This week thinking color dives in to take a closer look at a colorful crustacean with remarkable color vision. We have briefly visited the Mantis shrimp before in an earlier blog about color vision in the animal world but new research into this creature warrants a closer look.
Most animals have three color receptors. Each receptor is tuned to absorb a different hue of light. The most common hues are green, red, and blue light. The receptors send a signal to the brain which weighs a ratio from each receptor thereby producing color.
The Mantis shrimp is known to have a whopping twelve color sensors. This might have you jumping to the conclusion that this shrimp can see a myriad of colors inconceivable to the human mind. However, this is not the case according to new research. New studies suggest that the Mantis shrimp sees color in a different way not a different hue than the rest of the animal kingdom.
Researchers carefully trained a Mantis shrimp to associate different colored lights with food by altering the hue of the light associated with a snack they were able to measure the distance between wavelengths of light that the shrimp was a able to detect. The researchers found something remarkable. The shrimp, despite it’s twelve color receptors, could only differentiate wavelengths of light 25 nanometers apart. This is the difference between yellow and orange and far from the one to four nanometers discernible by the human eye.
If the Mantis shrimp is essentially all but color blind why do they have so many color receptors? Scientists are not entirely sure yet however, there is a fairly plausible theory. The twelve color receptors are not intended to identify different colors but to identify a few colors very quickly. It is believed that the eyes of the Mantis shrimp work almost like a targeting system on a fighter jet. Food or more importantly the color of food is processed extremely quickly by the shrimp thereby giving it an edge hunting for prey.