New research on fossilized jaws suggests massive octopuses may have been intelligent top predators 100 million years ago.

The octopus most often found in North Carolina’s offshore waters is the common octopus (Octopus vulgaris). This relatively small species weighs only a few pounds and has a short life span of 12 to 18 months. Currently, only small quantities of octopus are landed in North Carolina commercial fisheries — 79 pounds in 2024 — most of which is bycatch.

Much larger octopus species are found in colder northern waters. Alaska, for example, is home to the giant Pacific octopus (Enteroctopus dofleini), the largest living octopus species in the world. These can reach weights of up to 110 pounds with arm lengths up to 16 feet. 

Even this impressive species, however, is tiny compared to the ancient octopus species that researchers from Hokkaido University recently studied.

Research Need

Fossils show that the first finned octopuses from the Late Cretaceous period, about 72–100 million years ago, were enormous. Based on the size of their fossilized jaws, scientists estimate these octopuses may have reached 20 to 60 feet long (lengthier than a school bus). 

At the time, the oceans were dominated by large predators, such as early sharks and mosasaurs, giant marine reptiles over 50 feet long. However, scientists didn’t know where these giant octopuses fit in the food chain, so they set out to investigate what they might have been eating.

What did they study?

Because fossils rarely preserve stomach contents, and the shape of an octopus’s jaws or arms does not clearly reveal its diet, scientists looked for another clue: wear on the jaws themselves. They studied 27 fossilized jaws found on Vancouver Island in Canada and in Japan. They used a digital fossil‑mining method to examine images of the fossils and detect tiny patterns of wear due to feeding.

What did they find?

Octopus jaws are made of stiffened chitin, rather than bone. When these ancient octopuses bit into prey with shells or skeletons, the predators’ jaws would chip, crack, scratch, and become polished over time. 

The fossils in this study showed a lot of this kind of heavy wear, suggesting that these octopuses used powerful bites and likely hunted hard‑bodied prey. This evidence suggests these ancient octopuses were strong and active predators.

What else did they find?

The researcher team also noticed that the jaws showed more wear on right side than the left. This suggests the octopuses may have preferred using one side of their jaws over the other. This kind of handedness, called “lateralization,” often comes with more complex brains and higher cognitive abilities. 

In short, these ancient octopuses may have been intelligent hunters — similar in that regard to modern octopuses.

So What?

For octopuses to become top predators, they had to evolve powerful jaws while losing the protective outer skeletons that many other invertebrates possess. This gave them flexible bodies and strong bites (unlike many invertebrates, which are often prey), allowing them to compete with some of the largest vertebrate predators in the ocean.

Top predators play an important role in shaping ecosystems and maintaining biodiversity. Understanding their role in the marine food web helps scientists better appreciate how ancient oceans worked.

Reading

Ikegami, S., Mutterlose, J., Sugiura, K., Takeda, Y., Derin, M. O., Kubota, A., Tainaka, K., Harada, T., Nishida, H., & Iba, Y. (2026). Earliest octopuses were giant top predators in Cretaceous oceans. Science, 392(6796), 406–410. https://doi.org/10.1126/science.aea6285

Funding was provided by the following: Japan Society for the Promotion of Science grant 22J13936 (to S.I.); Japan Society for the Promotion of Science grant 23K17274 (to Y.T.); Japan Society for the Promotion of Science grant 19H02010 (to Y.I.); Japan Society for the Promotion of Science grant 22H02937 (to K.T.); Japan Society for the Promotion of Science grant 23H02544 (to A.K., H.N., and Y.I.); Japan Society for the Promotion of Science grant 25K22459 (to Y.T., K.T., and Y.I.); Japan Society for the Promotion of Science grant 26K00821 (to Y.I.); Japan Aerospace Exploration Agency grant JX-PSPC-­540452 (to T.H. and Y.I.); The Canon Foundation 2019 (to Y.I.)

The text from Hook, Line & Science is available to reprint and republish at no cost, but only in its entirety and with this attribution: Hook, Line & Science, courtesy of Scott Baker and Sara Mirabilio, North Carolina Sea Grant.