One of the topics addressed in this series (3 discs in the version I viewed) is the origin of both species. The segment on the origin on cats was a bit confusing - first asserting they originated in Turkey, then Egypt. In either case, cats were persecuted unmercifully during the Middle Ages, to mankind's enormous detriment. The rat population soared, and about 25 million died in the Bubonic Plague. The program also tells us that cats adopted man, and maintain a bit of wildness to this day.
Dogs, we learn, have the greatest variation of any mammal. About 80% of all breeds were not available 130 years ago; all dog breeds share 99.8% of their genes. Specialty breeds have the least variation and about 25% suffer from inbreeding. Curing those problems and others (eg. cancer) within dogs may bring hope for humans as well. The first evidence of breeding appears about 5,000 years ago in Egypt. Humans can see better than dogs, cats hear better than dogs, but dogs have the best sense of smell.