The urge to throw something at someone who’s bothering you is not a behavior unique to people. According to the New York Times and a study published on November 9th, this behavior is also present among octopuses.
While most octopuses live alone, one species, Octopus tetricus, known as the gloomy octopus, are often found together. These creatures live in Jervis Bay, Australia, and are found at gathering sites with abundant food and prime denning conditions; named Octopolis and Octlantis. Since so many octopuses flock to these sites, it is common for them to grab, poke and throw projectiles at one another when they are frustrated.
More than 21 hours of video taken near an octopus den was studied by a group of researchers. Peter Godfrey-Smith, a philosopher of science at the University of Sydney in Australia is one of the leading researchers and authors of the new study. He noted that their throwing behavior was “not at all routine.”
What the octopuses are doing isn’t quite “throwing,” like a human would. In more instances the octopuses were flinging and expelling sand, silt and shells from underneath their bodies. The octopuses gather these materials from the seafloor and hold them until they’re ready to fire. Once ready to fire, the octopus aims its siphon—the organ they use to swim—and pushes water, and the seafloor items collected, out of their body.
Octopuses propel water to swim, and sometimes in captivity have squirted water at people. They are “very intelligent animals,” said Janet Mann. Mann is a biologist at Georgetown University, and said “[octopuses] use water as a tool.”
While it is crystal clear from photos and videos that octopuses do throw things at one another, it is quite hard to prove if this is intentional. The research team tested this by comparing throws that hit other octopuses from throws that didn’t.
Dr. Godfrey-Smith and the other researchers observed many differences while reviewing the footage. Usually, projectiles or debris hitting another octopus were often thrown from the side. When it appeared like an octopus was trying to hit another, they often used silt as their weapon. Scallop shells were usually thrown like “garbage being discarded after eating.”
The biggest insight came from observing one octopus who made multiple attacks. The victim began defending itself after the second throw, though it never threw anything back. “They had dens right next to each other and I think they didn’t like to be in each other’s faces as much as they were,” said Dr. Godfrey-Smith.
Until now, only a few animals were known to throw things, let alone at members of their own species. Now, gloomy octopuses have been added to the list.
“We know so little about the capabilities of marine animals,” said Dr. Mann. “These discoveries are important because they make people think about what’s going on just beneath the surface of the water.”
