Monday, November 14, 2022

Members of the species "gloomy octopus" sometimes hurl items at other members of their own species

in Jervis Bay, Australia, unusually large numbers of one species — Octopus tetricus, better known as the gloomy octopus — gather
Though the researchers call the octopuses’ actions “throws,” Jervis Bay is not like a dodge ball court populated by eight-armed players; only in one case did an octopus fling a shell by straightening its arm the way a human would. There isn’t really a word for what the gloomy octopus does, Dr. Godfrey-Smith said. For instance, if an animal feels provoked by its neighbor, it will gather silt from the seafloor underneath its body and hold it there. When ready to fire, the thrower positions its siphon — the tubular organ used to pump water for swimming — underneath its body, which the study authors describe as an unusual stance. Then it will violently expel water to push the debris outward.