The spate of amphibian deaths and deformities the world over has confused scientist for some time now. Among the various reasons to which this has been attributed are fungal infection, thinning of the atmosphere's ozone layer, ultraviolet radiation or loss of habitat. Now, researchers from the US Fish and Wildlife Service have launched a study to find out whether pesticides and other pollutants are responsible for the deformities, said a report in the Washington Post . Malformed frogs, toads, salamanders and their eggs from 43 sanctuaries in 31 states will be surveyed. In recent years, there has been a decline in the population of 230 native amphibian species.