In a single breeding cycle, Brookfield Zoo Chicago raised 12,244 Puerto Rican crested toad tadpoles—a record for the institution and a quiet triumph for one of Earth's most imperiled amphibians. The tiny, golden-eyed tadpoles, now released into the wilds of Puerto Rico, represent something far larger than a number: they are proof that a species brought back from the edge of extinction can keep climbing back.
The Puerto Rican crested toad holds an unusual distinction—it is the only toad native to Puerto Rico, and it was once believed to be gone from the wild entirely. For decades, a coalition of zoos, conservation groups, and government agencies has worked to change that story. Brookfield Zoo Chicago has been part of that effort for years, but this year's count stands apart. "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's lead animal care specialist. "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 process is anything but simple. Each year, breeding is carefully timed to coincide with Puerto Rico's rainy season, when conditions give tadpoles the best shot at survival. Animal care teams coordinate breeding pairs to maintain genetic diversity, then recreate seasonal environmental cues to trigger natural behaviors. Once tadpoles are counted—individually, by hand—and transported to the island, they are placed in managed aquatic habitats and monitored through metamorphosis before they disperse into the broader landscape.
Two Brookfield Zoo Chicago specialists traveled to Puerto Rico last fall to take part in that fieldwork firsthand. For a week, they monitored toads alongside partners from the Puerto Rican Crested Toad Conservancy, the Puerto Rico Department of Natural and Environmental Resources, and the U.S. Fish and Wildlife Service, tracking habitat use, predator pressures, and survival conditions. The collaboration is part of a broader network of 16 accredited zoos and aquariums working toward a single goal.
Over the past decade, Brookfield Zoo Chicago has contributed nearly 40,000 tadpoles to island-wide recovery efforts. The species remains listed as endangered by the IUCN, threatened by habitat loss, invasive species, rising sea levels, and saltwater intrusion into the freshwater wetlands where they breed. The last known wild population clings to existence in the Guánica Commonwealth Forest in southwestern Puerto Rico.
Yet there are reasons for cautious optimism. Earlier this year, two Puerto Rican crested toads went on display in the Zoo's Swamp habitat, giving visitors a rare glimpse of a species most people had only encountered on album covers. Millions were introduced to these toads through Bad Bunny's Grammy-winning album "DeBí Tirar Más Fotos," a surreal turn for a creature that spent years thought lost to the world. Brookfield Zoo Chicago now cares for roughly 20 individuals, most housed behind the scenes as part of the living archive that keeps the species alive.
Twelve thousand tadpoles is a number. But each one represents a second chance—and a species that, against the odds, is still fighting for tomorrow.