octopuses, known for their learning ability, problem-solving skills, and flexible use of limbsIn the Cretaceous case, this combination of size, power, and possible behavioral sophistication reinforces the idea that they were fully capable of acting as superpredators.
In the words of some specialists consulted in Europe, the idea of encountering an octopus almost 20 meters long armed with a beak capable of crushing bones It's hardly reassuring. Had they coexisted with humans, our ancestors would have had little desire to swim in those seas.
Rewriting the role of invertebrates in prehistoric oceans
For decades, paleontology textbooks have presented Mesozoic marine invertebrates as supporting actors primarily dedicated to defending themselves of large reptiles and sharks. Enlarging shells, reinforcing skeletons, or developing spines were classic strategies for evading predators.
The work on Nanaimotoeuthis This forces a complete rethink of that system. For the first time, it contributes direct evidence of giant invertebrates occupying the top of the food chainnot only as prey, but also as hunters that exert strong pressure on other species.
This change of perspective fits with the idea of convergent evolution: Different groups, vertebrates and invertebrates, develop similar solutions To address the same ecological problem, they became apex predators. While marine reptiles refined their streamlined bodies, giant octopuses opted for flexibility, intelligence, and reinforced jaws.
Thus, the Cretaceous oceans cease to be seen as scenarios where only a few lineages dominated, and become much more competitive and complex ecosystemsThe coexistence of mosasaurs, plesiosaurs, sharks, and giant octopuses suggests a delicate balance, with abundant predator-prey interactions yet to be deciphered.
For European paleontology, which is heavily focused on marine reptiles from the ancient Tethys Sea, these results open the door to review collections of microfossils and rocks already studied in search of cephalopod beaks that might have gone unnoticed. The combination of digital techniques and artificial intelligence could reveal that the Cretaceous “krakens” were not exclusive to the North Pacific.
AI, tomography and digital mining: new tools for tracking krakens
One of the most important methodological contributions of the study is the combined use of high-resolution computed tomography and artificial intelligence to locate tiny fossils in seemingly unremarkable blocks of rock.
Instead of physically extracting the remains, with the risk of damaging them, the researchers scanned the samples layer by layer. Then, an AI model specifically trained to recognize them... patterns characteristic of organic structures, such as the beaks of cephalopods, identified hidden jaws that would have gone unnoticed with conventional techniques.
This approach, which is already beginning to be implemented in laboratories in Europe, allows for the reconstruction detailed 3D models in full color of the fossils without needing to remove the rock matrix. In addition, it facilitates the study of surface wear with a level of detail that was previously unthinkable.
Beyond the specific case of NanaimotoeuthisThese tools open a path to rediscover ancient ecosystems with a fresh perspectiveMany sites preserve soft or fragmentary fossils embedded in the rock that could be brought to light thanks to this type of "digital archaeology".
This technological approach is already generating interest among European teams working in Cretaceous deposits of the Iberian Peninsula and the rest of the continentAlthough no giant octopus findings have been announced so far in waters that today would correspond to the eastern Atlantic or the early Mediterranean, no one rules out that future campaigns will reveal surprises.
From Norse myth to modern paleontology
The connection between science and the myth of the kraken is one of the aspects that has most captured the public's attention. For sailors from Northern Europe, The kraken was a colossal creature, often described as a giant octopus or squid., capable of wrapping ships with its tentacles and dragging them to the bottom.
Traditionally, scientists had linked these legends with sporadic sightings of giant squidThese creatures, known for decades, can reach lengths of around 12 meters. However, new data suggests that nature produced even more impressive creatures, albeit millions of years before those accounts existed.
The authors of the study clarify that There is no direct historical relationship between Cretaceous octopuses and Viking sagas.separated by a vast temporal chasm. But they admit that the similarity in size and lifestyle—large, soft-bodied predators with long tentacles—makes the comparison inevitable.
In statements reported by various media outlets, several paleobiologists agree that Nature has given rise in the past to animals that closely resemble what we imagine today as a krakenThe discovery of Nanaimotoeuthis It demonstrates that the line separating fiction and reality is sometimes thinner than it seems.
For the scientific community, this case also serves as a reminder of how incomplete the fossil record still isEach new fossil, however small, that is well studied can force a revision of stories that seemed closed, from the evolution of cephalopods to the structure of past marine ecosystems.
The picture that emerges from these studies is one of Cretaceous oceans that were far more dangerous and varied than previously thought, where Giant octopuses up to 19 meters long shared the spotlight with marine reptiles and sharksFrom a handful of fossilized jaws, paleontology has brought to light enormous invertebrates, probably intelligent and capable of crushing bones and shells without much trouble, which fit surprisingly well with the popular idea of a "real kraken" and remind us to what extent the seas of the past still hold secrets of colossal proportions.
