> Most languages developed a word for the color red before > any other colors. Probably because blood is red and > uniquely present at the most dramatic tim

> Most languages developed a word for the color red before > any other colors. Probably because blood is red and > uniquely present at the most dramatic times of life. Red has high contrast against the backgrounds of natural scenes (greens, blues, browns, etc) and is distinguishable in a variety of lighting conditions. For this reason it is one of the standard "warning" colors used by the natural world. Moreover, plants have co-opted red for positive signaling, too: many fruits and berries are red. If that weren't enough, many mammals (including humans) use red hues for signaling emotional and sexual states. Discriminating red hues was apparently important enough that primates "re-evolved" a red-detecting cone in the retina, despite ancestral mammals losing a similar one earlier in evolutionary history.