The New Yorker, which is fast becoming a major source of scientific information for the layman, includes in the May 25 issue an article by Elizabeth Kolbert titled "The Sixth Extinction?" Kolbert ably discusses the previous Big Five die-offs on the planet and the history of controversy (now settled) about whether they happened at all. Then she moves into the extinction currently in progress, with special focus on frogs and bats.
My 1998 novel Maximum Light used then-current research on frogs deformed and/or made infertile by the estrogen-mimicking compounds found in many plastics. This is still a concern, but Kolbert's article features contemporary research on a different cause of frog extinction. Entire frog species are disappearing, sometimes from one year to the next, all over the world. And for once humans are not the cause -- although we may be a contributory factor.
The reason is a newly discovered fungus, Batrachochytrium dendrobatitis (Bd). "Batrachos" is Greek for "frog." Bd has apparently long infected African claw frogs, but without harming them. But in the 1930's, a doctor invented a pregnancy test based on the eggs of African claw frogs, and the creatures began to be exported. "In the nineteen-forties and fifties," Kolbert writes, "it was not uncommon for obstetricians to keep tanks full of the frogs in their offices."
The practice had died out by the time I ever saw an OB/GYN, but the fungus had escaped Africa. Bleach will kill it, but it's impossible to disinfect an entire rain forest. And Bd is lethal to most species of frogs. Without the inadvertent human help, it would have spread across the globe far, far more slowly -- or maybe not at all. By the end of this century, as much as 1/3 of the Earth's amphibian population could be gone.
In Panama, the El Valle Amphibian Conservation Center is trying to preserve living specimens of frog species before they're all dead. The goal is to maintain a breeding population of 25 males and 25 females of each species, in conditions safe from contamination. The frog extinction is spreading in waves around the globe, and the Center's director says he collected most of his specimens in a rush, "just as corpses were beginning to show up around El Valle."
I grew up in the countryside of upstate New York. I remember spring peepers everywhere, their chorus loud and cheerful. It's been several years since I've heard them at my father's house. Now, sadly, I know why.