Octopuses belong to the most fascinating creatures on the planet, wouldn’t you agree? They look decidedly alien with their huge heads and eight arms or legs. Their skin can change color and texture, so that they can mimic seaweed at one moment and strange rock formations at the next. They have three hearts, nine brains, no bones, and blue blood. And their intelligence is extraordinary – they’re known to solve problems, are amazing escape artists, and use tools. The YouTube video below shows a Veined Octopus carrying two halves of a coconut shell and then pulling them together to hide inside.
Or watch this BBC-video which shows how a giant Pacific octopus steals crabs out of a fisherman’s trap.
Their large, highly developed brains follow an evolutionary track that is entirely different from that of human brains: our most recent common ancestor is more than twice as ancient as the first dinosaurs. Cephalopods (the class of marine mollusks which includes octopuses, cuttlefish, squid, and nautili) are about as close to an intelligent alien creature as one can find on earth. For other examples of convergent evolution, the independent development of similar features in species over different periods or epochs in time, take a look at the University of Cambridge’s Map of Life website – it’s quite fascinating.
The literature I’ve read about octopuses always stressed the fact that they are hermits, happy to be alone and be left alone. I sympathize; in general, I prefer to be by myself or with just a few close friends. But discoveries a few years ago shed a new light on the social life of these creatures.
In Jervis Bay on the south coast of New South Wales in Australia, marine biologists discovered first one and then another settlement where about 15 Gloomy Octopuses (Octopus tetricus, or common Sydney octopus, so called because its color is normally grey. Talk about anthropomorphism.) all reside quite close to each other. The first site, called Octopolis, was found in 2009 by Matt Lawrence, an Australian scuba diver who posted about his discovery on TONMO – The Octopus News Magazine Online – a community-oriented resource site for anything that relates to cephalopods. In a forum thread called “Octopus living in groups and more stuff” Matt describes his experiences under water and posts lots of pictures. I heartily encourage you to take a look and read some of the fascinating entries which cover over seven years.
He noticed lots and lots of empty shells at the bottom of the sea, at a depth of about 15 meters. At least eight octopuses lived there in close proximity; they had built their dens there by burrowing holes through the pile of shells, which made the walls of their dens more stable than the fine sand of the ocean floor. They seemed to be quite clever engineers, incorporating empty glass bottles and other human-made trash floating around.
Matt frequently returned to the site so he could observe the animals who got quite used to him. Soon he witnessed some strange behavior: they were fighting, obviously about territory. One big, possibly dominant, animal would get all puffed up, swim to another octopus’s hole and cover it up, thus forcing its inhabitant to come out. There’d be a quick fight, and then the larger one would chase the other one off and evict him!
The photo above is a visual puzzle: apparently, there are at least five octopuses in the picture. If you follow the link in the caption you’ll learn where to find them.
Matt’s discovery alerted scientists fascinated by octopuses: Peter Godfrey-Smith (who coined the term Octopolis), for example, a professor of philosophy at CUNY, New York, and a professor of the history and philosophy of science at the University of Sydney. Together with David Scheel, professor of Marine Biology at Alaska Pacific University in Anchorage, and others, Peter joined the divers in order to study this fascinating site. Then, in 2016, two other divers – Marty Hing and Kylie Brown – discovered another area at Jervis Bay, not far from Octopolis, where more than ten octopuses built their dens quite close together. They called it Octlantis.
The behavior of Octlantis inhabitants was similar to those who lived at Octopolis: they interacted more with each other and were more active than is usually observed with octopuses. They display what Peter Godfrey-Smith terms “coordinated, whole-body behavior”:
The animals shift between different kinds of motion. In jet propulsion, the arms are brought together and the animal becomes a slender missile. When crawling, the arms go everywhere at once. Some behaviors are packaged together into what appear to be social displays. An aggressive animal will often stand very tall with arms spread, and with the mantle (the large rear part of the body) pointing straight upward. This is combined with intense dark colors—an octopus can change its entire color in less than a second. It makes the animal look as large as possible, and genuinely ominous. We call this the Nosferatu display.1
They also throw things at each other! Sometimes this could have been by accident; when an octopus cleans out their den, they throw out all the debris that had accumulated, and it can accidentally hit another animal close by. At other times it looks more deliberate, when a female is bothered by the advances of a male, for example. The scientists are quite cautious with interpreting octopus behavior and intentions because these creatures are so alien.
Except for the time when Covid put a hold on all social interactions, the divers and scientists who researched the two sites at Jervis Bay returned quite regularly. The last update I could find is from September 9, 2023. There were only two or possibly three octopuses at the Octopolis site, but the numbers had been going up and down before; maybe the population will be denser again in the future. Octlantis had at least five dens, maybe six; lower than the 13 that were recorded in 2016, but they may be going up again. And I’m looking forward to future discoveries of similar sites!
i love how the scuba diver guy pointed about their combative behavior like that's what made it newsworthy / if they live together in communities they must spend alot more time getting along even cooperating / that would be alot more interesting