Slide 1 of 21
Scientists are on the look-out for "lost amphibians" animals considered possibly extinct but that may be holding on in a few remote places. There may be up to 100 of them hiding in the world's forests.
Here are just a few of the many fascinating amphibian species who have not been seen for over a decade. Some may be lost forever, while others may still exist, hidden under rocks in a remote stream, waiting to be rediscovered.
Golden toad (Incilius periglenes), Costa RicaSlide 2 of 21
Golden toad (Incilius periglenes), Costa Rica
The Golden toad was last seen in 1989 and is perhaps the most famous of the lost amphibians. The species went from abundant to extinct in a little over a year in the late 1980s.
Golden toads were originally discovered in 1966 in western Costa Rica's Monteverde Cloud Forest, where populations of other amphibian species have also collapsed, a development thought to be linked to climate change and disease.Slide 3 of 21
Gastric brooding frog (Rheobatrachus silus), AustraliaSlide 4 of 21
Gastric brooding frog (Rheobatrachus silus), Australia
Gastric brooding frogs come in two species: Rheobatrachus vitellinus and R. silus (pictured above and last seen in 1985).
These frogs had a unique mode of reproduction: Females swallowed eggs, raised tadpoles in their stomaches and gave birth to froglets through the mouth.
The reason for the frogs' decline is unknown. Timber harvesting and the chytrid fungus are the main suspects.Slide 5 of 21
Mesopotamia Beaked Toad (Rhinella rostrata), ColombiaSlide 6 of 21
Mesopotamia Beaked Toad (Rhinella rostrata), Colombia
This frog with a distinctive pyramid-shaped head was last seen in 1914.Slide 7 of 21
Jackson's climbing salamander (Bolitoglossa jacksoni), GuatemalaSlide 8 of 21