Octopuses found in the subtropical waters off northern New Zealand and Australia were thought to be loners. Turns out, they have a small city of their own and are not really loners.

The members of the octopus species Octopus tetricus ‘hang-out’ in their tiny city called ‘Octlantis’. The marine biologists discovered that the octopus city contains dens that were made up of piles of sand and shells, serving as a home to 15 cephalopods (a class of Octopuses).

According to Futurism, the co-author of the study Stephanie Chancellor explained, “In addition to the rock outcroppings, octopuses who had been inhabiting the area had built up piles of shells left over from creatures they ate, most notably clams and scallops. These shell piles, or middens, were further sculpted to create dens, making these octopuses true environmental engineers.”

The city was found off Eastern Australia in an area named as Jervis Bay. However, it’s not the first time researchers have discovered an octopus city. Earlier in 2009 the city of ‘Octopolis’ was also discovered not far away from Jervis Bay.

Generally, octopuses only meet in order to mate but, in Octlantis, the biologists observed the octopuses meeting up, living together and communicating with each other. The creatures even chase unwelcoming octopuses away and also expel each other from dens, informed Science Alert.

“We recorded frequent interactions, signaling, mating, mate defense, eviction of octopuses from dens, and attempts to exclude individuals from the site,” the researchers wrote in their study published in Marine and Freshwater Behavior and Physiology.

Though there is a great quantity of food in the city, it also attracts predators and Octlantis seems to be a harsh place to live in, believed the biologists.

The lead researcher David Scheel said, “These behaviors are the product of natural selection, and may be remarkably similar to vertebrate complex social behavior. This suggests that when the right conditions occur, evolution may produce very similar outcomes in diverse groups of organisms.”

Chancellor concluded, “We still don't really know much about octopus behavior. More research will be needed to determine what these actions might mean.”