What colors can animals see ? Is the world more brightly colored or duller to animals than it is to us ? To find out the answers to these questions scientists have used a method of training the animals to come to different colors, which is similar in principle to the method used in studying the sense of hearing in animals.
Let us take bees first of all, partly because more exact scientific research has been done on the color-sense of bees than of almost any other animal. It is especially interesting to know what colors bees see because these insects visit flowers to get sweet nectar from them to make honey, and in doing so the bees incidentally carry pollen from flower to flower. On the face of it, it would seem very likely that bees are attracted to flowers by their bright colors. But possibly it is the scents that attract the bees, or perhaps it is both color and scent. So, among other things, we want to know whether bees can really see the colors of flowers, and if so, what colors they can see. Exactly how is this found out ?
A table is put in a garden, and on the table a piece of blue cardboard is placed, on which there is a watch-glass containing a drop of syrup. After a short while bees come to the syrup and suck some of it. The bees then fly to their hive and give the syrup to other bees in the hive to make honey. Then they return to the feeding place which they have discovered. We let the bees go on doing this for a while, after which we take away the blue cardboard with the syrup on it. Instead of this card we now put on the table a blue card on the left side of the first feeding-place, and a red card to the right of the first feeding-place. These new cards have no syrup on them but only an empty watch-glass lying on each. Thus, the blue card is on the left, the red card on the right, and there is nothing where the first blue feeding-card used to be. After we have arranged these new cards, we have not long to wait. Very soon bees arrive again, and it can be seen that they fly straight on to the blue card; none go to the red card.
