The Giant Pacific octopus is so clever that it had been fooling human beings, the most intelligent species on earth, for decades by successfully hiding its types. The largest known octopus on earth is now believed to have two distinct species, with physical and behavioural differences.

This type of octopus, found in waters from California and Alaska to Japan, has been long suspected to have variations that have not caught the human eye. Recently, scientists have discovered a new 'frilled giant octopus', which had so longed seamlessly merged with the more common giant Pacific octopus.

In 2012, researchers from Alaska Pacific University and US Geological Survey found two distinct types of octopuses caught in shrimp pods in Prince William Sound. They collected a swab of epithelial tissue from the newly observed ones and carried out its DNA analysis.

Nathan Hollenbeck, then an undergraduate student at Alaska Pacific University, observed these creatures for his senior thesis when they climbed as bycatch into the shrimp traps. "Usually the octopuses have eaten the shrimp. SO there's a lot of shrimp shells and legs and antennae," Hollenbeck told Earther.

Soon, it was evident that there were two kinds of giant octopuses frequenting that area. The other kind had a distinctive frilly structure along its body length and eyelash-like raised skin, along with two white spots on the head, instead of the usual one.

DNA samples from the octopuses' arm tips and swabs proved that the frilled octopus is genetically different from the usual Pacific octopus. This study, published in the American Malacological Bulletin, was conducted by Hollenbeck and David Scheel.

According to Scheel, this cannot be the first time that frilled octopuses came in close proximity with humans. "Presumably, people have been catching these octopuses for years and no one ever noticed," he says.

The newly discovered species has been found only in the stretch between Juneau to the Bering Sea. They generally live in deep waters; however, they have often been spotted in shrimp, crab and cod pots.

Another evidence of the octopus' intelligence lies in the fact that scientists are yet to determine the total number of creatures existing in the world, thereby failing to assign them a conservation classification. It is also tough to make out whether they are being overfished.

However, scientists have urged people to maintain extreme conservative measures for these animals as so little is known about them. As the two species are so different in appearance, it is expected that they might exhibit different habitat selection and ecology.

"I've been thinking: why would an octopus have a ledge coming off its body like that? Maybe we're seeing differences in their habitat selection and ecology reflected by differences in their body," says Scheel.

Although the frilled octopus largely remains a mystery, the study authors are hopeful that further observation may enlighten us more about this highly intelligent marine creature.