Having recently been seen punching fish for no reason, octopuses have now been spotted launching debris at one another in an apparent display of irritation. Describing this unusual behavior in an as yet un-peer reviewed study, researchers suggest that the animals’ tendency to aim projectiles at specific individuals highlights their extraordinary intelligence and complex social dynamics.
The petulant outbursts were recorded on camera off the coast of Australia in 2015. Initially, researchers were unsure if the throws were deliberate or accidental, although a more thorough analysis has left the study authors with little doubt, New Scientist reports.
“Wild octopuses at an Australian site frequently propel shells, silt, and algae through the water by releasing these materials from their arms while creating a forceful jet from the siphon held under the arm web,” write the authors.
“These 'throws' occur in several contexts, including interactions with conspecifics, and material thrown in conspecific contexts frequently hits other octopuses.”
On one occasion, the researchers even observed an octopus using its tentacle to fling a shell like a frisbee, resulting in a direct hit on another individual. Ouch.
Overall, females appear to be much more inclined to toss items at others, with the researchers claiming to have only seen 11 throws from males compared to 90 from females. In many cases, these acts of aggression appear to be responses to harassment or irritating behavior from other individuals. For example, one female was observed throwing silt ten times at a male who repeatedly attempted to mate with her.
Octopuses have previously been observed throwing debris while clearing out their dens or discarding food, leading the researchers to question whether these direct hits were merely accidental. However, they soon noticed that the animals changed their behavior when targeting other octopuses, indicating that these projectile attacks were indeed deliberate.
For example, octopuses tend to use their front tentacles to grasp items before expelling them from their dens, yet were seen using side tentacles and changing their body position in order to aim missiles at other individuals. Some octopuses even appeared to anticipate these throws and attempt to duck, suggesting they knew what was coming.
“All this is evidence that throws in some cases are targeted on other octopuses, and function in the management of social interactions, including sexual interactions,” write the authors.
On other occasions, however, octopuses launched items into empty space in an apparent outlet for their frustration. One male was observed throwing a shell in a random direction, changing his color, and accelerating his breathing after having his sexual advances rejected by a female.
Given that very few species have the intelligence to throw objects at other members of their own population in order to communicate feelings of annoyance, this behavior provides yet more evidence for the remarkable cognitive capacity of octopuses.
Summing up, the researchers conclude that “octopuses can thus definitely be added to the short list of animals who regularly throw or propel objects, and provisionally added to the shorter list of those who direct their throws on other animals.”
[H/T: New Scientist]