Biologic evolution

When a dog met a person, it is good to smell the person. The dog can lick the hand of the person, but, It is past to have been rubbed a hand against the tooth of the dog, and there is it three times. While the dog moves taste afterwards That check taste; more, I felt like confirming a smell. I do not smell it with a nose and smell it from a mouth. While the human being smells the food while eating, I enjoy taste. I do not think that it is impossible to smell from the mouth which was a dog. I think not only the dog but also the fish whether I am so.