Please note that while Yosemite remains open during the federal government shutdown, services and facilities are very limited, and certain areas of the park are closed. For more information, please refer to the National Park Service and the Department of the Interior: visit and

As the impact of the government shutdown continues to be felt, Yosemite Conservancy remains committed to supporting Yosemite National Park.

Click here for more information on the availability of Yosemite Conservancy programs and services during the shutdown.

Yosemite Valley Predators: Raccoons, Ravens and River Otters – 2017

Yosemite Valley Predators: Raccoons, Ravens and River Otters – 2017

Yosemite scientists survey Valley predators to protect endangered species. Photo: Rick Kimble.

Thanks to Conservancy donors, aquatic ecologists are restoring two rare species in Yosemite Valley: the western pond turtle and the California red-legged frog. As scientists release frogs and turtles along the Merced River, they are bringing back animals whose populations in the park have declined precipitously or vanished altogether.

In 2017, scientists focused on fine-tuning the reintroduction process by studying species that prey on amphibians and reptiles. They used remote cameras, tracking collars, scat samples, and staff and visitor observations to map the distribution and abundance of key hunters. Their research revealed fascinating findings, including documentation of raccoons ascending high above the Valley floor, and the detection of elusive river otters at four sites along the Merced River. In addition to using the data to identify optimal sites for future frog and turtle releases, scientists can draw on the findings to improve food storage and waste disposal in areas frequented by raccoons and other species that forage in human trash.

Your support helped scientists study Yosemite Valley predators in order to give vulnerable frogs and turtles the best chance at survival.

Completed in partnership with Yosemite National Park and University of California, Davis.

More Scientific Research Projects

Project Notes
Yosemite scientists survey Valley predators, like this raccoon, to help ensure the success of endangered species recovery. Photo by David Grimes

The NPS has a mandate to preserve and protect its wildlife, and biologists in Yosemite are working hard to not only protect current species, but also to restore lost ones. Mapping predators helps us protect endangered species.

Rachel Mazur
Wildlife Biologist
Yosemite National Park