The nose of a dog is marvelous in its smell. Humans possess an average of 5 million scent receptors located in the nose by contrast dogs have up to 300 million, although this may vary with the breed.

Humans are often embarrassed when a dog trots over and starts sniffing at their groin, or pokes its snout in their butt. The dog has no idea that placing its nose in these parts of the human body ...