Letters from the May 13, 2006, issue of Science News

Now hear this

Unless the writer is deliberately implying an archaic theory of evolution in “Can you hear me now? Frogs in roaring streams use ultrasonic calls” (SN: 3/18/06 p. 165), the statement “Ultrasonic perception may have developed as the frogs (Amolops tormotus) struggled to hear each other . . .” cannot be true. That’s not how natural selection works.

John Wymore
Albuquerque, N.M.

Frogs that could hear frequencies higher than the water’s roar might have had an advantage. “Struggled to hear each other” shouldn’t be interpreted as “struggled to evolve.” Indeed, evolution doesn’t work that way.—S. Milius

No direction home?

In “Unique Explosion: Gamma-ray burst leads astronomers to supernova” (SN: 3/4/06, p. 133), the author states that the observed supernova was “one of only a handful . . . heralded by a burst of gamma rays.” Isn’t that because gamma-ray bursts from core-collapse supernovas are directional, along the axis of rotation? Was GRB 060218 “unique” because it produced a burst of gamma rays or because its axis was pointed our way?

Peter Wilson
Simi Valley, Calif.

Gamma-ray bursts are directional, but less than 1 percent of supernovas are associated with gamma-ray bursts. Moreover, the supernovas are fainter, and therefore harder to detect, than gamma-ray bursts. That’s why only a few of these supernovas have been detected.—R. Cowen

Say no to drugs

I wouldn’t allow a child of mine to receive SSRIs for treatment of depression, unless that depression were truly crippling and my child required in patient care and a 24-hour suicide watch (“Prescription for Controversy,” SN: 3/18/06, p. 168). The marginally lower effect of talk therapy alone, while presenting half the risk of committing suicide and imposing no unknown long-term pharmacological side effect, makes this decision a no-brainer to me.

David P. Vernon
Tucson, Ariz.