Off Australia’s east coast in Jervis Bay, there is a real underwater site that seems almost unreal. Beneath the waves, more than a dozen gloomy octopuses have done something no one expected. They’ve built a crowded neighbourhood of shell-studded dens, squabble like neighbours, and even flirt across the sand. Scientists call it Octlantis, and it has forced researchers to rethink how these mysterious creatures live together.
The Unexpected Neighbourhood Beneath the Waves
For decades, octopuses were the ultimate loners of the sea. They preferred solitude, hiding in rocky crevices or abandoned shells, usually venturing out to hunt or mate. In the mid-2010s, researchers watching the seafloor through underwater cameras saw something that made them question it all. At about ten metres below the surface, a cluster of gloomy octopuses (Octopus tetricus) were living side by side in a bustling, shell-filled settlement.
At both sites, the octopuses used piles of discarded shells to build small dens close together, sometimes only a few arm lengths apart. In the sandy spaces between them, the animals could be seen defending homes, chasing rivals, or trying to court nearby partners. It looked more like a busy seaside town than a silent seabed.
From Solitary Hunters to Social Builders
Scientists had already found a similar site in 2009, which they named Octopolis. But Octlantis was different. No man-made objects were attracting the animals, no discarded debris to explain their gathering. This site formed around natural rocks and shell piles built up by the octopuses themselves.
According to researchers, as many as fifteen of the creatures could be seen living in close quarters, using shells and rocks to construct and maintain their dens. In footage reviewed by the research team, the octopuses were seen chasing off intruders, stealing homes, and making daring approaches toward potential mates. One octopus might launch a jet of silt toward a nearby rival, while another could slip into an empty den moments later. It was raw underwater drama, hinting at something much more profound.
The Drama of Octlantis
The daily life of Octlantis plays out like an underwater soap opera. Octopuses have been seen flashing dark colours during aggressive interactions, and individuals of both sexes defend their dens from intruders. Occasionally, one bold individual might crawl right into another’s home, sparking a tangle of arms and clouds of sand. Some octopuses appear to tolerate particular neighbours for a time as they share space or defend nearby dens, then later clash with those same neighbours.
Each den reveals part of this unfolding story. Layers of shells, crab remains, and other debris pile up around entrances, marking long periods of occupation. The seabed around Octlantis glitters with the leftovers of countless meals, forming a bright, shell-covered carpet that reflects the strange social life of its residents.
Rethinking Octopus Intelligence
The discovery of Octlantis suggests that octopuses might be far more complex than once believed. For years, scientists have admired their intelligence: the way they solve puzzles, open jars, and mimic other creatures. But this underwater city shows another side of their minds. Living close together seems to force them to read others’ signals, negotiate space, and cope with social pressure.
Researchers have suggested that these behaviours might involve some form of social learning, where octopuses respond to and possibly learn from each other’s actions. Some argue that this could hint at a local culture at Octlantis, with habits and skills shaped by that particular environment. It’s an extraordinary thought: a culture of cephalopods thriving under the waves.
A Glimpse Into the Unknown
Despite all the observations, Octlantis still raises more questions than answers. Some scientists wonder whether they gain some safety from numbers, or whether competition for limited space simply forces them closer together. Scientists do not yet know the full answer, but they agree that this community challenges the old idea that octopuses always live alone.
In the end, Octlantis is more than just an underwater curiosity. It reminds us that life on Earth keeps surprising us, revealing intelligence and cooperation in the unlikeliest corners of the sea. Somewhere beneath the waves, under the shifting light and soft current, a city of tentacles thrives, suggesting that even animals once thought to be loners can share a world of their own.
