CHICAGO -- Thousands of endangered tadpoles that were bred at Chicago's Brookfield Zoo are now headed to their native land.
More than 8,000 Puerto Rican crested toad tadpoles will be released to the central mountain range of Puerto Rico.
It's part of a conservation program by the Chicago Zoological Society.
Their aim is to help repopulate the species.
This species of toad is the only one native to the country. It faces threats from rising sea levels, habitat alteration, fragmentation, and invasive species, according to experts.