A new study suggests that the top predator in the oceans 100 million years ago may have been a massive, kraken-like octopus. Analysis of fossilized jaws reveals that these ancient octopuses, with eight arms and bodies exceeding 60 feet (18 meters) in length, once hunted alongside other fearsome marine reptiles.
Discovery of Giant Octopus Jaws
Researchers studied the jaws of 15 ancient octopus fossils previously found in Japan and Canada's Vancouver Island. They also identified 12 more jaws from Japan using a technique called digital fossil mining, which scans rocks in cross-sections to reveal hidden fossils. By comparing these jaws to those of modern octopuses, they estimated the ancient creatures ranged from 23 to 62 feet (7 to 19 meters) in length. The largest jaw was significantly bigger than that of any modern octopus, said co-author and paleontologist Yasuhiro Iba of Hokkaido University.
Evidence of Powerful Predation
The largest jaws showed significant wear and tear, including scratches, chips, and rounded edges, suggesting that the animals repeatedly crushed hard prey such as shells and bones, according to Iba. This indicates that these octopuses were formidable predators, capable of competing with sharks and marine reptiles like mosasaurs and plesiosaurs for food.
Challenges in Studying Soft-Bodied Creatures
Because octopuses have soft bodies that do not preserve well, it has been difficult for scientists to determine their size and ecological role. There has also been a perception that squishy invertebrates were not formidable enough to be top predators. However, octopus beaks are made of stiffened chitin, tough enough to crush shelled and bony prey.
Implications for Ancient Food Webs
Without access to stomach contents, it is hard to know exactly what these ancient octopuses ate or if they truly competed with other top predators. They may have snacked on fish or snails, snatching prey with flexible arms and breaking it apart with their beaks. Paleontologist Neil Landman of the American Museum of Natural History, who was not involved in the research, noted that looking for octopus fossils in other places could help scientists piece together the marine ecosystem through time.
The findings were published Thursday in the journal Science. University of Alabama paleontologist Adiel Klompmaker, who had no role in the study, described these ancient krakens as a fearsome sight to behold.
