Why do humans not have blue or green hair? Insects have these hues, birds are so plumaged, and even the mandrill baboon has blue pigmentation on the face. We humans have blue or green eyes, so the ability to produce the colors in question is present. So why, oh why, must we resort to artificial means to achieve blue or green hair? And I don't mean the sort of "blue rinse" fashionable for ladies of a certain age. I mean royal blue, sky blue, even Wedgwood blue. As for green, I rather fancy a shimmering kelly green. --Al in Beantown
Al, if you were in high school now you would be on the cutting edge. There are two lines of thought on why green, blue, etc, don't naturally occur. The first is that all kids born with such hair due to random mutation were spontaneously murdered by their parents, obviously a highly retro point of view. The second is that green and blue confer no reproductive advantage, a contention that, at the risk of sounding a little retro myself, is not going to get any argument from me.
Beyond that it is difficult to say anything definite. As one member of the Straight Dope Science Advisory Board plaintively notes, "Why don't humans have beaks?" However, the SDSAB has come up with the following thoughts:
(1) In animals bright colors are a means of sexual display. For this purpose we humans have thong bikinis and bicep tattoos or, more seriously, enlarged mammary glands and (potentially) long head hair of whatever color. Hair color, it is widely thought, originally served the purely practical purpose of shielding us from the sun, which is why peoples indigenous to northern climates tend to be blond (less of the protective pigment melanin) while those living farther south tend to be brunettes. That does leave us with the difficulty of explaining red hair, but we'll leave that to another day and, with luck, another columnist.
(2) Hair-color variation may be more complicated than you think. Mark Lomas of Cambridge, England (Cecil has been fooling around on the Internet again), offers the following illustrative tidbit: a disproportionate number of the cats found run over by cars on British roads are white. Why? Turns out white cats are usually deaf and are saved from otherwise certain extinction only by the humans who breed them. Lomas's point is that the genetic change necessary to obtain blue or green hair in humans might have disastrous side effects that would prevent the trait from being passed on.
But there may be more to it. Lomas notes that green and blue hair in humans is not merely rare, it's unheard of. That suggests that adding another shade to the usual human hair-color palette might require simultaneous changes to multiple genes or a succession of mutations spanning several generations, both highly unlikely events. Darn.
What is quanza/kwanza/kwaanza? From a two-minute discussion at a party I gather it is some sort of multiday African American celebration around Christmastime, but exactly what is being celebrated, or even how it is spelled, did not make it through the din. Surely you can help on both counts. --J. McCurdy, Western Springs, Illinois
It's Kwanzaa, white eyes. It's a seven-day celebration of African heritage extending from December 26 through January 1. Started by LA black activist Maulana Ron Karenga in 1966 in the aftermath of the Watts riots, Kwanzaa is modeled on African harvest festivals (the name means "first fruits" in Swahili). December is a little late for the harvest of course, and the timing suggests that the celebration is supposed to be an alternative to Christmas. Not true, supporters say; most celebrators, largely middle-class African Americans (plus a lot of African Canadians, African Caribbeans, and even African Africans), observe both Christmas and Kwanzaa. Each day of Kwanzaa is devoted to one of seven principles: umoja (unity), kujichagulia (self-determination), ujima (collective work and responsibility), ujamaa (cooperative economics), nia (purpose), kuumba (creativity), and imani (faith). There are various family rites and, on December 31, a feast called karamu, often a major social event. The big challenge in the eyes of many: keeping Kwanzaa noncommercial. I note that a 1989 article on the subject in Essence concludes with a lavish photo spread of folks decked out in fancy Kwanzaa duds, suggesting that for a jaded few the celebration has an eighth principle: moola.
Art accompanying story in printed newspaper (not available in this archive): illustration/Slug Signorino.