As if the ability to punch through glass weren’t impressive enough, mantis shrimp also have incredibly complex, multifaceted eyes that give them ultraviolet vision, a new study has discovered. While humans have three-color receptors in our eyes, mantis shrimp have up to 12 of these receptors, allowing them to detect colors that fall within the UV spectrum.
“Completely Outside the Visual Range of Humans”
Researchers from the University of Maryland-Baltimore County found that at least six of the mantis shrimp’s photoreceptors use “biological sunscreens” to filter light and provide their unique range of vision. These filters contain MAAs (mycosporine-like amino acids) that many other marine organisms have in their skin.
“The effect is akin to putting [on] red-tinted glasses […] that block other wavelengths of light, except this is being done at the photoreceptor cellular level in shrimp,” researcher Michael Bok said in a new release.
“The mantis shrimp visual system contains six types of photoreceptors functioning completely outside the visual range of humans,” Bok said. “Surprisingly, they produce their six UV photoreceptors using only two types of visual pigments by pairing one […] pigment with one of four UV filters. The UV filters block certain wavelengths of light from reaching the photoreceptors, chromatically shifting their sensitivity.”
Purpose Still Unclear
The researchers are still unsure why the shrimp have such advanced vision. One possibility is hunting down prey: because they live in vibrant reef environments, UV vision could be necessary to differentiate their prey from their surroundings.
Another possibility: Picking up UV light in this way helps the shrimp pick up on social cues from others of their species. Without a big brain to process or think about visual information, seeing in the UV spectrum may help mantis shrimp communicate with each other.
The full findings of the UMBC team can be found in the journal Current Biology.