Los Angeles once had a four-legged folk hero: P-22, a lone mountain lion that improbably took up residence in Griffith Park. But this particular effort comes with a breathtaking price tag and lavish overengineering—and is entirely unnecessary to protect the mountain lion. The bridge's proponents insist it's needed to address low genetic diversity in the Santa Monica Mountains' mountain lion population. The 101 freeway limits animal movement between the Santa Ana Mountains and the Santa Monica Mountains. Bridge proponents see the Santa Monica Mountains' mountain lions as a population on the brink.