In the club of socialized animals octopuses the entrance is ordered: they are known as avid loners. That’s why the find off the east coast of Australia has surprised marine biologists so much. The international team of scientists discovered a whole octopus city – a settlement of as many as 15 cephalopods of the species Octopus tetricus . They are also called gloomy or gloomy octopuses.
Observation showed that animals are constantly in contact: communication occurs both indirectly and directly. If we consider that octopuses rarely interact with each other (with the exception of mating and conflicts ), this finding can be called unique.
Even more interesting is that there are actually two such dormitory “hostels”: the second one was found in 2009 in the same area. According to scientists, it is possible that some octopuses are not such a loner, as was generally assumed earlier.
In fact, little is known about the secluded life of these animals to scientists. Past work has helped to find out that octopuses, for example, are able to see the light of the skin , and also maintain amazing coordination . Now biologists hope that the study of the octopus city (which, by the way, was nicknamed Octlantis) will help to learn more about the life of these secretive beings.
According to scientists, at first they noticed several protrusions on a flat seabed. On closer inspection, they turned out to be rocks, to which octopuses dragged shells and other remains, apparently, eaten by them creatures (mollusks, sea scallops). Of these, animals built something like a pile to create a shelter for themselves.
Curiously, the first octopus town (Octopolis), found eight years ago, was built around a flat object about 30 centimeters long. It was an object clearly made by man. Then the researchers decided that, probably, octopuses need some kind of “foundation”, on which it is convenient for them to build a settlement.
However, Oxtlantis, located a few hundred meters from the first city, in its architecture is markedly different. It stretches in length by 18 meters, and its width is 4 meters. In this area, there are 13 residential and 10 non-residential “premises” – this is either a lair of shells, shells and stones, or sand holes.
In four points of this “hostel” experts placed cameras, and each recorded ten hours of life octopuses. In the frame got from 10 to 15 animals, which demonstrated different types of social interaction. Among them – mating, aggression, pursuit.
Moreover, biologists noticed signs of behavior characteristic of vertebrates. For example, octopuses were grouped together to drive away uninvited guests. In addition, the marine population did not bypass the “housing issue”: some individuals were not averse to evict comrades from more comfortable dwellings.
“This behavior is the result of natural selection, it is surprisingly similar to the social behavior of vertebrates, which means that under certain conditions the evolution progresses for different groups of organisms,” concludes the leading author of the work, Professor David Scheel of the University of Alaska Pacific .
What is the reason for such an association for living together is not yet clear, especially if we consider that such clusters can attract larger predators. Scientists suggest that the place chosen for octopus cities is replete with food. Or they could be “driven” together by unfavorable conditions in other regions.
Marine biologists plan to continue observations to understand how much different octopus-singles differ from their more socialized brethren. Perhaps, in addition to Oxtlantis and Oktopolis, there are other underwater cities of these animals.
Details of the study are described in an article published in the specialized publication Marine and Freshwater Behavior and Physiology.