Octopi have been captured on camera throwing silt and shells at one another, according to new research. Large numbers of Octopus tetricus, also known as the common Sydney or the gloomy octopus gather in Jervis Bay, Australia which is known as Octopolis due to the bountiful hunting conditions that attract the usually lone, anti-social creatures.
After analysing more than 24 hours of underwater video footage taken at the sites in 2015 and 2016, researchers from the University of Sydney were stunned to see the cephalopods throwing algae, silt and shells through the water at other octopi. Two females were the biggest chuckers, making 66 percent of the throws, which tracks with past research that found female octopi throw objects at males when they’re feeling harassed. Individuals of both sexes with darker-coloured skin throw with more force and were more likely to hit another octopus.
The most common object the octopi tossed were shells, which they often chucked while cleaning their dens or after eating. They also threw silt and other debris. The scientists say this is the first time they have documented the behaviour in octopi. The octopi’s motivation for throwing remain a mystery. Lead scientist Professor Peter Godfrey-Smith speculates that the behaviour arises out of a desire for their personal space.