Horizon: The Secret Life of the Dog

The series that explores topical scientific issues looks at the increasing research into dogs that is giving scientists a greater understanding of humans themselves. A breeding experiment in Siberia reveals how dogs evolved from wolves, Swedish scientists demonstrate how the human/dog bond is controlled by a powerful hormone also responsible for bonding mothers to their babies, and Horizon meets Betsy, reputedly the world's most intelligent dog, and compares her incredible abilities to those of children. episode 8