Vocal Sac-Brooding Frogs: Rhinodermatidae

DIFFERENT SPECIES DIFFERENT CALL

Until scientists took a closer look, they thought Darwin's frog was the only member of the vocal sac-brooding family. One of the clues they used to decide that the frogs were actually two different species instead of one was that some males were making one type of call and others were making a different-sounding call. The call is very important among frogs because females use it to find males who are ready to mate. If a male's call is different—even if he looks just like every other male frog in the forest—a female will not answer his call and will not mate with him. An important requirement for animals to be of the same species is that the males and females must recognize each other as possible mating partners.