Scientists are now well aware of how smart octopuses are, and the more we learn about these intelligent and gentle creatures people once thought of as sea monsters the more we find to respect and admire about them.
They're masterful escape artists, brave warriors willing to battle even the most dangerous predators, and they have been known to use discarded coconut shells as mobile homes.
And if that's not enough to convince you the octopus is an amazing animal maybe their underwater city Octlantis will wow you:
In Jervis Bay, off Eastern Australia, researchers recently spotted 15 gloomy octopuses congregating, communicating, dwelling together, and even evicting each other from dens at a site the scientists named “Octlantis.” The international team of marine biologists, led by professor David Scheel of Alaska Pacific University, filmed these creatures exhibiting complex social behaviors that contradict the received wisdom that these cephalopods are loners. Their study was published in the journal Marine and Freshwater Behavior and Physiology (paywall).
It’s not yet clear what led to the creation of Octlantis or if these sorts of congregations are common.
At least one other gloomy octopus site was found recently, though; it was discovered in 2009, not far away in Jervis Bay, and named Octopolis. At that time it was considered a total anomaly. Researchers believed that the cephalopods gathered there because an unidentifiable human object happened to have formed a central point that the cephalopods surrounded with dens. The unknown artifact was a single object about 30 cm long, heavily encrusted, possibly made of metal. The site has been observed for seven years now, and at any given time, there are somewhere between two and 16 octopuses there.