Scientists wanted to know why many animals have two types of color receptor cells in their eyes (dichromats), while others, including humans, have three (trichromats), and how this influences their capability to identify camouflaged prey.
To over 30,000 online game players, they showed photographs of camouflaged nightjar birds or nests containing eggs, either imitating the limited colors seen by dichromatic predators or in normal color.
Dichromats with red-green color blindness easily find their camouflaged prey as color interferes with the animals’ capability to identify camouflaged objects.
So, the team was surprised to find that trichomats were faster than the simulated dichromats in finding the nightjars and eggs.
However, large differences were found in the degree of influence made by various types of camouflage (like brightness and pattern) on dichromats' capture times.
Over the egg-hunting game’s period, faster improvements in the dichromats were found than in trichromats that by the end of the game, both performed equally well.
The scientists therefore arrived at the conclusion that though dichromats can see only limited colors, they are better at differentiating between dark and light and at detecting concealed objects. This is an advantage for predators.