Female octopuses have catty way of telling aroused males they’re not in mood, study says
Hours of underwater footage show octopuses are well armed, and not just because they have eight of them. They’re known to coordinate their limbs and manipulate water to catapult shells, algae or silt to other octopuses in true circus cannonball style.
Experts say the behavior is mostly performed out of aggression, but it has been difficult to determine if the catty act is intentional or accidental. Now, new evidence collected over eight years suggests some female octopuses are deliberately chucking silt — fine sand or clay made of rock and mineral particles — at aroused males to tell them they’re not in the mood.
Out of 101 throws observed in 2015 off the east coast of Australia — only some of which were targeted at other octopuses — 90 were done by females and 11 by males. In fact, just two females were responsible for about 66% of all observed throws.
In one scenario, researchers witnessed a female throw material at just one persistently aroused male neighbor a total of five times.
And as if in a dodgeball game, targeted males at times try to duck from flying objects or raise their tentacles up in defense — but those observed in the study were successful only about half the time. The research, which has not yet been reviewed by other experts, was posted online Aug. 19 on the preprint server bioRxiv.
Still, males at the mercy of aggravated females didn’t retaliate and throw material back at them; throws also didn’t trigger any fights. Often, males just flinch and sit back, sometimes throwing whatever is nearby into empty water and breathing heavily in a sort of tantrum.
Octopuses launch rocks or shells by holding them under their bodies right over a funnel that sits by their eyes. This funnel, called a siphon, quickly pushes a jet of water out, propelling the object as far as several body lengths. The darker their color and the more powerful their throw, the more aggressive the octopuses are in any given moment.
The study’s data comes from nearly 21 hours of video of wild octopuses from 2011 to 2018.
It’s relatively common to see the mollusks fling objects into the water, such as when spring cleaning their intimate dens or discarding crumbs from dinner, but throws targeted at other octopuses are less researched. Those observed in the study differed from the usual throws researchers might find octopuses performing in the wild.
For example, octopuses that hurl material directly at others tend to eject stuff with their most frontal arms, display dark, uniform body patterns and throw mostly silt. Some octopuses also turn their bodies slightly to get a better shot at their target.
“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,” the researchers said in their study. “Even if no intention to hit other octopuses lies behind these throws, they do have social effects in interactions between individuals at this site.”
Other than angry humans, targeted throws have also been observed among some chimpanzees, elephants, mongooses and birds, according to the researchers.
This story was originally published August 30, 2021 at 6:10 PM with the headline "Female octopuses have catty way of telling aroused males they’re not in mood, study says."
