Mantis shrimp are famous for their deadly punch, but it seems their vision is equally eye-popping. Undoubtedly one of the most interesting crustaceans found in the ocean, mantis shrimp apparently possess the most mobile eyes in the animal kingdom, researchers have discovered.
To mantis shrimp, the world looks a lot different than it does to everyone else. These small marine critters are endowed with amazing color vision and are able to see in both ultraviolet and infrared spectrums. The eyes of the mantis shrimp carry 16 types of color-receptive cones; by comparison, human eyes only have three.
But that’s not all as revealed by a study published today in the Proceedings of the Royal Society B. Unlike any other animals, which need to keep their eyes steady in order to see the world clearly and without blur, mantis shrimp can see just fine without any level of gaze stabilization.
The research, led by scientists from the University of Bristol in the U.K., uncovered that mantis shrimp, scientifically known as Odontodactylus scyllarus, can move their eyes independently in all three degrees of rotational freedom: pitch (up-down), yaw (side-to-side), and roll (twisting about the eye-stalk).
This allows mantis shrimp to roll their eyes even while stabilizing in the horizontal direction without affecting their perception of the world, per a news release by the university.
For anyone else, attempting such a thing would result in immediate vertigo, since it would make “up” suddenly become “sideways.” But mantis shrimp are still able to “reliably and accurately follow the motion of a pattern that is moving sideways” no matter which position they roll their eyes or how fast they do it, explains the news release.
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“It would be like you tipping your head on its side, then back to normal and all angles in between all while trying to follow the motion of a target,” says study lead author Ilse Daly, from the university’s School of Biological Sciences.
To add to the confusion, the eyes of the mantis shrimp are mobile enough that “one eye could be oriented horizontally, while the other could be twisted completely through 90 degrees to be on its side,” Daly explains.
After such a confounding discovery, Daly’s team wanted to find out how mantis shrimp adapt their vision when the world appears to roll around them. The scientists performed a series of tests in which they introduced rolling stimuli to see whether mantis shrimp would roll their eyes to follow their surroundings.
The results revealed that “rolling has absolutely no effect on their perception of space at all: up is still up, even when their eyes have rolled completely sideways,” states Daly.
“This is unprecedented in the animal kingdom,” she points out.