The extremely rare Bolivian glass frogs have been spotted for the first time in nearly 18 years.

3 Bolivian Cochran frogs, which have translucent skin, were spotted by conservationists earlier this month in a national park.

The tiny amphibians only weigh around .7 to .8 grams and measure around 19 to 24 mm.

Glass frogs are found in Central and South America.

These extremely rare glass frogs have skins that are translucent, which allows humans to see their internal organs.

Conservationists found the Bolivian Cochran frogs (Nymphargus bejaranoi) in Carrasco National Park, which is located on the east part of Cochabamba.

The discovery was made during a mission to rescue reptiles and amphibians whose habitat is threatened by a hydroelectric project.

Members of the search and rescue team said, “The rediscovery of this species fills us with a ray of hope for the future of the glass frogs – one of the most charismatic amphibians in the world – but also for other species.”

The frogs were taken to the K’ayra amphibian conservation center, which is located at the Alcide d’Orbigny museum.

In efforts to increase the population, scientists will be encouraging the frogs to breed.