Oakland Zoo Releases 1,000th Frog as Part of Critical Effort to Combat Deadly Disease

Oakland, CA – August 7, 2025 On Tuesday, Oakland Zoo transported 43 yellow-legged frogs by helicopter to their release site in Sequoia and Kings Canyon National Park . This release marks the 1000th frogs released by Oakland Zoo and a decade of efforts to save these frogs, now on the verge of extinction from a deadly disease, Chytridiomycosis (chytrid). This release was in partnership with Mountain Lakes Research Group, the U.S Fish and Wildlife Service, and the National Park Service.

Yellow-legged frogs have experienced a 90 percent decline in their population due to the devastating effects of the chytrid fungus, a global pandemic considered the most significant loss of biodiversity caused by a pathogen. Oakland Zoo emphasizes the importance of saving frogs because they play a crucial role in the ecological food web as prey for larger animals and as predators of insects that control populations. They have permeable skin making them easily affected by environmental changes. This trait makes them excellent bioindicators, alerting us to environmental stressors. Frogs once were a keystone species in high elevation lakes but chytrid and other factors reduced their populations significantly.

“Releasing our 1000th mountain yellow-legged frog is a major milestone. It's a number that you hope to achieve when you start a program. This milestone has been reached because of the numerous dedicated staff members and volunteers who have been involved with this program over the years. We need to keep this movement going to continue helping native California wildlife and make sure that these frogs don't disappear,” says Samantha Sammons, Wildlife Recovery Program Manager at Oakland Zoo.

The Zoo collected these frogs as tadpoles in 2023 and raised them through their life cycle to be released back into the wild. Oakland Zoo's frog recovery program, for the three species of yellow-legged frog (Mountain, Sierra Nevada, and Foothill), involves extensive efforts before the frogs are ready for release into the wild. The process starts with tadpoles collected from nature and brought to the Zoo, where they are carefully cared for in an optimal environment to complete their life cycle. During the 'froglet' stage, they undergo anti-fungal chytrid treatments to protect against the virus once reintroduced to the wild. After treatment, they are pit-tagged (similar to microchipping pets) for monitoring, then receive their final inoculations. They are swabbed once more for chytrid, and if clear, prepared for transport to their release site.

Earlier this year, the Zoo launched its Conservation Strategic Plan that aims to formalize its efforts in wildlife conservation for the next three years. By defining a clear scope, the Zoo can effectively organize its resources and energy to make a difference. With decades of conservation experience, the Zoo is uniquely positioned to take action for ten key species that need human intervention to thrive – including this native yellow-legged frog.

As part of the yellow-legged frog recovery program, Oakland Zoo is beginning to expand its efforts to save these species through genetic rescue—also called biobanking frog genetics—and by developing methods to propagate the species for future release.

ABOUT OAKLAND ZOO AND THE CONSERVATION SOCIETY OF CALIFORNIA:

Oakland Zoo envisions a flourishing planet where people and wildlife thrive together. The Zoo’s mission is to deepen connections with animals, save wildlife, and inspire champions for the natural world. Oakland Zoo is an accredited Association of Zoos & Aquariums member, managed by the Conservation Society of California, a non-profit organization.

###

‍