Cannibal octopuses change their ways forming 'Octlantis' community off NSW coast

Scientists may have made a key discovery in their research into the behaviour of octopuses after finding an underwater “city” of them living off the coast of New South Wales.

It’s been nicknamed “Oclantis” and lies in Jervis Bay off the NSW east coast, Science Alert reports.

The find means the cephalopods aren’t as gloomy and isolated as once thought.

It’s also not far from “Octopolis”, an area where octopuses were found fighting in 2009.

A report in National Geographic published in 2016 says “most octopuses are loners” “if not cannibals” and only the larger Pacific striped octopus, seen off the coast of Central America, share dens and meals.

But an international team of researchers from Alaska Pacific University have filmed a group of about 15 octopuses meeting up, living together and communicating.

Living in dens made from piles of sand and shells, they were also seen chasing away unwelcome octopuses and evicting each other from dens.

“Oclantis” is made out of piles of sand and shells and it is about 10-15 metres under water, and measures 18x4 metres.

Alaska Pacific University professor David Scheel told digital news outlet Quartz the social behaviour the octopuses were showing was a “a product of natural selection”.

He also compared their behaviour to “vertebrate complex social behaviour” and said it’s possible octopuses must be interacting regularly over generations.

Adding to the mystery, researchers believe the octopuses originally began fighting in “Octopolis” because of a piece of metal found lodged in the seabed.

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However, in “Oclantis” there is no human object or point of reference to explain the colony.

But University of Illinois-Chicago researcher Stephanie Chancellor said it’s possible octopuses were inhabiting the area after a build up of shells from the creatures they had been eating.

“These shell piles, or middens, were further sculpted to create dens, making these octopuses true environmental engineers,” she said.