Australian scientists have caught footage of octopuses throwing things at one another (Credit: Dr. Peter Godfrey-Smith et al.)

Octopuses are among the smartest animals in the ocean. The invertebrates can navigate through mazes, complete tasks in exchange for food, and even recognize human faces. Now, the clever animals have been caught throwing objects at one another. The rare behavior has previously been seen in only a few animals like chimpanzees, elephants, and birds.

Scientists at the University of Sydney discovered the odd conduct while studying the animals in Jervis Bay, Australia. Octopuses are usually solitary creatures. However, Jervis Bay's rich resources attract many gloomy octopuses (Octopus tetricus). Dr. Peter Godfrey-Smith and his team were curious to learn how the mollusks interact with each other. They placed cameras in two areas with large octopus populations to observe their behavior.

Octopus caught in the act of hurling debris at a neighbor (Credit: Dr. Peter Godfrey-Smith et al.)

The over 20 hours of footage captured between 2015 and 2016 show the mollusks tossing silt, algae, and even shells. In some cases, the animals seemed to be cleaning their dens. Other times, however, they appeared to be hitting another octopus. The researchers noticed that these throws were more forceful and were carried out using specific arms. The target octopus often ducked or raised an arm to avoid being hit. Fortunately, the weapon of choice was usually silt.

The team observed that female octopuses were more likely to throw objects than males. The animal's skin color also appeared to play a role. Darker octopuses tossed things more often and forcefully than their paler counterparts. The scientists published their findings in the journal PLOS ONE on November 9, 2022. They do not know the reason for the targeted throws. But they suspect it may be to protect personal space.

"Most throws do not hit others," said Dr. Godfrey-Smith. "Only a minority of cases appear to be targeted. I'd speculate that a lot of the targeted throws are more like an attempt to establish some 'personal space.' But this is a speculation. It's very hard to know what their goals might be."