This 62-Foot Octopus Was the Ocean's Apex Predator Before Sharks Took Over

Scientists have uncovered evidence that a colossal octopus once roamed the world's oceans during the age of dinosaurs, hunting alongside giant marine reptiles and dominating the food chain in ways that no invertebrate had been known to do. The discovery, published in the journal Science on April 23, 2026, by researchers at Hokkaido University in Japan, has fundamentally changed how scientists understand the early history of octopuses and the role of invertebrates in ancient ecosystems.

The creature, named Nanaimoteuthis haggarti, is estimated to have reached lengths of up to 18.6 meters — nearly 62 feet — making it the largest invertebrate ever described from the fossil record. For context, the modern giant squid, long considered the ocean's largest spineless animal, maxes out at around 12 meters (39 feet). This ancient octopus would have dwarfed it entirely.

Fossil Jaws Unlock a Hidden Chapter of Ocean History

Tracing the evolutionary history of octopuses has long been a challenge for paleontologists because their soft bodies almost never survive long enough to fossilize. What researchers led by Hokkaido University paleontologist Yasuhiro Iba focused on instead were fossilized jaws, one of the few hard structures octopuses possess and therefore far more likely to be preserved in ancient sediment.