"We humans, in comparison with birds, are about the same as color-blind versus people with normal vision, " says evolutionary biologist Mary Caswell of Princeton University (USA). There are only three types of light-sensitive cones in our eyes to respond to blue, red, and green. And the same hummingbirds have another type of cones to interact with ultraviolet light. Therefore, they are called tetrachromats.
The most interesting thing is that birds do not just see in a wider wavelength range, they are also able to distinguish between combined colors. For example, ultraviolet and red or ultraviolet and green. It is even difficult for us, humans, to imagine how this, in principle, might look like. Hummingbirds, according to preliminary data, can distinguish at least five types of such combinations.
Caswell's team has conducted thousands of experiments that have convincingly proven the hummingbird's ability to see colors beyond humans. And not just to see, but to very accurately distinguish shades, solving small puzzles that scientists have prepared for them.
In another study, which affected the plumage of 1, 000 different species of birds and 2, 400 species of plants, it turned out that the surface structure of more than a third of them is such that it reflects light in the area of the invisible spectrum. That is, at least a third of living nature has a coloring that a person will never see, and therefore cannot be used in his activities. This is roughly like assessing historical events only by black and white photo chronicle, which cuts out many important details associated with different colors.