In 2019, the last known 14 Loa water frogs (Telmatobius dankoi) were evacuated from a swiftly vanishing stream in northern Chile. Now, after more than a year of meticulous care, they have produced 200 tadpoles.

“The zoo’s specialists not only nursed the animals back to health after they were discovered malnourished and near-death in the wild last year, but they have now succeeded in breeding a new generation of a species that has very nearly vanished,” Lina Valencia, Global Wildlife Conservation’s Andes conservation officer, said in a statement.

The frogs caught a ride in the cockpit of a commercial flight from their dwindling habitat in Chile’s driest desert to the National Zoo of Chile in Santiago. Once the frogs reached the zoo, experts there faced the challenge of recreating the water environment of their home stream and figuring out what to feed them.

“When we brought these animals to the zoo, I didn’t even know if they were going to survive the transfer from Calama on the plane to Santiago,” said Andrés Charrier, a rescue team member and herpetologist affiliated with the Chilean Herpetological Society.

Twelve of the original 14 frogs survived and are in good health today. The team noticed reproductive conditions in the frogs, such as changes in the skin of males and the weight of females, and in late October 2020, the frogs laid eggs.

“We put two couples together, and we got about 200 eggs. At the beginning, we didn’t know if the eggs were fertile or not, but we noticed right away that these eggs turn into larvae very fast. Fast,” Alejandra Montalba, director of the National Zoo of Chile, told Mongabay.

Now, the zoo is home to 200 tadpoles, and the team faces the challenge of raising these young into healthy individuals.

“Everything that we are getting now it’s new for science. It’s the first time that these particular species [has] reproduced in an ex situ condition,” Montalba said. “So we’re very happy, learning again, trying to discover what these tadpoles need … the food that they need and the nutritional requirements … but it’s a challenge.”

Considered critically endangered on the IUCN Red List of Threatened Species, the Loa water frog is thought to live only in one stream in Calama, Chile. In 2019, that stream had dried into little more than a mud puddle. Researchers believe fewer than a dozen Loa water frogs remain in their native habitat.

The goal for the captive Loa water frogs is to breed enough healthy individuals to release them back into to the wild.  But until they have a safe home to go to, they will remain in the protection of the zoo.

“Ultimately we need to work very hard to restore their environment because it’s pointless to breed them if they don’t have a home to go back to in the wild,” Montalba said in a statement.

The Loa frogs are the last of their species, but there are 63 other species of water frogs (Telmatobius spp.) known to science living Argentina, Bolivia. Chile, Ecuador and Peru. Many are endangered or threatened and all are considered microendemic, meaning they live in only one small location such as a particular stream or lake. Because they require such specific conditions for survival, they are especially vulnerable to threats from development, drought, pollution and disease.

“The story of the Loa water frogs is a cautionary tale,” Don Church, president of Global Wildlife Conservation, said in a statement, “one that should spur us to action for all other water frog species before they also potentially decline to only a few individuals left.”

The most famous of the water frogs is perhaps Romeo, “the loneliest frog in the world” as he is the last known male Sehuencas water frog (Telmatobius yuracare). However, in 2017, Romeo was united with Juliet, the last known female of the species. The two are now living together, and the hopes of their species hinge on their successful romance.

The Museo de Historia Natural Alcide d’Orbigny in Bolivia, where the star-crossed lovers live, recently released a letter of encouragement from Romeo to the Loa water frogs in Chile.

“Humans got us into this mess,” the letter says, “but since your human friends at the zoo are like mine at the museum and all over the world, you’ll know that so many of them are committed to fixing this mess. So for all of these reasons, don’t give up!”

Banner image of a Loa water frog at the National Zoo of Chile. Photo by the Metropolitan Park of Santiago Parquemet.

Liz Kimbrough is a staff writer for Mongabay. Find her on Twitter @lizkimbrough

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