Octopuses are renowned for their instant color-changing abilities, a skill they use to outwit predators and surprise prey. They have a reputation for being able to instantly change colors, using this skill to confuse predators or surprise their prey. Yet, the energy cost behind this extraordinary camouflage has remained a mystery—until now. The energy costs behind the camouflage have remained mysterious—until recently.
Color change is a vital adaptive mechanism for many animals, though it is thought to require significant energy. Many animals use color change as an adaptation mechanism, but it requires a lot of energy. Now, biologists have measured how much energy octopuses use during their complete color transformations, providing new insights into their biology. Biologists now know how much energy the octopuses consume during complete color changes, giving them new insight into their biology.
While the advantages of an octopus's color-changing abilities are well-documented, their energetic costs have remained largely unknown. The benefits of an Octopus's ability to change color are well documented, but their energy costs remain largely undocumented. This new understanding of the metabolic expense of color change offers insights into the trade-offs octopuses make to remain concealed, explained marine biologist and biology professor at Walla Walla University in Washington, Kirt Onthank.
Like many cephalopods and other animals, Octopuses have specialized skin structures called chromatophores. These tiny sacs of pigment are connected to muscle fibers that function like spokes on a wheel. The tiny pigment sacs are attached to the muscle fibers, which function as spokes in a wheel. When the muscles relax, the pigment sacs shrink to nearly invisible points. The pigment sacs become almost invisible when the muscles are relaxed. When the muscles contract, they expand the sacs, spreading the pigment across the skin and revealing the color. The pigment sacs are expanded when the muscles contract. This spreads the pigment over the entire skin surface.
According to Onthank, each chromatophore acts like a tiny pixel on a screen, with octopuses boasting an impressive 230 chromatophores per square millimeter of skin—far exceeding the 180 pixels per square millimeter on a 4K 13-inch laptop monitor. Onthank claims that each chromatophore is like a pixel. Octopuses have 230 of them per millimeter squared, which far exceeds the 180 pixels on a 13" 4K laptop screen.
To change color, thousands of small muscles within these pixel-like organs contract. These pixel-like cells contract thousands of tiny muscles to change the color. By precisely controlling each chromatophore through their nervous system, octopuses can produce intricate camouflage patterns or elaborate visual displays. Octopuses are able to produce complex visual patterns and camouflage by controlling their chromatophores through the nervous system.
A recent study examined the energy costs of color changes in octopuses. Conducted by Onthank and lead author Sofie Sonner as part of her master's thesis at Walla Walla University in Washington, the research involved analyzing skin samples from 17 ruby octopuses. The research was conducted by Onthank, with Sofie Soner as the lead author for her thesis at Walla Walla University. The study found that fully changing color required an average of 219 micromoles of oxygen per hour—equivalent to the energy the octopus uses for all its other bodily functions while at rest. According to the study, the amount of energy required by the Octopus for its resting body functions is equivalent to 219 micromoles per hour.
Scaling their findings to human proportions, Onthank estimated that if humans had color-changing octopus skin, we would burn an extra 390 calories per day, roughly the same as completing a 23-minute run. Onthank calculated that, if we had octopus-like skin with color-changing properties, it would allow us to burn 390 extra calories each day. This is equivalent to a run of 23 minutes.
Not only cephalopods or octopuses can change color. Sonner also noted that rapid color change has evolved independently across a wide range of species, including amphibians, reptiles, fish, arthropods, and mollusks, highlighting its broad adaptive significance. Sonner noted rapid color changes have evolved in a variety of animals, such as amphibians and reptiles. Cephalopods can change color much more quickly and precisely than animals such as chameleons. These animals use hormones in order to regulate pigment cells. The slower process is likely less energy-consuming.
This study has been published in PNAS.