“Animals can literally take a picture of their own skin from the inside,” said one of the researchers involved in the study.
The ‘Lachnolaimus maximus’, better known as dogfish, is native to the western Atlantic and has the ability to change color in seconds to camouflage itself and protect itself from predators. This characteristic was noticed a few years ago by the biologist Lori Schweikert during a fishing trip in the Florida Keys, in the USA.
Thus, when the researcher caught this reef fish and threw it into the boat, she noticed something strange: its skin had acquired the same color and pattern as the deck of the ship despite being dead, details a statement from Duke University (Carolina from North).
Interested in this phenomenon, Schweikert decided to investigate the physiology of ‘skin vision’ until publishing in 2018, together with the biologist Sönke Johnsen, a study showing that ‘Lachnolaimus maximus’ carries a gene for a light-sensitive protein. called opsin that is activated in your skin and that is different from the opsin genes found in your eyes.
Recently, in a paper published in the journal Nature Communications, Schweikert, Johnsen, and their colleagues noted that to study mimicry in this species, they took pieces of skin from different parts of the fish’s body and analyzed them under a microscope.
In this way, they noticed that the skin of a dogfish looks like a pointillist painting. Each color dot is a cell called a chromatophore that contains pigment granules that can be red, yellow, or black.
The scientists found that the opsin is not located on the chromatophores as expected, but directly below them. Therefore, the light that penetrates the skin, before reaching the photosensitive layer, must pass through the chromatophores full of pigments.
In addition, the experts indicated that the opsin molecules in the skin of the dogfish are more sensitive to blue light, whose wavelength is better absorbed by the pigment granules of the chromatophores.
The finding suggests that the fish’s light-sensitive opsins act somewhat like an internal Polaroid film, capturing changes in light that is able to filter through the pigment-filled cells above as the pigment granules they are grouped or fanned out.
“Animals can literally take a picture of their own skin from the inside,” Johnsen said.
“To be clear, we’re not arguing that dogfish skin functions like an eye,” Schweikert said, adding that eyes do more than just detect light: they form images. “We don’t have any evidence to suggest that’s what’s happening on your skin,” he added.
The researchers say their study could pave the way for new sensory feedback techniques for devices like robotic limbs and self-driving cars that must adjust their performance without relying solely on eyesight or cameras.