Letters from the June 5, 2004, issue of Science News

Blackened reputation

Again, humans are implicated in the promotion and distribution of our own misery (“Medieval cure-all may actually have spread disease,” SN: 4/3/04, p. 222: Medieval cure-all may actually have spread disease). However, if bitumen was wrongly credited with darkening the skin of mummified remains, what caused it?

Robert Fizek
Newton, Mass.

The coating on the mummies was actually a rub made up of oils, spices, salts, and tree resins. These substances, particularly the resins, dried and darkened as they aged.—S. Perkins

Me and my monkey

When I was a teenager, I lived with a brown capuchin monkey (“Monkey Business: Do the quirks of capuchins make them creatures with culture?” SN: 4/3/04, p. 218: Monkey Business). Among other games, we enjoyed trading: his poker chips for my food. When he was out of poker chips, he would improvise by finding pebbles, paper, toys, and other household detritus to trade. When all was traded into my pile, he would give me his tail, feet, and hands by placing them, one by one, in my mouth. These pieces of him were mine to keep until I chose to release them. While a part was in my mouth, his focus was diffuse and disconnected from me and from himself (perhaps similar to the “trancelike state” mentioned in the article). After I released him, he would refocus on me and begin to negotiate the next exchange. He was an acutely intelligent individual, and I am very grateful for Susan Perry’s field study of capuchins.

Ann Guthrie
Fairborn, Ohio

Potent rodent

It should have come as no surprise that the rat’s DNA had “changed much more than the human genome had since the two species diverged from a common ancestor” (“Devil’s Lapdog Gets Its Due: The lab rat bares its DNA to biologists,” SN: 4/3/04, p. 211: Devil’s Lapdog Gets Its Due: The lab rat bares its DNA to biologists) considering how many more breeding cycles the rat has experienced since that time.

Joe Halton
Anacortes, Wash.

The shorter generation time of rodents can’t by itself explain the differences, according to the researchers.—J. Travis