Giant octopuses may have ruled the oceans 100 million years ago

Today's octopuses are intelligent, remarkably flexible animals that lurk in reefs, hide in crevices, or drift through the deep sea. The institutional report frames the development in practical terms and ties it to the broader mission or observing effort.

This matters because Earth science becomes stronger when local observations can be placed inside a broader physical pattern that spans time and geography. The planet operates as a coupled system in which atmospheric, oceanic, cryospheric and solid-Earth processes interact across timescales from days to millions of years. A measurement that captures one variable at one location and one moment has limited interpretive value until it is embedded in the longer series and wider spatial coverage that allow natural variability to be separated from forced change. The study is published in Science. Edited by Stephanie Baum, reviewed by Robert Egan This article has been reviewed according to Science X's editorial process and policies.

Yohei Utsuki, Department of Earth and Planetary Sciences, Hokkaido University Today's octopuses are intelligent, remarkably flexible animals that lurk in reefs, hide in crevices. But new research suggests that their earliest relatives may have played a far more predatory role in ocean ecosystems.

Using high-resolution grinding tomography and an artificial intelligence model, they found fossil jaws hidden inside rock samples from the Late Cretaceous period, spanning 100. Based on exceptionally well-preserved fossil jaws, we show that these animals reached total lengths of up to nearly 20 meters, which may have surpassed the size of large marine.

In well-grown specimens, up to 10% of the jaw tip relative to the total jaw length had been worn away, which is larger than that seen in modern cephalopods that feed on. This indicates repeated, forceful interactions with their prey, revealing an unexpectedly aggressive feeding strategy.

The broader interest lies in linking the observation to climatic, geophysical or environmental dynamics that extend well beyond the immediate event or location. Earth science is unusual in that its most important questions operate on timescales that no single research career can observe directly, making the archival record, whether in ice, sediment, rock or satellite data, as important as any new measurement. Results that can be embedded in that record, and that either confirm or challenge the patterns it reveals, carry disproportionate scientific weight.

The new fossils extend the earliest known record of finned octopuses by around 15 million years and the broader octopus record by around 5 million years, placing them as far back. The new findings suggest that giant octopuses were an unexpected exception: invertebrates that rose to the top tier of the marine food web and competed with large vertebrates.

Because the account originates with Phys. org Biology, it functions best as a primary institutional report that is close to the data and operations, not as independent scientific validation. Institutional communications are produced by organizations with legitimate interests in presenting their work in a favorable light, which does not make them unreliable but does make them partial. Details that complicate the narrative, including instrument limitations, unexpected failures and results below projections, tend to be minimized relative to progress messages. Technical documentation and peer-reviewed publications, where they exist, provide the complementary layer that institutional releases cannot substitute.

The next step is to place the result inside longer time series and to compare it with independent instruments and independent sites. Earth system observations gain most of their interpretive power from network density and temporal depth, not from any single measurement however precise. Model simulations that assimilate the new data will help clarify whether the observation fits comfortably within known natural variability or represents a shift that existing models do not reproduce.

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