Giant Octopuses in Ancient Oceans
Giant octopuses may have dominated the ancient oceans around 100 million years ago, during the era when dinosaurs roamed the land, according to recent research findings.
Some of the earliest octopuses are thought to have been formidable predators, equipped with strong arms for seizing prey and beak-like jaws capable of crushing the shells and bones of other marine animals.
A new study examining remarkably well-preserved fossil jaws suggests these creatures could have reached lengths of up to 19 metres, potentially making them the largest invertebrates ever identified by scientists.
For many decades, palaeontologists believed that the largest predators in the ocean were vertebrates—animals with backbones such as fish and marine reptiles—while invertebrates like octopuses and squid were considered to play more subordinate roles.
New research conducted by scientists from Hokkaido University in Japan challenges this traditional view of ancient octopuses.
Their analysis of fossilized jaws indicates that giant octopuses once glided through prehistoric seas with the capability to chew through the hard shells and skeletons of large fish and marine reptiles.
Size and Feeding Adaptations
The study estimates the body length of these ancient octopuses to have been approximately 1.5 to 4.5 metres. When including their long arms, the total length could have ranged from roughly 7 to 19 metres.
Even at the lower end of this size range, these animals would have been enormous compared to modern octopus species.
Another notable observation is the uneven wear on the fossilized jaws, differing from the left to the right side. This suggests that these animals may have favoured one side when feeding.
In living octopuses, favouring one side of the body over the other is associated with advanced brain function.
Modern octopuses are well known for their intelligence, problem-solving abilities, and complex hunting strategies.
The Giant Pacific Octopus, which is the largest living species today, can have an arm span exceeding 5.5 metres.
Video footage has shown these animals taking on sharks more than a metre in length.
"With their tentacles and their suckers they could perfectly hold on to such an animal and there is no escape," said Christian Klug, a palaeontologist at the University of Zurich, who reviewed the research.
Remaining Questions and Insights
Despite these findings, many questions remain unanswered. Scientists can only speculate about the exact shape of these ancient octopuses, the size of their fins, or their swimming speeds.
No fossils have yet been discovered containing stomach contents that would provide direct evidence of their diet.
Dr Nick Longrich, a palaeontologist at the University of Bath, suggested that his hypothesis is that these giant octopuses primarily preyed on ammonites.
However, similar to modern octopuses, they likely were opportunistic and voracious predators that would not have passed up other prey if the opportunity arose.
"It's going to take a while before we figure this thing out," he said. "It's a bit of a mystery."
For now, the fossil evidence offers an intriguing glimpse of a giant of the deep that may have roamed ancient seas, equipped with a crushing jaw, powerful arms, and a brain that might have helped it compete with other top predators.
The research has been published in the journal Science.
