This is Side Door, a podcast from the Smithsonian with support from PRX.

I'm Helima Shaw.

Frogs are really cool.

They are the sound of the rainforest at night.

This is Brian Grottwick.

Gratwick is a conservation biologist who studies frogs at the Smithsonian Tropical Research Institute in Panama. and he loves

loves hiking to learn about them. Just an incredible chorus of sounds

going through the night of all of these overlapping

different species.

Frogs live along warm tropical rivers,

deep in Panama's national parks.

They have all of these different calls from high-pitch chirps to long trills,

to gloops.

You hear some of the glass frogs and you can never find them,

but you can hear them up there making it then to right here by the stream you have

Little dark frogs making a really big racket and some of these Panamanian rocket frogs have a really trill call it

sounds like a little bird all along the streams and wherever you go looking for frogs, you tend to find them.

These soundscapes give Gratwick hints that these dense tropical forests and his amphibian friends are happy, healthy.

So when you had the conditions just right, it was really, it was really magical and

get just a huge, huge chorus of song and sound and activity. All these frogs

coming out trying to breed make their way in the world.

But his career has been shadowed by a growing threat,

...