While all other amphibians wither and are unable to survive in salt water environments, crab-eating frogs (Fejervarya cancrivora) in Indonesia have evolved to survive and thrive in it.

From Biodiversity Science:

Thin permeable skin is both the cornerstone and the millstone of amphibian evolution. On the one hand skin provides a useful site for gas exchange; on the other, free water movement across skin confines amphibians to freshwater. Indeed, of the 6,500 recognised amphibians, only the crab-eating frog can enter the sea.

Unlike other amphibians, which rapidly dehydrate in seawater, crab-eating frogs absorb urea across their urinary bladder in order to eliminate the osmotic gap between body fluids and seawater. Seawater acclimation requires several days, leaving the frogs with two equally disagreeable options — they can take up salt and lose water to the sea, or face desiccation on land.

This gave scientists the option to to study very unique amphibian. To read the rest of the article, click here.