Researchers have uncovered evidence that octopuses from the Late Cretaceous period, around 100 million years ago, grew to lengths of nearly 20 meters and hunted as top predators. The findings, based on well-preserved fossil jaws from Japan and Vancouver Island, challenge previous views of early octopus evolution. Professor Yasuhiro Iba of Hokkaido University led the study, published in Science on April 23.
Scientists at Hokkaido University analyzed fossilized jaws embedded in rocks from the Late Cretaceous, dating between 100 and 72 million years ago. Using high-resolution grinding tomography and an artificial intelligence model, they examined specimens from an extinct group of finned octopuses called Cirrata. The jaws showed extensive wear—chipping, scratching, and polishing—indicating powerful bites used to crush hard-shelled prey, far exceeding that seen in modern cephalopods. Uneven wear patterns suggested lateralization, a trait linked to advanced brain function in contemporary animals.Professor Yasuhiro Iba stated, 'Our findings suggest that the earliest octopuses were gigantic predators that occupied the top of the marine food chain in the Cretaceous.' He noted that these creatures may have reached total lengths of up to nearly 20 meters, potentially surpassing large marine reptiles of the era. Iba added, 'The most surprising finding perhaps was the extent of wear on the jaws,' with up to 10% of the jaw tip worn away in mature specimens, pointing to repeated forceful interactions with prey.The discovery pushes back the known origins of finned octopuses by about 15 million years and octopuses overall by around 5 million years. It provides the first direct evidence that invertebrates could become giant, intelligent apex predators in vertebrate-dominated oceans. Iba explained, 'Powerful jaws and the loss of superficial skeletons... were essential to becoming huge, intelligent marine predators.'This research highlights new digital techniques for uncovering hidden fossils, potentially revealing more about ancient marine ecosystems.