SYDNEY, Australia — Did a group of octopuses just have an underwater street fight? Researchers in Australia have caught the creatures on camera throwing debris at each other during interactions in the ocean.
The deep-sea creatures were filmed for the first time throwing silt and shells at each other and around themselves. Scientists made the discovery when they recorded the behavior of gloomy octopuses (Octopus tetricus) off the coast of Jervis Bay in New South Wales, Australia.
The animals were recorded using underwater video cameras in 2015 and 2016. Researchers analyzed 24 hours of footage across several days and found 102 instances of debris throwing in a group of around 10 octopuses.
The creatures gathered materials such as silt or shells and released it while using a jet of water from their siphon, a tube-shaped structure that can eject water quickly, to propel it through their arms and through the water. They were able to fling this material several body lengths away from themselves.
To perform the throws, octopuses had to move their siphon into an unusual position, suggesting the behavior was intentional. Both sexes took part in the trash throwing, but females actually completed two-thirds of the throws.
Around half of the throws occurred during or around the time the creatures interacted with other octopus, during activities such as arm probes or mating attempts. About 17 percent of the throws hit another octopus.
Octopuses can change their skin coloration, with dark colors generally representing aggression, and the researchers found that dark-colored octopuses tended to throw more forcefully and were more likely to hit another octopus. In response, octopuses hit by this material often changed their behavior by ducking or raising their arms in the direction of the thrower.
The researchers say that although it is difficult to determine the intent of octopuses propelling debris through the water, it appears that at least in some social contexts, the creatures are capable of targeting throws at fellow octopuses. This type of behavior has only been observed previously in a few non-human animals.
“Wild octopuses project various kinds of material through the water in jet-propelled ‘throws,’ and these throws sometimes hit other octopuses. There is some evidence that some of these throws that hit others are targeted, and play a social role,” the researchers write in a media release.
The findings are published in the journal PLoS ONE.
South West News Service writer Gwyn Wright contributed to this report.