Dogs have been domesticated for longer than any other animal on the planet and humans have developed a unique relationship with these furry friends. We treat our pets like a part of the family and we feel that they can understand us in a way other animals cannot. Now, new research is revealing what dog lovers have suspected all along: dogs have an uncanny ability to read and respond to human emotions. What is surprising, however, is new research showing that humans, in turn, respond to dogs with the same hormone responsible for bonding mothers to their babies. How did this incredible relationship between humans and dogs come to be? And how can dogs, so closely related to fearsome wild wolves, behave so differently? It's all in the genes. "Dogs Decoded" investigates new discoveries in genetics that are illuminating the origin of dogs -- with revealing implications for the evolution of human culture as well. NOVA also travels to Siberia, where the mystery of dogs' domestication is being repeated -- in foxes. A 50-year-old breeding program is creating an entirely new kind of creature, a tame fox with some surprising similarities to man's best friend. This film reveals the science behind the remarkable bond between humans and their dogs and spurs new questions about what this could mean for our relationships with other animal species.