Octopuses have the ability to turn their colour into black whenever they are intimidated by their neighbors. They not only turn black, but also stand tall and loom over their rivals threateningly, giving them the image of an eight-armed Dracula.

The finding, published as part of a study in the journal Current Biology, shows that some of the octopuses have a social life. It also busts the existing belief in the scientific community that the invertebrates are loners.

The study focuses on a species called octopus tetricus or the gloomy octopus, which was found in the shallows of Jervis Bay, Australia. Probably, the octopuses had gathered at the site to munch on tasty scallops.

Matthew Lawrence, a local diver, was the first to notice that there was a lot of octopus activity going on at Jervis Bay. His findings were noticed keenly by David Scheel of Alaska Pacific University, a marine biologist, and Peter Godfrey-Smith, a philosopher who had been thinking about octopus consciousness.

Scheel, whose team recorded 52 hours of underwater video showing 186 octopus interactions, said there could be more than 10 octopuses at the site, which swarm the area mostly during the Australian summer.

“I took a look fairly early on at one sequence in which one octopus approaches another in a fairly menacing way. He gets all dark, stands up very tall, and the other octopus crouches down and turns very pale. And then, when the approaching octopus persists, the other one flees”, recalls Scheel.

He says that this is immediately followed by the first octopus approaching a third octopus that's nearby. And the third octopus turns dark and doesn't crouch down. “He just stays where he is, holds his ground. It looked like they were signaling to each other”, the marine biologist adds.