Take that! Octopuses caught on camera vigorously throwing debris at each other

Octopuses in Australia have been caught on camera gathering silt, shells, or algae and throwing the debris, according to a new paper published in the journal PLoS ONE. It's the first time this kind of throwing behavior has been reported in octopuses, and the authors believe there is evidence that some of the recorded throws that hit others were deliberately targeted, suggesting the behavior plays a social role.

There aren't that many animals who engage in throwing behavior—defined by the authors as "the ballistic motion of a manipulatable object or material, where 'ballistic' describes free motion with momentum." And throwing behavior that involves aiming at a target is even rarer, although it has been observed in chimps, capuchins, elephants, mongooses, and birds. Spiders sometimes flick or swing silk threads at perceived threats or prey, while archerfish will squirt water at their prey. Dolphins are known to thrash and toss their prey above the water, and they can also toss objects as a form of play.

The authors consider the latter kind of throwing behavior to be a form of tool use, particularly when it involves another member of the same species, with potential purposes being a means of communication, social bonding, or aggressiveness. One might not expect to see this type of throwing behavior among octopuses, which tend to be anti-social: They hunt on their own, and an unexpected encounter with a fellow octopus can lead to an outright fight. Some octopuses have even been known to cannibalize each other.