Why amphibians are at risk ?
A mphibians have received much attention during the last two decades because of a now -general understanding that a larger proportion of amphibian species are at risk of extinction than those of any other taxon. Why this should be has puzzled amphibian specialists. A large number of factors have been involved, including most prominently habitat destruction and epidemics of infectious diseases; global warming also has been invoked as a causative factor. What makes the amphibian case so compelling is the fact that amphibians are long-term survivors that have persisted through the last four mass extinctions. Paradoxically , although amphibians have proven themselves to be survivors in the past, there are reasons for thinking that they might be vulnerable to current environmental challenges and, hence, serve as multipurpose sentinels of environmental health. The typical life cycle of a frog involves aquatic development of egg