Emanuele Biggi / Bear-hearted glass frog (Hyalinobatrachium colymbiphyllum) resting on leaf, Panama.

Emanuele Biggi / Talamanca glass frog (Hyalinobatrachium talamancae) male guarding frogspawn attached to underside of leaf, Veragua Rainforest, Costa Rica.

Joel Sartore / Photo Ark / Fleischmann's glass frog (Hyalinobatrachium fleischmanni) portrait, Toucan Rescue Ranch, Costa Rica. Captive.

Emanuele Biggi / La Palma glass frogs (Hyalinobatrachium valerioi) mating pair, on a leaf with egg-clutches from previous matings nearby. The males stay and defend the eggs, even mimicking them in colouration to act a...

Roman Willi / Reticulated glass frogs (Hyalinobatrachium valerioi) pair in amplexus, Osa Peninsula, Costa Rica.

Roman Willi / Reticulated glass frog (Hyalinobatrachium valerioi) male, guarding egg mass, Osa Peninsula, Costa Rica.