The Gloomy Octopus Hurls Things at its Neighbors

Today is the day you can emotionally identify with an invertebrate. Why?  A study of octopuses by researchers at the University of Sydney in Australia revealed a behavior rarely witnessed in the animal kingdom — the octopuses were chucking things at each other.

The study, amusingly named “In the line of fire: Debris throwing by wild octopuses,” focuses on Octopus tetricus, otherwise known as the gloomy octopus.

gloomy octopus

A gloomy octopus propels debris at another gloomy octopus (indicated by the arrow). Photo: Godfrey-Smith et al.


Scientists viewing 21 hours of video footage taken in 2015 observed the behavior in question. The irritated gloomy octopuses gathered shells, silt, or algae in their arms and web. They then used their siphon (the organ by which cephalopods propel themselves) to shoot the debris forcefully through the water.

While the behavior certainly wasn’t the norm, it happened enough that the scientists came up with a ranking system to judge the type of debris, intensity of throw, and other factors.

a graphic illustrating the gloomy octopus' throwing method

It’s not exactly a fastball but it does the trick. Photos/illustration: Godfrey-Smith et al.


“We were seeing it reasonably often,” Peter Godfrey-Smith, philosopher of science at the University of Syndey and lead author of the study, told The New York Times.

A gloomy ocean neighborhood

Gloomy octopuses, like most octopuses, are normally solitary, anti-social animals. But two locations in Jervis Bay, Australia are apparently octopus heaven, with plentiful food and nice hiding places.

Even better for cephalopod-fancying researchers down under, the locations are surrounded by less food-and-shelter-abundant areas. The upshot? A consortium of gloomy octopuses all jostling for snacks and shelter. And sometimes things get heated.

In most of the footage, it’s a little unclear if the gloomy octopuses actually mean to hit each other with their projectiles, Godrey-Smith told the NYT. But in two cases, one octopus repeatedly “landed hit after hit,” on a neighbor, prompting the abused animal to start ducking in anticipation. If you live in certain neighborhoods, this behavior may seem familiar.

“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,” Godfrey-Smith continued.

Many species in the animal kingdom use projectiles, but only some social mammals — including, you guessed it, human beings — actually throw things at each other.

Andrew Marshall

Andrew Marshall is an award-winning painter, photographer, and freelance writer. Andrew’s essays, illustrations, photographs, and poems can be found scattered across the web and in a variety of extremely low-paying literary journals.
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