Red-legged frog returns to Yosemite after 50-year absence

About fifty years ago, the red-legged frog disappeared from Yosemite National Park, due in part to habitat loss, invasive American bullfrogs, and an increase in raccoons. Park staff removed the bullfrogs and restored wetlands and riverbanks. In 2016, a breeding program began at the San Francisco Zoo, where frogs are raised from wild-collected eggs until they reach one to two...