Giant Octopuses Ruled Ancient Seas 100 Million Years Ago

Scientists just discovered that massive octopuses the length of bowling lanes were apex predators when dinosaurs walked the Earth, completely changing what we thought we knew about ancient oceans.

Researchers at Hokkaido University in Japan found fossils of octopuses called Nanaimoteuthis that measured up to 62 feet long and ruled the seas between 100 and 72 million years ago. Their discovery, published in the journal Science, reveals these colossal creatures had powerful jaws that show intense wear from crushing hard prey like shells and bones.

"We were surprised," said study coauthor Yasuhiro Iba. "The fossil record of octopuses is extremely limited, so finding animals this large and ecologically important in the Cretaceous ocean was beyond our expectations."

The team analyzed 15 huge jaw fossils from Japan and Canada's Vancouver Island, then used cutting-edge technology to find 12 more specimens hidden inside solid rock. They employed a technique called grinding tomography paired with an AI model to create detailed 3D images of the fossils, a method Iba calls "digital fossil mining."

Finding octopus fossils is incredibly rare because their bodies are almost entirely soft tissue. Only their hard beaks typically survive after death, making this discovery particularly remarkable.

Until now, scientists believed only vertebrate predators like marine reptiles, sharks, and large fish commanded the ancient seas. These octopuses suggest ocean ecosystems during the Cretaceous Period were far more complex and diverse than previously thought.

Why This Inspires

This discovery shows how new technology can reveal hidden chapters of Earth's story that seemed lost forever. The same AI and imaging tools helping us understand our past are opening doors to discoveries we never imagined possible.

Like modern octopuses, these ancient giants likely used intelligence to hunt their prey. The asymmetrical wear patterns on their jaws hint at sophisticated feeding behaviors that required real problem-solving skills.

Tim Coulson, a professor of zoology at the University of Oxford who reviewed the study, called the work "compelling and exciting." He noted these creatures could crunch through bones of large fish and possibly marine reptiles, cementing their position at the top of the food chain.

Iba plans to expand digital fossil mining to uncover more hidden organisms from ancient ecosystems. "Our goal is to reveal the hidden players of ancient ecosystems and build a much more complete picture of how past ecosystems really worked," he said.

The ocean still holds countless secrets waiting to be discovered, and now we have better tools than ever to find them.