When humans are embarrassed we sometimes change color—we redden with embarrassment or become pale with fear. New research suggests octopi do so as well.
According to a report published in this week’s issue of Current Biology, some octopi may become darker to communicate aggression toward one another.
Octopi, squid, and cuttlefish—boneless sea creatures known as cephalopods—have been known to change color in a fraction of a second. Cells that sit underneath the animals’ top layers of skin can display a variety of hues to blend in with the environment, mimic other animals, or indicate that they are poisonous to would-be predators.
Scientists previously assumed that octopi kept to themselves. However, according to Discover, one of the study’s co-authors noticed that several shallow-water octopi appeared to be engaging with one another in a small bay off the coast of Australia. Researchers set up GoPros and collected almost 53 hours of footage of Octopus tetricus (also known as the Gloomy Octopus). They recorded 186 distinct interactions. They observed that as the animals became darker, raised the sack above their eyes, and spread out the area around their beaks, they were likely going to provoke a nearby octopus. If the reacting octopus was lighter in color, it would likely retreat. Researchers still aren’t sure why these animals initiate scuffles.
“We should no longer consider octopuses as solitary or asocial,” the authors write.
You can watch the octopi tussle in a video compiled from footage of the study by the Australian Broadcast Corporation: