Instinct (1999)

Human drama - Anthropologist (Anthony Hopkins) studies and lives with gorillas for years in the jungles of Africa. When hunters track and kill members of the gorilla family, the man retaliates with vengeance, killing several hunters. Imprisoned and then declared insane for violence and refusing to speak, he loses his human family and all chances of return to normal life. Enter psychiatrist (Cuba Gooding Jr) who struggles to get inside the doctor's head hoping to eventually free him. Great story and with over the top acting. Just over 2 hours.