"Being colorblind can be a good thing":

Researchers studying capuchin monkeys in the forests of Costa Rica have shown that colorblind individuals are better at detecting camouflaged insects than are those that see a wider spectrum of colors. The finding is the first evidence from the wild that colorblindness confers advantages during foraging.

...The findings make sense, says Nathaniel Dominy, a primatologist at the University of California, Santa Cruz: "If you reduce the amount of color information coming into the brain, your brain may be better able to detect shapes, contours, and contrasts." That may be why these color-challenged monkeys have managed to stick around in the gene pool, he says.

One of my partners is an excellent mammographer, and he also happens to be color-blind. I would love to know whether this was correlated with his ability to detect subtle breast cancers on the often-challenging grey-scale mammogram images. (Via SciTech Daily.)