Octopuses, squids, and their leggy relatives are well known for their impressive abilities to mimic their environment not just in texture, but also in color. This might not seem too weird until you learn that nearly all cephalopods, the group of animals to which they belong, are thought to only see in black and white. How they manage this camouflage skill has been frequently debated, with suggestions of simple trial and error to being able to see polarized light.
Now a new study, published in the Proceedings of the National Academy of Sciences, proposes a new method that the animals may be using to determine the color of their environment, through an effect known as chromatic aberration. “We believe we have found an elegant mechanism that could allow these cephalopods to determine the color of their surroundings, despite having a single visual pigment in their retina,” said Alexander Stubbs, who co-authored the paper.
Chromatic aberration is an effect familiar to many of us when taking photos, though we may not have known it had a name. It occurs when the lens of a camera fails to focus all wavelengths of light to the same point, often resulting in a fringe of color along the boundaries of objects in the photo. Now two physicist, a father-son team, think that cephalopods may be taking advantage of this effect to determine color in the environment without actually having any of the physiology that we normally associate with seeing it.
Cephalopods are the masters of disguise. littlesam/Shutterstock