Naked speed The article “Running barefoot cushions impact of forces on foot” (SN: 02/27/10, p. 14) says a lot about whether running barefoot is or isn’t healthier than running shod. Has anyone looked into which is faster? Henry Jones, Baton Rouge, La. “No,” responds Daniel Lieberman, a professor of evolutionary biology at Harvard University. But he does note that Abebe Bikila set a world record for the marathon at the 1960 Rome Olympics running barefoot. And Zola Budd set quite a few records running middle distances barefoot. “There is no theoretical reason why ba... (p. 31)

Hairy Ardi issue In the report on Ardi (“Evolution’s bad girl,” SN: 01/16/10, p. 22), the artist’s illustrations show her in fur. The fact that her purported descendants are relatively hairless has been popularized by Desmond Morris (The Naked Ape, 1967) and Elaine Morgan (The Descent of Woman, 1972). What is the paleoanthropologists’ evidence that Ardi had not yet shed her fur coat and gained the advantage of superior heat loss in tireless pursuit of game? Walter J. Freeman, Berkeley, Calif. Hairiness made sense for an early hominid species that lived in forests, had i... (p. 30)

Ancient graffiti Regarding “Graffiti on the walls in Pompeii” (SN: 01/30/10, p. 14), I remember reading some years ago about graffiti being discovered in Pompeii. There was even a symbol that researchers interpreted as a sort of “Kilroy was here.” Is this an on­going study? New sites? I wonder if there were other markings, such as height marks recording children’s growth? The article says “written” — were all of the marks scratched into the rock? Bob Wilson, Oakridge, Ore. Graffiti were first observed at Pompeii in the late 19th century. More than 11,000 insta... (p. 31)

To their credit In Tom Siegfried’s article, “The Top 10 science news stories since time began” (SN: 1/2/10, p. 2), No. 5 is “Watson and Crick elucidate DNA’s double helix structure, 1953.” I am annoyed that, as usual in articles about the early understanding of DNA, Rosalind Franklin’s name has been left off. Even Watson and Crick admitted that without her work they could not have been successful. Ted Coskey, Seattle, Wash. Tom Siegfried’s list of the Top 10 “science news favorites from the dawn of civilization” includes the comment that “analyses of new s... (p. 30)

Snack addicts The experiment outlined in “Junk food turns rats into addicts” (SN: 11/21/09, p. 8) seems to have overlooked an ingredient list. The junk foods fed to the rats were junky, to be sure, but which foods were the most addictive? Many junk foods are filled with alarming amounts of things like mono­sodium glutamate. Were the rats more responsive to the MSG-laden foods? Did they crave salt over sugar? Fat over starch? This article left me hungry for specifics. Drew Massey, Los Angeles, Calif. In the study, researchers fed the rats a mishmash of junky foods (th... (p. 28)

Thinking animals An interesting article, but the question of human consciousness seems no closer to solution in “Humans wonder, anybody home?” by Susan Gaidos (SN: 12/19/09, p. 22) than it did in Julian Jaynes’ The Origin of Consciousness in the Breakdown of the Bicameral Mind of 1976. It seems to me that all the mental abilities discussed do not show that humans can do something unique to our species, or show that we are more “conscious” than other species, but only that species display varying degrees of ability. For example, humans are not the only animals to make tools, ... (p. 31)

Well-tooled apes The fascinating article “Aping the Stone Age” (SN: 11/21/09, p. 24) led me to wonder whether researchers who work with chimps or other higher apes have ever introduced them to the modern tools used by humans, such as saws, axes, hammers or pliers. If so, it would be interesting to know whether the apes could grasp the tools’ purposes, employ them productively and/or demonstrate their utility to ape kin. Jack J. Friedman, Fort Lauderdale, Fla. Andrew Whiten of the University of St. Andrews in Scotland replies: An interesting question. Some studies have... (p. 31)

Outsized beaver Accompanying your recent article about giant extinct beavers (“Ancient beavers did not eat trees,” SN: 11/21/09, p. 10), there is an illustration that seems to show that the extinct beaver was about twice the length of a present-day beaver. I measured each from nose to the base of the tail rather than to the tip of the tail since the tails seemed so dissimilar. This suggests to me that the ancient beaver would have had close to eight times the mass of the present-day beaver, since width and height would likely also be doubled, yet the article describes an ancie... (p. 34)

Plan for a long stay Lawrence Krauss’ idea of staying permanently on Mars (SN: 10/10/09, p.4) is fascinating, but criticism by John F. Fay and Jeffry Mueller (Feedback, SN: 11/21/09 p.29) missed important information. Krauss too missed the best of all scientific comparisons. Regarding the travel to the American continent by the Pilgrims: the “capital P” Pilgrims did not expect it to be easy to live in the New World. But it was significantly harder than they expected when their ship ended up at a location much farther north than they had intended. The contention that the ... (p. 31)

Jovian scars Page 8 of the August 29, 2009, Science News shows a dark impact scar on Jupiter’s surface. Similar dark areas appeared when Comet Shoemaker-Levy 9 hit. Why are they dark? Clearly, we are not seeing any “subsurface dirt.” Also, the color cannot be due to some dark underlying gas. Could it be an enormous depression in the cloud cover, the bottom of which the light does not reach? Raul Pettai, Montville, N.J. Glenn Orton of NASA’s Jet Propulsion Laboratory in Pasadena, Calif., responds: Hard as it is to believe when you live on a planet where the dark stuff is... (p. 30)