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Giant octopus was a top predator at the time of the dinosaurs

The picture shows a large marble-pink octopus floating in a dark blue sea. It has large tentacles and is peering out of one yellow eye.Image source, Yohei Utsuki, Department of Earth and Planetary Sciences, Hokkaido University
Image caption,

This is what artists think the extinct giant octopus might have looked like

New research suggests that 100 million years ago giant octopuses could have be found in the oceans - likely around at the same time dinosaurs roamed the earth.

Scientists have been studying fossilised jaw like structures, called beaks, of the octopus species called Nanaimoteuthis haggarti.

The results suggest that they could also have been powerful predators.

Researchers say that there is evidence of wear that came from eating animals that had hard shells and skeletons.

The size of the fossils means they could have been up to 19 metres in length.

However, many questions remain. Scientists can only guess at the exact shape of the animals, the size of the fins, or how quickly they could swim.

Until now, it was believed that the largest ocean predators were vertebrates with backbones like fish and reptiles.

But this new discovery could potentially make this octopus the largest invertebrate ever known.

Close-up of a giant Pacific octopus with its tentacles spread. Image source, Getty Images
Image caption,

The Giant Pacific Octopus is the largest living species today

The study estimates a body length of about 1.5 to 4.5 metres, and when their long arms are included, comes to a total of about 7 to 19 metres.

Even at the lower end of that range, the animal would have been enormous by today's standards.

The largest living species today is the Giant Pacific Octopus, which has a possible arm span of more than 5.5 metres.

The research published in the journal, Science, was carried out by a team from Hokkaido University in Japan.