News Release
Contact: Sondra Katzen, Public Relations, 708.688.8351,
October 14, 2022
 NOTE: Scroll to end of press release to download photos.

Thousands of Endangered Crested Toad Tadpoles from Brookfield Zoo to be Released
to the Wild in Puerto Rico

Brookfield, Ill. — In an effort to help increase the wild population of the Puerto Rican crested toad, this week, the Chicago Zoological Society has sent just over 8,200 tadpoles that hatched at Brookfield Zoo to be released to the wild in Puerto Rico. The species, which is listed as endangered by the International Union for Conservation of Nature and Natural Resources, is the only toad native to Puerto Rico.

Since 2015, the CZS, which is accredited by the Association of Zoos and Aquariums (AZA), has provided nearly 21,000 tadpoles for release to the wild. In 1984, the Puerto Rican crested toad became the first amphibian Species Survival Plan (SSP) program under the AZA. The program was restructured to the Puerto Rican Crested Toad Conservancy (PRCTC) in 2021. The nonprofit is a consortium of zoos, individuals, and organizations working together for the long-term survival of the species in the wild.

Currently, 20 institutions, including Brookfield Zoo, participate in the conservation efforts for the Puerto Rican crested toad, which is the longest-continuously running reintroduction program for any amphibian species. Managed by PRCTC and its partners, the U.S. Fish and Wildlife Service (USFWS) and the Puerto Rico Department of Natural and Environmental Resources (PRDNER), collaborators have collectively released 650,000 tadpoles to Puerto Rico since 1984.

“The time, care, and efforts of our animal care staff to provide the crested toads at Brookfield Zoo a unique habitat suitable to reproduce and help to repopulate the species in its native land is a testament to their dedication,” said Andy Snider, curator of herpetology and aquatics for the Chicago Zoological Society. “We are proud to be able to collaborate in this important conservation effort for a species that was once thought to be extinct.”

Easily identifiable by its distinctive head crest, the toads only breed during cyclonic events, like a hurricane, when major low-pressures systems are present. Brookfield Zoo’s animal care staff created breeding habitats behind the scenes at the Living Coast building to mimic their natural environment, featuring a man-made system that allows for a simulated heavy rain to occur. For several weeks, the temperature in the toads’ habitat is dropped and then raised again over the course of a week to help hormones develop. Female crested toads then lay eggs that appear in long strands, which tadpoles hatch from within a couple of days.

The tadpoles from Brookfield Zoo are being released in Río Encantado, Ciales, located in the central mountain range of Puerto Rico. The species primarily faces threats from rising sea levels, habitat alteration, fragmentation, and the introduction of invasive species in the area.

In Puerto Rico, the tadpoles are acclimated in man-made ponds where they are monitored by the PRDNER, USFWS, and private NGOs until they metamorphose and disperse. Currently, there are six reintroduction sites located in historical habitat and separated from the last remaining wild population in the south.  The toads are generally only observed when they congregate during large rain events for breeding, as the species is difficult to monitor due to its fossorial, or burrowing, lifestyle.

#      #      #
Photo Captions (credit Jim Schulz/CZS-Brookfield Zoo)
0685: Thousands of Puerto Rican crested toad tadpoles that recently hatched at Brookfield Zoo were sent to Puerto Rico to be released to the wild as part of a conservation program to repopulate the species in its native habitat. The Puerto Rican crested toad, which is an endangered species, is the only toad native to the country.
0713: One of several animal care specialists at Brookfield Zoo, painstakingly counts each Puerto Rican crested toad tadpole prior to shipping them to Puerto Rico, where they are being released to the wild as part of a conservation program to repopulate the species in its native habitat.
3230: Just over 8,200 Puerto Rican crested toad tadpoles that hatched at Brookfield Zoo were sent to Puerto Rico for release to the wild. Each container had approximately 400 individual tadpoles.
3285 and 3294: Puerto Rican crested toad tadpoles recently hatched at Brookfield Zoo and were sent to Puerto Rico for release to the wild as part of a conservation program to help repopulate the endangered species to its native habitat.

About the Chicago Zoological Society
The mission of the Chicago Zoological Society is to inspire conservation leadership by engaging people and communities with wildlife and nature. The Chicago Zoological Society is a private nonprofit organization that operates Brookfield Zoo on land owned by the Forest Preserves of Cook County. The Society is known throughout the world for its international role in animal population management and wildlife conservation. Its Center for the Science of Animal Care and Welfare is at the forefront of animal care that strives to discover and implement innovative approaches to zoo animal management. Brookfield Zoo is the first zoo in the world to be awarded the Humane Certified™ certification mark for the care and welfare of its animals, meeting American Humane Association’s rigorous certification standards. The zoo is located at 8400 31st Street in Brookfield, Illinois, between the Stevenson (I-55) and Eisenhower (I-290) expressways and also is accessible via the Tri-State Tollway (I-294), Metra commuter line, and CTA and PACE bus service. For further information, visit


Sondra Katzen
Director of Public Relations
Office: 708-688-8351
Cell Phone: 708-903-2071


Center for the Science of Animal Welfare

Read about our innovative practices in animal welfare to ensure the ultimate care of our individual animals.

Classes and Camps

Center for Conservation Leadership

We place a high priority on developing and supporting conservation leaders of all ages and backgrounds.


Visit Brookfield Zoo

Create extraordinary connections with animals and nature!

Animal Welfare

You Can Help!

Become our partner in caring for animals and in connecting people with wildlife and nature.