They're charismatic and cute, but the tree frogs that live in Cusuco National Park in Honduras are being decimated by chytrid fungus. The fungus has spread worldwide, causing hundreds of amphibian species to become endangered or even extinct. Biologist and National Geographic explorer Jonathan Kolby has set up HARCC, the Honduras Amphibian Rescue and Conservation Center, to study and treat these frogs. Some of the species are found nowhere else on Earth.