Not just folklore: A giant kraken-like octopus terrorized the seas in the age of dinosaurs

The giant kraken, a mythical marine beast, may not be entirely fiction. New evidence suggests that octopuses up to 62 feet long likely roamed the waters of ancient Earth, ripping and devouring prey in their path.

Monster under the sea

These gigantic octopuses might have been formidable predators of the ocean approximately 100 million years ago, according to a study published in the journal Science. “With their large bodies, long arms, powerful jaws and advanced behavior, they represent what could be described as a real Cretaceous Kraken,” said Yasuhiro Iba, a paleontologist at Hokkaido University in Japan and the lead author of the study, to Reuters. The invertebrates would have "rivaled” and “possibly even preyed upon apex predators such as mosasaurs and plesiosaurs,” said The Guardian.

Though octopuses are some of Earth’s oldest animals, they are difficult to study from the past, because they lack hard external shells and have very few fossils. So researchers studied the fossilized beaks of the animals, revealing two extinct species: Nanaimoteuthis jeletzkyi and Nanaimoteuthis haggarti. The beaks and jaws were used to deduce the size of the creatures, between 23 and 62 feet, as well as their feeding habits.

The jaws showed "signs of intensive wear, with patterns indicating that these animals were dismantling hard-shelled prey,” said Live Science (a sister site of The Week). “To see a beak this size is quite amazing, to be honest. It was a massive animal,” said Thomas Clements, a palaeobiologist at the University of Reading, to The Guardian. “I certainly wouldn’t have wanted to go swimming in the ancient oceans if these things were swimming around.”

Large and in charge

The octopuses of today are notoriously intelligent, and that was likely the case in the past, as well. The researchers found that the octopuses’ jaws were “ground down on one side by as much as 10% of their total size, based on reconstructions,” said Live Science. This “lopsided loss suggests lateralized behavior, which is linked to being brainier.”

“Some of those remarkable traits” that are also present in the modern-day creatures “may already have been emerging in early octopuses during the Cretaceous,” said Iba to NPR. Along with intelligence, ancient octopuses probably also used their strong tentacles to rip prey apart before eating it, similar to modern octopuses’ hunting patterns.

“For roughly the past 370 million years, marine ​ecosystems have been thought to be dominated by large vertebrate predators — first fishes and sharks, then marine reptiles and later whales,” said Iba. “Giant invertebrates, namely octopuses, also functioned as apex predators in the Cretaceous sea,” according to the research.

However, there may be some inaccuracies in the findings because the researchers used “error-prone” methods in estimating the size of the octopuses and produced the largest possible size range for them, said René Hoffmann, a paleontologist focusing on fossil cephalopods at the Ruhr University Bochum in Germany, to Live Science. Their size also doesn’t necessarily mean that the octopuses were apex predators.

Despite this, the results provide valuable new information about the ancient animals. “It’s a big old planet,” said Neil Landman, a paleontologist at the American Museum of Natural History in New York, to The Associated Press. “So we have lots to look at to piece together the marine ecosystem through time.”