What's Killing Off The Frogs?

Frogs, salamanders, and other amphibians are mysteriously dying all over the world, and no one can figure out why. CBS News Correspondent Eric Engberg filed this first-person report about efforts to solve this scientific mystery.

It is not easy to kill off a frog. Amphibians as a group have existed on Earth for 350 million years, so the phenomena thatÂ's killing them must be something that has happened fairly recently.

For now, the scientists have no answers but several clues. One big part of the mystery is that many of the deadly population losses are happening in pristine areas like national parks, far removed from the pollution of the cities.

Several possible causes are now being kicked around, and many of the experts believe that different factors are responsible for the deaths, depending on location.

The first potential culprit is ultraviolet rays coming through the damaged ozone layer. Scientists believe the UV rays are damaging frog eggs and juvenile frogs. In fact, one of the reason amphibians may be more vulnerable to environmental effects is that they pass through one or more metamorphoses on their way to adulthood.

But it is also true that ultraviolet has been ruled out in some places where frog extinctions have occurred. So scientists are looking at air pollution, water quality, and fertilizer and pesticide run-off as potential causes.

At one government test facility in Maryland, scientists spray different types of pesticides on a frog-filled pond to see if thereÂ's an effect. In some cases, the animals start being born with deformities.

Government support for a crash program to save the amphibians has had only disjointed support in the U.S. and other countries. But now Interior Secretary Bruce Babbitt has decided to make amphibians a priority issue.

He believes the government can help, not by spending a huge sum on research, but by coordinating the work that scientists are already doing in the field.
Droegge notes, "Basically, the way amphibians work is theyÂ're little sponges. They soak up the water, and they soak up the air directly through the skin rather than through lungs. They have lungs, but theyÂ're not as important to them as ours are to us. So, theyÂ're pulling in the parts of the environment, then theyÂ're dying."

TheyÂ're diseased, and malformations are occurring, and theyÂ're disappearing out of the place. At the same time, we drink that water and we breathe that same air. And we have to begin to wonder whether the problems the amphibians are having doesnÂ't transcend the species...to wonder if this is something that raises a human health concern."

But Ken Dodd, my guide through the Great Smokies, says we have a responsibility to save the frogs and salamanders, even if humans arenÂ't threatened by whatÂ's threatening them.

"They have been here a lot longer than we have," he told me, "and I donÂ't think humans per se have any right to be so arrogant as to come in and do something to the environment that eliminates whole groups of animals," Dodd said.