Why do scientists think these 65-foot octopuses were the real rulers of ancient oceans before sharks took over?

130675818Octopuses are clever creatures, capable of hiding themselves by changing colours, fitting into any space and being very careful not to put themselves at risk. But the ancestors of modern octopuses lived in a completely different way than previously thought. According to various studies, some ancient octopus species did not hide from predators. Intriguing, right?Those species represented huge hunters that dominated the waters hundreds of millions of years ago. This assumption is likely to rewrite many beliefs about prehistoric marine life.Why are fossilised remains of octopuses hard to findFirstly, one should note that it was quite challenging to make such a discovery, as octopuses tend to leave almost no trace when dead. Due to a lack of bones, shells, and other rigid parts, their bodies decay pretty fast.To overcome this challenge, an international team of researchers turned to studying fossilised jaws of the animals, which happen to be one of the most preserved parts of ancient octopus relatives.Using high-resolution imaging along with artificial intelligence analysis, scientists analysed rock samples found in Japan and Vancouver Island. These fossils originated from the Late Cretaceous period, about 100-72 million years ago.Fossil jaws and their significanceThe fossils of the jaws of these creatures showed some significant details about their behaviour. Scratches, cracks, and polishing on the structure indicated signs of constant and intense biting.Key contributor of the research article titled Earliest octopuses were giant top predators in Cretaceous oceans, published in the journal Science, Yasuhiro Iba of Hokkaido University, revealed that they have determined that the early octopuses were enormous predators who reigned at the pinnacle of the ocean’s food chain during the Cretaceous Period.Considering the size of the jaws, researchers think that the animals were as long as 20 meters, which is about 65 feet. Such animals would be on par with, or maybe even larger than, some other marine reptiles of that time. Jaws were built for hunting, not hidingThe research findings provided insight into the state of the jaws, indicating that the animals were hunting. They didn’t have a diet of softer prey. Instead, they were probably preying upon harder and more difficult animals.The researcher explained that the biggest surprise was the amount of wear on the jaws. In some cases, up to 10 percent of the jaws had been worn down.This is much more pronounced than in many modern octopuses that eat animals encased in a shell. It reveals a more aggressive feeding behaviour and indicates that their diet might consist of tougher marine creatures.Change in the perspective of prehistoric oceansIt has long been assumed that the main predators in prehistoric times were vertebrates like fish and reptiles, with invertebrates playing lesser roles in the food chain. But according to the research, there might have been exceptions in which some invertebrate predators reached the apex of the food chain and competed with other large predators for survival.From the results, Iba concluded that some invertebrates were able to evolve into gigantic apex predators. It should be noted that not all prehistoric octopuses were apex predators, and there is little evidence of it happening among their descendants today.Clues about octopus evolutionMoreover, the research provides clues about how octopuses have evolved throughout history. According to the findings, they existed much earlier than previously thought, and their evolutionary development included acquiring complex behaviour patterns.One intriguing point is that the teeth had signs of unequal wear. This could mean that the species were using one side more frequently when biting. Such behaviour has often been observed in animals with highly-developed brains.These results suggest that early octopuses had the same intelligent traits that are common for their modern relatives.Implications for modern marine creaturesThe image of huge sea creatures terrorising prehistoric ocean waters might be quite shocking. However, such an event is yet another example of new knowledge scientists gain through palaeontology.What is important is that it proves the evolutionary process was not straightforward. Instead, animals that appear insignificant and fragile today could have played entirely different roles thousands of years ago.With the help of modern technologies and fossil specimens, scientists reveal more and more information about the way of life of prehistoric marine creatures.