A new study showed that octopuses off the coast of Australia throw objects with the possible intention of hitting each other. The rare behavior has been observed mainly in female octopuses, which are likely to perform throws to get rid of stalking males.
Throws of shells, algae and handfuls of slime were observed for the first time in 2015, in a region of Jervis Bay (in Australia) that earned the nickname “Octopolis” due to the large number of octopuses of the species. octopus tetricus found there.
Throwing behavior was seen as a way of digging burrows, cleaning them or getting rid of food scraps, for example. But occasions when octopuses hit other individuals with the thrown objects left researcher Peter Godfrey-Smith of the University of Sydney and his team in doubt. They didn’t know if the octopuses were intentionally hitting each other or not.
Scientists have done more footage and analysis, and have found that there are differences between the types of shot taken, which suggests that octopuses aim their shots and eventually hit each other on purpose.
To perform the throws, the octopuses hold the objects in their tentacles and then shoot a jet of water from their siphons, performing the launch.
The scientists write that behavior happens in various contexts. There seem to be two main types of throwing: targeted or untargeted. The undirected throw is almost always made between two frontal tentacles and would happen from intentions like those already mentioned: to dig holes and get rid of some objects.
The directed throw – which at least seems to target other individuals – was eventually made from specific launch angles, between tentacles to the left or to the right. These pitches are usually mud and are considerably more vigorous. Researchers believe this type of release can play a social role.
Mainly female octopuses were observed performing targeted throws, throwing objects at other octopuses. In 2016, for example, a female was observed throwing slime ten times on a male who was trying to mate with her. In some of these throws, the male tried to dodge, but five of the throws were successful and hit the animal. “This sequence was one that convinced me [foi intencional]”, affirms Godfrey-Smith.
This type of launch can be used as a form of attack, but researchers haven’t observed any octopuses responding to throws, throwing objects back.
There is another possible explanation for targeted shooting. Researchers have sometimes observed octopuses throwing objects into the void after a few social interactions; this could be a way for animals to vent some kind of frustration.
An octopus has been seen, for example, tossing a shell in a random direction and then changing color after not being matched by a female in a mating attempt.
Some animals are seen throwing objects at other animals or at random. But, second Godfrey-Smith, “It’s especially rare to throw objects at other members of the same population.”