New fossil research suggests that some of the earliest octopuses were far larger and more formidable than modern species. According to a study published in Science, two Cretaceous octopus species may have grown to extraordinary sizes and occupied a top position in ancient marine ecosystems.
Ancient Giants in the Sea
Researchers examined 27 fossil octobrachian jaws, including 12 newly identified specimens analyzed through high-resolution tomography and an AI-assisted digital fossil search. The findings point to Nanaimoteuthis haggarti and N. jeletzkyi as massive finned octopuses that could have reached lengths of about 18.6 meters and 7.7 meters, respectively.
The jaw fossils show chips, scratches, polishing, and uneven wear, patterns that match animals adapted to crushing hard prey such as shells, crustaceans, and bone. In the largest species, researchers estimate that jaw wear may have reduced total length by around 10 percent over time.
Clues to Behavior and Intelligence
One of the most intriguing details is the asymmetrical wear seen on the jaws, with the right side more worn than the left. The team suggests this may reflect lateralized feeding behavior, a possible sign of advanced neural control. While fossil wear cannot reveal thought directly, the pattern adds a new layer to the story of octopus evolution.
The study challenges the idea that Cretaceous seas were dominated only by large vertebrate predators. Instead, these ancient octopuses may have combined size, strength, and behavioral flexibility to thrive alongside marine reptiles and other major ocean hunters.
If confirmed by future discoveries, this research could reshape how scientists view the rise of complex life in ancient oceans and the long evolutionary path of cephalopod intelligence.