Amazon Milk Frog (Trachycephalus resinifictrix) Amazon milk frogs are fairly large frogs, reaching sizes of 2.5 to 4 inches in length. Adult frogs are light grey in color with brown or black banding, while juveniles will exhibit stronger contrasts. As Amazon Milk Tree Frogs age their skin will develop a slightly bumpy texture.

The "milk" in the name comes from the milky colored fluid these frogs excrete when stressed.