Whilst the mantis shrimp eyes have 12 different photoreceptors, the crustaceans cannot easily distinguishing colors, according to a new study.

 

The eyes of mantis shrimp (Haptosquilla trispinosa) have 12 parts. This enables the shrimp to perceive distance on its own through a process called trinocular vision, and can perceive circularly polarized light.

 

Mantis shrimp appear in a variety of colors, from shades of brown to bright neon colours, and they can reach 12 inches in length. They are found in many shallow, tropical and sub-tropical marine habitats.

 

The eyes of the shrimp confer many advantages. The eyes of mantis shrimp may enable them to recognize different types of coral, prey species (which are often transparent or semi-transparent), or predators, such as barracuda, which have shimmering scales.

 

However, despite the incredible vision, the crustaceans visualize colors very differently, and rather poorly, compared to all other animals. To test this theory, marine neuroscientist Justin Marshall of the University of Queensland in Brisbane, Australia, and his colleagues trained shrimp to recognize each of 10 different colors in the visible light spectrum, then tested their ability to discriminate between those and other colors. The results showed that the shrimp did quite badly in the tests, according to National Geographic.

 

The reason for their poor performance, the researchers suggest in a review by Nature magazine, is that the animals perceive color in an entirely different way than humans. Here, the shrimps may just be responding to the photoreceptor that is the most active, with each type of photoreceptor reacting to a specific color.