Hikers in Papua New Guinea heard the “harsh” sound coming from the treetops and followed it. Take a look at what they discovered.

A rainforest, whether tropical or temperate ... Discovered only in 2009, Darwin’s bark spider can be found in Andasibe-Mantadia National Park. These frogs are the only ones to give birth to living ...

The team collected over 130 of these Ecuadorian tree frogs by combing museum archives, searching the rainforest and raising some eggs in captivity, the study said. A pattern began to emerge.