All in the Family
Let me express my gratitude for your June cover story ("Dinosaur Family Values"). I was beginning to fear paleontology had fallen off the face of the mass-media world. Let me also express the feelings of shock and dismay I had when I saw the caption title "Bringing Home the Brontosaur." At that point I keeled over in pain; the debate pertaining to the correct name of this large lizard plays a massive role in my life. But Bob Bakker has been one of my favorite paleontologists ever since the days when I used to watch Dinosaur! I assume he has a good reason for calling it a brontosaur. Now I come to the crux of my scathing letter. You refer to the dinosaur in question as both an apatosaur and a brontosaur. This is completely inexcusable. If you must call it a brontosaur, at least stick with your error for the entire article. An apatosaur and a brontosaur are the same creature, kind of like how Bruce Wayne and Batman are the same person.
Nashua, New Hampshire
Corey S. Powell, senior editor, responds: By general agreement, there is no such genus as Brontosaurus—it was an Apatosaurus body with the wrong head attached (kind of like Batman wearing Superman's head, to extend your analogy). We knew that. Bakker likes to use the nonstandard term brontosaur, which is colorful and familiar to nonspecialists, to refer to a variety of sauropod dinosaurs. We allowed the article to convey some of his language. We could not go into the whole story behind the misnamed Apatosaurus fossil excavated by Othniel Marsh in the 1870s, so one of our sources suggested we call it "the first named Brontosaurus"—which it certainly is, whatever the correct designation. A paragraph later, however, we wanted to refer to the unambiguous sauropod genus Apatosaurus. This is what happens when you try to strike a balance between simplicity and exactitude.
Sludge—Now Better Than Ever
I was startled to read the article about using wastewater sludge as fertilizer in June's R&D section ["Sludge: The New Fertilizer"]. This technology is decades old and currently practiced on a large scale in many areas. As far as I could tell from the article, Martin Adjei did not bring any new information to this area of sludge disposal.
Reporter Paroma Basu responds: We erred in implying that farmers no longer fertilize their crops with sludge. This approach has been restricted, however, by a paucity of data showing how well sludge competes with chemical fertilizers. Adjei's research determined which type of sludge works best and demonstrated that sludge actually improves the yield of Bahia grass, a common forage crop. He also found no evidence of lingering organic toxins or infectious microbes. These results should help alleviate widespread concerns about the safety of sludge-fertilized animal feed and produce.
Kathleen McGowan's article "Where Do We Really Come From?" in the May issue claims that biologists say the concept of race is biologically meaningless, presumably because "any large human population has about 85 percent as much genetic variation as the species as a whole." However, I recently read that African American men have a 150 percent greater incidence of prostate cancer than white American men. Presumably, the scientists who analyzed this data think that there are measurable differences among races.
Matthew A. Jacobs
Kathleen McGowan responds: The question of genes, race, and disease is hotly debated. The short answer is that there is no biological basis for "race" as we know it, but among populations there can be small but measurable genetic differences. It makes sense: People from neighboring regions will tend to share more DNA than people from distant lands. The amount of variation within any human population, however, almost overwhelms those average differences: Just about any gene variant found among the Lapps or the Malays will eventually be found in Nigerians as well. Our racial categories also don't correspond very well to global patterns of genetic diversity. Americans would lump all Africans together as "black" and consider the Swedes and the Syrians part of two different races, even though the differences between the Kalahari's Khoisan and the northern Masai, for example, are probably more significant.
Archaeologist Steven LeBlanc's hypothesis that prehistoric American Indian tribes were warlike is intriguing but unconvincing ["Ancient America's Culture of War," May] because he fails to address the key outcome of any war—who won? The passing reference to "the scenario he pieced together from oral legends of similar battles of the Hopi" is unsatisfying. Who would conquer a large group of people and then depart without a trace? If the Zuni, the Laguna, or the Acoma are descendants of the conquerors, where are the oral histories and traditions of fierce fighters and glorious victories? Raiding parties are probable, but region-wide genocide is unlikely. Burned bodies in a kiva are a sure indication that a disaster was in progress. But the cremation of those recently deceased from plague seems as likely an explanation as war. Drought-induced famine and pestilence most likely caused the demise of the great pueblos, similar to the fate of their distant descendants 600 years later.
Seneca, South Carolina
Tim Folger responds: If LeBlanc is right, the Zuni, Laguna, Hopi, and other tribes now in the Southwest are not the descendants of conquerors—they're the descendants of people who survived the battles that depopulated most of the region several hundred years ago. All the above tribes have oral histories of warfare; many tribes maintain warrior societies to this day. As recently as 1857, the Pimas, who still live near Phoenix, fought a pitched battle against the Quechua, wiping them out almost to a man. As for the burned bodies found in the kiva at Salmon Ruin, the kiva wasn't the only structure that showed evidence of burning—most of the pueblo had been burned. If the cremated remains were those of plague victims, why were all of them children? Plague doesn't single out the young for death. And if the pueblos were abandoned during a famine, why would the inhabitants leave behind bushels of burned corn? It's commonly thought that "raiding" is distinct from and less deadly than "war." LeBlanc cites studies showing that prolonged periods of raiding and ambushes are more deadly than formal battles. Warfare casualties in the Southwest—and among prehistoric peoples in general—were anything but "modest."
Roots of Dependence
I am fascinated when scientists think they have found a "cure" for addiction ["The Biology of . . . Addiction," May]. What scientists do not take into account is that addiction to alcohol and drugs may have roots that are not biological. You have to consider what drives a person to use drugs and alcohol addictively before the physical craving is created in the brain. Thirteen years of associating with alcoholics and addicts has taught me that we are driven to use for many reasons, including a physical craving. While eliminating the physiological cause of cravings is a great idea, I fear it will have little permanent effect unless it accompanies a treatment for the psychological cause of addiction.
Philip E. Nahrgang
Blue Bell, Pennsylvania
"Unplugged" [April] gave some interesting examples of alternative energy possibilities, but I believe it missed the point (indeed the promise itself) of energy conservation. With their concentration only on custom-built, suburban-type dwellings, these so-called energy choices are available only to wealthy Americans—at a time when the gap between rich and poor is widening daily and rates of homelessness and poverty are skyrocketing. How about building smaller units of low- or middle-income housing on the principles described in the story, relieving the cost of utilities for those who need the help most, as well as creating surplus clean energy for the surrounding communities? This is not simply a humanistic idea but also an economic one. I doubt corporations like Centex Homes and ConSol are going to find much demand for sensible energy use in suburban California. For natural power to become more prevalent, it must be offered to those who are most interested in its benefits.
Jamie E. Limbach
San Francisco, California
In May's NeuroQuest, we misidentified vision researcher Baingio Pinna, who coauthored the theory behind the Pinna-Brelstaff illusion. In June's Bogglers, we stated that there are 92 naturally occurring elements; of the first 92 elements, elements 43 and 61 are not found in nature.
The companion Web page for the three-part PBS series Race—The Power of an Illusion
addresses the science of racial differences and the paucity of science behind some of our society's intractable beliefs: www.pbs.org/race