How do we know which animals are color blind?
See where Alatea sed “The researchers..?” that’s the main reason we know which animals are color blind, researchers tested them. Sometimes the research was general just to find out which animals were and which were not, because someday somebody might have a specific reason to know. Other research was specific, maybe to find out if maybe chickens can find more food if it is a certain color. Some of it was research into anatomy, physiology, etc just to figure out how things work and if any of it applies to humans, like curing color blindness. One way of determining if an animal can tell various colors apart would be to require the animal to select, by pecking or pressing, a certain colored square to get some reward, like food. The test could get more and more precise by using colors more and more alike, various shades of red for example. It is important that the same material is used for a base for the colors, and that the colors are as alike in all ways except wave length, that is they
