The red-bellied frog, endemic to Costa Rica, whose scientific name is Craugastor escoces (Heredia Robber Frog) classified as extinct in 2004, has made a reappearance.

An endemic Costa Rican frog species, after being declared extinct in 2004, has made a shocking reappearance.

It was on the night of September 18, 2016, that Randall Jiménez and Gilbert Alvarado were focused on finding copies of the green-eyed frog (Lithobates vibicarius).

“It was a completely clear night, without rain, full of stars, with a full moon, that is, with all the conditions conducive to not seeing frogs,” said Alvarado and added: “In other words, we had had a very bad night until we saw it”.

Hidden in a cave located in the upper part of a ravine, in the Parque Nacional Juan Castro Blanco (Juan Castro Blanco National Park), the researchers found a red-bellied frog, whose scientific name is Craugastor escoces  (Heredia Robber Frog). It was an adult female about six centimeters long.

Since 1986 nothing was known about this species, ie there were no reports of their presence in the wild. In 2004, the International Union for the Conservation of Nature (IUCN) group of experts on herpetology decided to call it extinct and updated its database of the Red List of Threatened Species.

“The species is endemic to Costa Rica, that is to say, unique in the planet. So, at that time, it was its extinction was not only reported in the country but in the world,” Alvarado told La Nación.

According to the ICUN, the Heredia robber frog occurred on the volcanos Barva, Irazú, and Turrialba, of the Cordillera Central of Costa Rica, at elevations of 1,100  to 2,100 meters above sea level (Savage 2002). “Although it has been well studied and collected extensively, and was formerly abundant throughout its range, it has not been recorded despite extensive directed surveys since 1986. There have been no new records as of August 2007. A serious decline appears to have taken place and there is now considered to be no doubt that the species is extinct (F. Bolaños and G. Chaves pers. comm.)”

The ICUN says the most likely cause of its disappearance in suitable habitats is the disease chytridiomycosis, perhaps in combination with climate change or other, unknown, factors.

With the rediscovery of the red belly frog, researchers’ work is now focused on monitoring the (find) site and assessing the population dynamics of the species, its health status and how susceptible it is to environmental changes such as habitat disturbance, infectious diseases, climate change and pesticides.

Official data indicates that in Costa Rica there are more than 200 species of frogs and toads.

The Juan Castro Blanco National Park is known for a large number of water springs.

Ex situ conservation

Parallel to this work on the site, the researchers decided to keep the live frog instead of sheltering it in the collection as a scientific proof of their reappearance.

For this, conditions of temperature, humidity, and asepsis similar to those found in their habitat were recreated and kept in observation in one of the laboratories of the recently opened Center for rescue, research and conservation of amphibians of the Experimental Station Alfredo Volio Mata de la UCR, located in Ochomogo of Cartago.


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