Researchers have discovered seven new species of tree frogs that make otherworldly calls in the rainforests of Madagascar. Their strange, high-pitched whistling calls sound more like sound effects ...

Most male frogs want their mating call to stand out from the crowd, and they do that by calling when nobody else is. This makes sure that the females hear them loud and clear, and know where they are.

Hiking through the dense rainforest of Madagascar, scientists heard a series of “otherworldly” sounds. The “somewhat bizarre” calls came from several “cute” creatures living near streams. They turned ...