In the early hours of a Friday morning, a mountain lion moved through the crowded Sunset District of San Francisco — a reminder that the boundary between wilderness and city is more porous than we often choose to believe. Wildlife officials, police, and zoo staff converged in a rare collaboration to tranquilize and safely relocate the animal, fitting it with a tracking collar before returning it to the wild. The encounter, one of at least two mountain lion sightings in the city this month, raises quiet questions about how human settlements and apex predators are learning — or failing — to shar