Jake Gyllenhaal is running, hard. It is October 2013 and he is alone, at sunset, humping across the rugged hills of Los Angeles' Griffith Park, in a grueling 15-mile run to the set of his new movie, Nightcrawler. He does this every day. He has shed almost 30 pounds. He lives on kale salad and chewing gum. He has not seen his friends in weeks. As he runs, he recites lines—entire monologues—from the movie in his head like a mantra until he has the script memorized. ''I worked like a motherf---er,'' he says now. Each night, as he runs, he thinks about the creatures that shuffle out into the twilight. ''After mile 10, I'd have these strange fantasies of being one with the animals,'' he says. In particular, of being one with the coyotes. ''Growing up in L.A., you have these totally random interactions with coyotes. They're in my soul somewhere. They hold the power because they don't give a s---. They are hungry and they are out to get what they are going to get. It gave me this permission to become that.