Female octopuses throw objects at males who harass them | University of Sydney research

A survey conducted by scientists at the University of Sydney reveals a previously unknown behavior of female octopus. According to observations made in the bed of Jarvis Bay, in an area of ​​the Australian coast known as “Octlantis”, in some cases they resort to the throwing of objects to repel the harassment of the males in. mating quest.

A prepublication published in the bioRxiv database explores the issue in detail. The research was conducted in collaboration with Peter Godfrey-Smith, David Scheel, Stephanie Chancellor, Stefan Linquist and Matthew Lawrence.

Although a number of wild animals have been documented to propel things towards other animals, only a few, like chimpanzees, refer to their own species. “It is particularly rare to throw objects at other members of the same population,” says Godfrey-Smith.

Life at Octlantis

Since 2015, the group of researchers have been filming the behavior of octopus (Octopus tetricus) in a small area of ​​the seabed where the sand is soft enough that they can dig their burrows with ease. As a result, an abnormal number of octopods have concentrated there. This allowed them to collect video evidence of octopuses throwing objects.

Scientists at the University of Sydney then began to identify a pattern: in general, octopuses tend to throw silt, algae or objects like seashells by propelling them with jets of water, either to remove food debris, or to dig during the construction of their burrows.

Females and males

But with the buildup of material, they turned their attention to the females who threw objects like silt (a type of soft sediment) or algae at the males after an unsuccessful mating hunt. In these cases, the selection of the tentacles changed and it was possible to see how they “focused” on their victim in the range before propelling the object.

Of particular significance was a video in which a female threw slime 10 times at a male from a nearby den trying to mate with her. “This streak was one of those that convinced me,” says Godfrey-Smith.

On four of these occasions, the male attempted to “squat”, although he was not always successful. In two cases, he anticipated the movements of the female’s movements and began to dodge before the silt was thrown at him.

The team decided to publish the results as a prepublication after the publication of an article suggesting that polar bears sometimes use rocks or chunks of ice as weapons while hunting, such as throwing rocks from cliffs at them. walruses.