Steve Winter is famous for his photographs of big cats in their natural habitats, such as snow leopards and tigers, among others. His “Ghost Cats” story in the December 2013 issue of National Geographic opens with a surprising image of a big cat, not in the wilds of India, but in a location arguably as challenging for photographing his subject—downtown Los Angeles.

Winter’s task was to illustrate cougars—also known as mountain lions—in an urban environment. His research led him to biologist Jeff Sikich, whose work with a mountain lion population in the Santa Monica Mountains National Recreation Area on the outskirts of L.A. seemed promising. “Science-wise, this guy really knew what he was doing,” says Winter.

Winter knew that if