Brookfield, IL —Behind the scenes at Brookfield Zoo Chicago, a record-breaking conservation milestone is helping secure the future of one of the world’s most imperiled amphibians. Months of meticulous care and coordination enabled Brookfield Zoo Chicago to successfully breed and raise 12,244 Puerto Rican crested toad tadpoles to be released in the wild, supporting species recovery efforts.
This marks Brookfield Zoo Chicago’s largest tadpole count from a single breeding cycle. Over the last decade, the Zoo has contributed nearly 40,000 Puerto Rican crested toad tadpoles to island-wide recovery efforts led by the Puerto Rican Crested Toad Conservancy (PRCTC) in partnership with the Puerto Rico Department of Natural and Environmental Resources (DRNA), the U.S. Fish and Wildlife Service (USFWS) and 16 accredited zoos and aquariums.
“Conservation work like this can be incredibly detailed and time-consuming, but that’s what makes these milestones so meaningful,” said Mike Masellis, Brookfield Zoo Chicago lead animal care specialist. “From carefully coordinating breeding pairs to hand-counting thousands of tadpoles and tracking toads in the field, every step plays an important role in helping restore this species. Our hope is that years from now, some of these tadpoles will return to the breeding ponds as adults and continue establishing future generations in the wild.”
The Puerto Rican crested toad is the only toad native to Puerto Rico and was once thought to be extinct in the wild. Today, the species persists through one of the world’s longest-running amphibian reintroduction efforts but remains listed as endangered by the International Union for Conservation of Nature (IUCN), threatened by the USFWS and endangered by DRNA. Primary threats include habitat loss, invasive species, rising sea levels and saltwater intrusion into breeding wetlands. The last naturally occurring population remains in the Guánica Commonwealth Forest in southwestern Puerto Rico.
Each year, breeding is carefully timed to align with Puerto Rico’s rainy season, when survival conditions are highest for tadpoles released into the wild. The months-long process involves close coordination with conservation partners to manage recommended breeding pairs for population biodiversity and mimic seasonal environmental changes to encourage breeding behaviors. Once counted and transported to Puerto Rico, tadpoles are placed into managed aquatic habitats where they are monitored through metamorphosis before dispersing into the surrounding landscape.
Last fall, two Brookfield Zoo Chicago animal care specialists traveled to Puerto Rico to support the PRCTC’s field conservation efforts at a release site. Working alongside conservation partners, the team spent a week monitoring toads to better understand habitat use, predator pressures and environmental conditions affecting survival after reintroduction.
Brookfield Zoo Chicago currently cares for about 20 Puerto Rican crested toads, most of which are cared for behind the scenes as part of conservation efforts. Earlier this year, guests were able to see two of these toads on habitat in The Swamp for the first time, offering a new opportunity to connect with a species that has gained global recognition in recent years. Millions of fans were introduced to Puerto Rico’s only native toad as a visual part of Puerto Rican artist Bad Bunny’s Grammy Award-winning album DeBí Tirar Más Fotos .
Guests can learn more about Puerto Rican crested toads and Brookfield Zoo Chicago’s conservation efforts by visiting The Swamp , watching the latest episode of Wild Rounds with Dr. Mike and exploring more at brookfieldzoo.org/animals/puerto-rican-crested-toad .
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About Brookfield Zoo Chicago: Connect. Care. Conserve.
Since 1934, Brookfield Zoo Chicago has been a global leader in animal well-being and conservation, inspiring conservation leadership by connecting people with wildlife and nature. The Zoo is a private nonprofit organization that operates on 235 acres of land owned by the Forest Preserves of Cook County and is home to more than 3,500 animals representing over 500 species—including many of Earth’s most endangered. Brookfield Zoo Chicago was the first zoo in the world to be Humane Certified™ by the American Humane Society for the care and welfare of its animals, and is an accredited member of the Association of Zoos and Aquariums, the Alliance of Marine Mammal Parks and Aquariums, and ArbNet. For more information, visit www.brookfieldzoo.org or follow @BrookfieldZoo on Instagram, Facebook, TikTok and Threads.