Because we can easily see colors around us every day, we might assume that every creature does too. But that is not so.
The question of whether animals can distinguish between colors has long, puzzled scientists. However, they have come up with some interesting answers as a result of thousands of experiments.
Dogs, for example, who have been so easily trained to respond to commands, to recognize people, and even to distinguish among musical sounds, have been found to be color blind. This was discovered when test animals were shown different colored cards and then given food after only one of them. This same procedure was repeated time and time again. Then only the food card was shown.
Since the dogs did not salivate, or produce saliva in the mouth, an indication that they knew food was coming, scientists concluded that dogs cannot distinguish between colors. However, in a similar experiment using musical tones before food, they did salivate, indicating their ability to respond to varying sounds.
Cats were put through similar tests, and were found to be color blind also.
Monkeys and apes have been put through many tests, and the results have shown that they can tell colors apart. A box with their food was painted a certain color, and empty ones painted other colors. These monkeys and apes soon learned exactly which color to pick out in order to open up the box and get their reward.
Some animals, such as horses, have been found to distinguish between green and yellow, but are unable to distinguish between red and blue.
Interestingly, there are less intelligent creatures who respond to colors as well. Bees are one of these creatures. Scientists have long wondered whether bees can tell flowers apart by their colors. One of the hundreds of experiments conducted involved the use of two cards on a table, a red one and a blue one.
A drop of syrup was put on the blue card and none on the red. This was repeated time and time again, and each time the bees would come to the blue card, even though its position was changed. Then came the big test. The blue card was placed on the table with NO syrup on it. And still the bees came! This proved that bees could tell colors apart.
Some fish can see colors too, distinguishing between red and green and possibly between blue and yellow.
Hens can distinguish between all the colors of the rainbow!
According to another site, WiseGeek, animals to see colors but not necessarily to the same extent we do. There are 3 primary colors of light; red, blue, and green. The cones in eyes are the color receptors and are tuned to one of these primary colors. Humans have all three kinds with each being broad enough to overlap allowing us to see hues between the colors. Some animals have only two or even one. Not all have the overlap either.
Dogs can’t tell the difference between green and orange and both look gray. Throwing an orange ball on a green lawn would pose a problem to a dog who loses track of it in motion. Cats have trouble with reds.
Many other animals and insects have varying levels of color reception. Some have no cones at all. They have better night vision and rely more on motion to pick out objects.