“Frogs matter - they play a vital role in the food chain, and some have been found to produce chemicals that cure human diseases. But a fungus dubbed "the amphibian smallpox" is making many species extinct. So scientists are mounting a rescue operation.
It's the middle of the night in the rainforests of central Panama.
Biologist Brian Gratwicke slogs through a stream with a group of researchers looking for little green blobs sitting on leaves.
"Anything that makes the leaf hang unusually," he says.
A colleague spots a pair of tiny eyes gleaming in the beam of a torch. But it's a false alarm - probably just a spider, and spiders are not the team's quarry.
The little green blobs they are looking for are frogs, and after 90 minutes in the jungle, they have yet to find a single one.
It might just be bad luck, but probably not. Frogs around the world are in decline. In recent years, scientists have documented frog population decreases of up to 80% in some areas.
Habitat loss, climate change and pollution, are all playing a role in the disappearances.
Another culprit is "chytrid" - a virulent fungal disease, thought to have originated in Africa, that's spreading around the globe.
In parts of Central America the fungus is moving at around 20 miles (32km) a year…”