Giant Kraken-Like Creatures Hunted Ancient Oceans 100 Million Years Ago, Competing with Top Predators

Researchers have identified fossil evidence suggesting that giant, octopus-like creatures were apex predators in Earth’s oceans approximately 100 million years ago during the Late Cretaceous period, challenging previous assumptions about marine food webs of that era.

The findings stem from an analysis of exceptionally preserved jaw fossils discovered in regions that were once submerged seas, including areas now part of Japan and Canada’s Vancouver Island. These fossils belong to a species scientifically named Nanaimoteuthis, which researchers describe as among the earliest known finned octopuses.

According to the study published in the journal Science, the size of these ancient cephalopods was estimated by analyzing the dimensions of their beak-like jaws. Based on this method, Nanaimoteuthis individuals ranged from approximately 7 to 19 meters in length, or about 23 to 62 feet.

The physical structure of these creatures included eight arms and elongated bodies, with some specimens possessing paddle-shaped fins on their heads—a characteristic feature of finned octopuses. These anatomical traits suggest they were active swimmers capable of hunting in open marine environments.

Microscopic examination of the jaw fossils revealed significant wear patterns consistent with repeatedly crushing hard materials such as shells and bones. This evidence supports the conclusion that Nanaimoteuthis fed on prey with durable external structures, positioning it as a top-tier predator in its ecosystem.

Yasuhiro Iba, associate professor of Earth and planetary sciences at Hokkaido University and a coauthor of the study, emphasized the rarity of such discoveries due to the biological makeup of octopuses. “Octopuses rarely fossilize because most of their bodies are soft, with only a few hard parts like the jaws likely to be preserved after they die,” he noted in statements reported by multiple news outlets.

The research team conducted a fresh analysis of 15 large jaw fossils that had previously been collected but not fully examined. By focusing on these durable mouthparts, scientists were able to infer both the size and ecological role of these ancient animals despite the lack of complete body specimens.

Iba added that the discovery was unexpected given the limited fossil record of cephalopods from this time period. “We were surprised. Finding animals this large and ecologically important in the Cretaceous ocean was beyond our expectations,” he said, underscoring how the find reshapes understanding of marine biodiversity during the age of dinosaurs.

During the Late Cretaceous, oceans were inhabited by formidable marine reptiles such as mosasaurs and plesiosaurs, as well as large sharks. The identification of Nanaimoteuthis as a potential apex predator suggests that cephalopods played a more significant role in these ecosystems than previously recognized.

Scientists note that the preservation of soft-bodied organisms like octopuses is exceptionally uncommon in the fossil record, which has historically led to an underrepresentation of their evolutionary history and ecological impact. This discovery highlights the importance of focusing on durable anatomical features—such as beaks and jaws—when studying extinct invertebrates.

While the study provides strong evidence for the size and predatory behavior of Nanaimoteuthis, researchers acknowledge that many aspects of its biology, including lifespan, reproductive habits, and exact diet composition, remain uncertain due to the absence of complete fossils.

The peer-reviewed research was published in Science on April 23, 2026, and has since been reported by major science and news outlets including CNN, the Associated Press, and National Public Radio. Continued exploration of fossil sites with suitable geological conditions may yield further insights into the diversity and ecology of prehistoric cephalopods.