Underwater video cameras have recorded more than 100 instances of dusky octopuses tossing silt and shells at each other in Jervis Bay, Australia.
The video footage – around 24 hours in length – was captured in 2014 and 2015, but it’s only now that the videos have been fully analysed. The team of researchers who studied the behavior published their discoveries today in Plos One.
The Dusky (or Common Sydney) Octopus (octopus tentricus) is native to the waters off the coast of Australia and New Zealand. He has a rusty brown coloring and white eyes. The octopus primarily eats molluscs, but has also been documented eating members of its own species, according to the Australian Museum.
In the videos, the eight-armed cephalopods pick up materials from the seabed like silt and seashells, then push it through the water using their siphon and arms. The octopuses have already been observed pulling sand from their siphon but never throwing more substantial objects like seashells.
The researchers found that the octopuses had to move their siphons into an unusual position – under the web of the octopus’ arms – to eject the material, indicating that they were intentionally throwing the material away.
Teams observed both genders throwing gear; about half of the throws were made while interacting with other octopuses. Only about 17% of pitches actually hit their targets, so if you’re a sports agent reading this, think twice before signing a dark octopus. The eight arms are clearly not as advantageous as they seem.
And if we split the hair (or the gills, or whatever), the octopuses aren’t throwing things at their enemies, Cy Young style. The propulsion is entirely driven by their siphons; the arms simply direct the material.
But look up the definition of “to throw.” Technically, that’s what octopuses do, though it’s a tenuous enough connection that researchers call the action “throwing,” in quotes.
Because some of the throws were made by male octopuses and some by female octopuses, and they happened both in the presence and absence of other octopuses, the researchers aren’t exactly sure. pattern here. At least in some cases, the team believes the throws have a social purpose. And considering that in some of the videos the octopuses are literally covered in slime thrown at them by a nearby octopus, that seems okay.
Octopuses are generally antisocial, the researchers noted in the study, but are sometimes tolerant of other individuals. But what it means to cover another member of your species with silt, algae, and shells may require further investigation.
Throwing behavior places the dusky octopus on a short list of species that have shown some type of throwing behavior, along with chimpanzees, capuchin monkeys, elephants, polar bears, Egyptian vultures and a few others.
Octopuses are very bright creatures. They probably have a good reason for throwing stuff away. We just have to be smart enough to figure out what they’re doing.
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