It's not easy being green--or blue, for that matter. Frogs, toads and other amphibians are disappearing at a rate that has scientists concerned. A report released this month says that about one-third of the world's species of amphibians are vulnerable or endangered. "What we're seeing is unprecedented," says lead researcher Simon N. Stuart.
Researchers say there are many reasons for the decline, including habitat loss. The factors that can't be easily explained cause the most worry. Amphibians are more sensitive to pollution than humans are. Fewer salamanders and frogs could be an indication of air or water pollutants. The study has given scientists valuable information as they hunt for the causes of this troubling trend.