Director James Marsh, who made the fascinating documentary Man on Wire, has topped himself. This documentary about Nim, a chimpanzee raised as a human child and taught sign language in the ’70s, is an absorbing viewing experience. The facts of Nim’s life are proof that animals should roam free in their natural habitats, because things go very badly for the once-famous chimp. Marsh pulls no punches in showing the human carelessness and bad decisions that take Nim from the false comforts of a middle-class home to a lab-experiment cage. Seeing what happens to Nim is heartbreaking, even if the final chapter of his life involved a quiet life free of lab experiments in a spacious cage full of toys. Nim had no business being in a series of psychological and physical experiments, and deserved a different destiny, a message March delivers in searing fashion.