A Dog’s Nose Always Knows (Encore)

What in the world is a dog's secret sniffing power? How in the world do their noses know more than ours? And why are we putting these noses to work? Join Guy Raz and Mindy Thomas as they explore latest Who, What, When, Where, Why, How, and Wow in the world of super sniffing canines! (originally aired December 25th)