Octopuses Change Colors to Intimidate Their Foes, Study Finds

Octopuses are well-known for being anti-social, but new research is proving they aren’t as reclusive as scientists previously believed. In fact, their knack for changing their appearance—long thought of as an effective way to hide—may also be a way they communicate with other octopuses, a new study finds. Research from Alaska Pacific University and the University of Sydney published in Current Biology indicates that the ability to change the hue of their bodies plays an important role in conflicts between octopuses.

The researchers studied a species called Octopus tetricus by setting up cameras in the shallow waters of Jervis Bay off the eastern coast of Australia. In more than 50 hours of video, they catalogued 186 octopus interactions, noticing a pattern in the social lives of the eight-tentacled creatures: They tend to turn dark colors when they feel aggressive.

The octopus in the background of the photo is adopting an aggressive posture, while the pale octopus in the foreground is being submissive.

When a dark-colored octopus approached another dark-colored octopus, the two were more likely to fight, whereas if a light-colored octopus met a dark octopus, the paler of the two was likely to scuttle off in retreat. Dark octopuses were more likely to stand their ground during a beef, while lighter octopuses were more likely to beat it.

In addition to dimming the color of their bodies, aggressive octopuses typically stand up tall and spread their web out in a position "nicknamed the Nosferatu pose,” making themselves look as large and forbidding as possible, while submissive octopuses will slink down.

This adds to previous research that found that octopuses can be social in captivity, even cohabitating in dens. The authors of the current study suggest that octopuses may behave more socially in areas where there’s a lot of food to be had, but limited places to hide. The growing body of evidence for octopus interactions (that don’t involve eating each other) “indicates that we should no longer consider octopuses as solitary and asocial,” they write.

[h/t: NPR]

All images by David Scheel