The class Amphibia contains over 6,300 known species, 54% of which live in the neotropical region. They cannot tolerate the high salt content of sea water and are therefore the only vertebrates not to have colonized marine habitats (Capula, 1989). The class is divided into three orders. The largest, Anura, is divided into approximately 30 families and more than 4,500 spe-cies, ranging in size from a few millimeters to a couple of feet in length, and found in nearly every niche on earth. They have four limbs, the hind limbs typically being larger and modified for leaping or climbing. Most are external fertilizers. These species are also vocal, making sounds that range from squeaks to barks. In lentic environments, anuran breeding occurs in water bodies ranging from ephemeral pools to large permanent lakes (Richter-Boix et al., 2006). Most species deposit their eggs or live larvae in aquatic envi-ronments; these go through a larval phase (tadpoles) characterized by in-tensive morphological transformation—metamorphosis—to the juvenile stage, with an adult appearance; they then continue growing until the re-productive stage.