'Groundbreaking' record number of endangered tadpoles sent to Puerto Rico

A ‘groundbreaking’ record number of endangered tadpoles were released into the wild in late October thanks to the San Antonio Zoo.

The Zoo's Herpetology team sent over 18,000 Puerto Rican-crested toad tadpoles on Oct. 26 to be released into the wild in Los Conventos, Guayanilla, Puerto Rico. This year's release is more than triple last year's record of around 5,000 tadpoles.

The tadpoles were released the next day into ponds monitored by the Puerto Rican Department of Natural and Environmental Resources (PRDNER), the U.S. Fish and Wildlife Service (USFWS), and private NGOs. San Antonio Zoo began breeding Puerto Rican Crested Toads in 2010 and in the last twelve years, it has released 34,372 tadpoles into their Puerto Rican habitat.  

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(San Antonio Zoo)

"The first time San Antonio Zoo began contributing to the program as a breeding institution was 2010," said Craig Pelke, director of Ectotherms at San Antonio Zoo. "Since that time, there had been good success…any time you can place a critically endangered species back in the wild is good. However, we wanted "great."

Once believed to be extinct, Puerto Rican crested toads have only one remaining population, fluctuating between 1,000 and 3,000 adult toads in the Guanica National Forest of southern Puerto Rico. The Puerto Rican Crested Toad Conservancy (PRCTC) works to increase that population by conducting island-wide education outreach, protection, and restoration of existing habitats, new ponds to support multiple self-sustaining metapopulations, and now reintroducing tadpoles back into their native environment, says the San Antonio Zoo. 


In San Antonio, the Puerto Rican Crested Toads (PRCT) are individually identified and tracked; the toads are then kept in isolation in a bio-secure room from the general zoo population to prevent cross contamination and possible illness, says the Zoo. Once the tadpoles are hatched, the herpetology team carefully hand counts them before being gently packaged and shipped overnight to Puerto Rico.  

 "A couple of years ago, we decided to revamp our entire operation across the board by improving housing, husbandry, and diet. In 2021 we ended up breaking previous records by over half, and this year we again broke our institutional record and ended up producing more tadpoles than all our other years combined!" said, Pelke. 

To learn more about the Zoo's conservation efforts and other programs, click here