Seven new species of tree frogs in Madagascar's rainforests are notable for their otherworldly, high-pitched whistling calls.

B. kirki, B. picardi, B. siskoi, B. janewayae, B. archeri, B. pikei, and B. burnhamae live in Madagascar's rainforests.

Madagascar is a place of biological wonders, an island brimming with life forms that exist nowhere else on Earth. It’s home to around 9% of the world’s frog species, and new discoveries are made frequently. But there’s a dark undercurrent to these findings — many of these species, including the new tree frogs, live in habitats that are shrinking.