Octopuses in Australia have come up with a useful approach to warding off sexual harassment: they throw shells and sand at aggressors.
Researchers at the University of Sydney have been registering octopuses in Jervis Bay on the south coast of New South Wales since 2015.
Analyzing the images, they found that female octopuses, known as chickens, would deliberately throw shells and sludge at other octopuses, with males often making unwanted mating advances.
In a study posted on the preprint server bioRxiv, the researchers explained how the chickens used their tentacles to put algae, sludge, small shells and other objects under the bodies.
They then placed their siphons, which direct water in to help them swim and steer, to shoot a jet of water at the waste, turning it into projectiles that could land well beyond their range.
“It’s hard to know how best to describe it,” said Peter Godfrey-Smith new scientist.
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A female octopus in New South Wales’s Jervis Bay shoots a jet of water filled with shells, algae, silt and other debris to repel a male interested in mating with her
In a 2015 presentation, Godfrey-Smith said it was not clear whether the behavior was an attack on a rival, accidental or something else.
Octopuses also throw silt and debris to get rid of scraps and dig out their caves.
However, after reviewing more footage, the team concluded that this was intentional behavior other than building a den or eating pitchers.
In one incident, a hen threw sludge ten times at a male from a nearby burrow who attempted to mate with her, nailing him about half the time.
Female octopuses stuff algae, silt, small shells and other objects under the bodies with their tentacles. They then positioned their siphons to shoot a jet of water at the waste, turning it into projectiles that land well beyond their range.
‘That sequence was one that convinced me’ [it was intentional]Godfrey-Smith, author of Other Minds: The Octopus, the Sea, and the Deep Origins of Consciousness, told New Scientist.
However, the male was able to dodge at least some of her attacks.
When aiming for others, octopuses aim their shot between the first and second tentacles on the left or right side. Other casts usually came between the front two tentacles.
That suggested they were aiming for their target, Godfrey-Smith said.
When octopuses aim at others, they aim their shot differently — between the first and second tentacles on the left or right — suggesting they were aiming for a target. The casts for other mollusks were more powerful and contained more silt than shells.
In addition, the casts for other mollusks were more powerful and contained more silt than shells.
In one case, an octopus hit another with a shell by throwing it like a Frisbee with its tentacle.
Interestingly enough, being pelted by silt or shells did not cause a similar reaction in the victim.
Females seemed to be the main aggressors: In total, 15 of the 17 recorded hits were made by chickens, the majority of which were from two specific octopuses, according to the study.
In one instance, after a woman rejected a man’s advances, he threw a grenade in a random direction, Godfrey-Smith said, perhaps to vent his frustration.
Females seemed to be the main aggressors: in total, 15 of the 17 recorded hits were made by chickens, the majority of two specific octopuses, according to the study
Not all victims were unwanted suitors: of the 13 where gender could be determined, five of their victims were male and eight were female.
Breeding is serious business for the octopus: a female can lay up to 100,000 transparent eggs in a fertile period of one to two weeks.
When they hatch, the larvae swim to the surface, although the vast majority are killed by turbulent water or larger sea creatures.
It is rare for animals to throw projectiles, especially at members of their own species.
However, octopuses are also known to use shells to make mobile homes: A 2009 study found that they nested in coconut shells thrown into the sea by humans, in what scientists say was the first “intelligent” use of tools by an invertebrate animal. is.
In addition to projectiles, octopuses have been observed using shells as habitat: Indonesian veined octopuses placed in coconut shells and thrown into the sea by humans, in what scientists say is the first “intelligent” use of tools by an invertebrate.
The more than 20 creatures observed setting up a house did more than just crawl under a handy shell: They collected appropriately sized coconut halves, stacked two on top of each other, and transported them under their bodies for distances of up to 70. foot.
The shells ‘bowls’ were then unloaded and placed together with their open ends to form a den with its own door.
“I could see that the octopus, busy manipulating coconut shells, was up to something, but I never expected it to pick up the stacked shells and run away,” said study co-author Julia Finn, a marine researcher with the Museum Victoria in Melbourne. “It was an extremely comical sight – I’ve never laughed so hard underwater.”