Forty percent of all the frogs in the world are in danger of extinction, according to the Smithsonian Institution. Pollution, pesticides, climate change and now a fungus are taking a toll on this diverse group of amphibians. Until recently, the central rain forest of Panama was rich in frog species. Smithsonian conservationist Brian Gratwicke is directing a campaign to save and reproduce in captivity some of the world's most endangered frogs. VOA producer Zulima Palacio visited Gratwicke in th