The average dog is as intelligent as a two-year-old child. The Beatles song A Day in the Life has an extra high-pitched whistle, audible only to dogs. It was recorded by Paul McCartney for the enjoyment of his Shetland sheepdog. In ancient China, an emperor’s last line of defense was a small Pekingese dog hidden up his sleeve. Dogs only sweat through the pads of their feet. The most popular breed of dog in the world is the Labrador.