Key Takeaways About Octopus Color Change
- Octopuses change color to camouflage themselves from predators such as stingrays and eels. Octopuses have even been observed to change color while they sleep.
- The octopus' ability to change color is known as metachrosis or physiological color change. In addition to changing color, octopuses can change the pattern of their skin to better blend in with their environment.
- Octopuses can change color in the “blink of an eye,” but the process can be tedious and energy-consuming, according to experts.
At Birch Aquarium in San Diego, visitors can see the gray giant Pacific octopus napping in its habitat. But after a few minutes, they could see a bright red octopus accepting a fish snack from an employee. Does the octopus change color with excitement?
“Giant Pacific octopuses change color throughout the day, and as humans we naturally want to attribute these changes to certain emotions, but rather, there are certain color patterns that correspond to certain behaviors,” says Maddie Tracewell, senior aquarist for animal health at the Birch Aquarium at the Scripps Institution of Oceanography at the University of California, San Diego.
Sleeping octopus often has a white or gray color to match its surroundings.
“When they sleep, they also usually hide in their den and are not very interactive. Usually the greatest color change occurs when they are awake. Octopuses can change colors faster than in the blink of an eye! It's quite spectacular to watch,” says Tracewell.
When an octopus senses danger, it quickly changes color. And while these creatures are masters of camouflage, they are also color blind. Scientists are currently figuring out how octopuses can distinguish colors that they can't even see.
Read more: An octopus' arms can punch, lift and sometimes pull up to 100 times the sea creature's own weight.
Octopuses change color quickly
Physiological color change, also known as metachrosis, is the ability of an animal to quickly and temporarily change its appearance. For octopuses, physiological color change also includes the ability to change its pattern to blend in with a textured background, according to a 2022 study. Vision.
Because octopuses can change colors and patterns in milliseconds, scientists consider octopuses to be champions of camouflage, especially since octopuses cannot even perceive some of the colors that match them.
How do octopuses change color?
In the same Vision study, The researchers wondered how a colorblind animal could camouflage itself so effectively. OctopusesIt is believed that chromatophores (color-producing cells) respond to the brightness of an object, not its hue.
To test how accurately an octopus could match a background color, the researchers worked with a grim octopus (octopus tetracus), A medium-sized octopus native to Australia, named for its sad eyes that give off a wa vibe.
The researchers used a spectroradiometer to determine whether the grim octopuses actually matched the background colors. They found that octopuses can camouflage themselves against backgrounds in terms of brightness and color. But they were not always able to achieve the same level of saturation.
The authors concluded that octopuses likely evolved to be invisible to underwater predators (unlike birds flying above them or people casting nets). Brightness, rather than exact shade matching, is more important when avoiding predators such as sharks or eels.
Why do octopuses change color?
Scientists believe octopuses evolved to change color as a defense against predators. A stingray or eel cannot grab and snack on an octopus that they cannot see. But they also identified other situations in which the octopus changes color.
In a 2021 study in iScience, researchers found that octopuses change color during sleep and are thought to have distinct stages of sleep with more active periods. During the active stage of sleep, octopuses can move on suction cups and change color.
Changing colors is apparently so easy for octopuses that they can do it in their sleep. But it also comes at a high cost, according to a study conducted in PNAS. Octopuses burn a lot of energy when they change color. To compensate for this severe metabolic burn, octopuses have adapted to be nocturnal and rest in dens and other safe places.
And if the camouflage fails, the octopuses can regrow limbs if a predator bites off one of them. When the current giant Pacific octopus first arrived at Birch Aquarium in March 2025, it lost one of its limbs while living in waters near Japan.
“Octopuses have the ability to regenerate their arms, so it was amazing to see this process in action. With each passing month, her tiny 'chubby' arm gets bigger and bigger, and eventually we probably won't be able to tell it apart from her other arms,” Tracewell says.
Read more: Do you dream about octopuses? Their colorful, skin-changing sleep cycles may hold the answer
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