Week Four

This week I've been thinking a lot about my dog and the way he smells things. Anytime I take him on a walk, he buries his nose in the ground. He loves smelling things. I wonder why? Why is smelling so satisfying for him?
I have also noticed that he can track objects by smell very adeptly. I throw a tennis ball into thick weeds in the back half of my yard, and he smells around for it until he finds it. He uses his sight to find it, but I can tell he definitely relies on his nose more than any other sense.
I looked up "dogs" on Wikipedia and found this statement: "Dogs have nearly 220 million smell-sensitive cells over an area about the size of a pocket handkerchief (compared to 5 million over an area the size of a postage stamp for humans)." This tells me that a dog's sense of smell is incredibly stronger than a human's. This, at least, helps me understand how important this feature is to this animal. I think , in general, creatures rely on and use those sense that are strongest. I think this is called a featural-advantage.
I wasn't sure if dogs have any kind of satisfaction from smelling. This article said that no evidence has been found to prove this. It did say that dogs do smell two kinds of things: permanent smells and temporary smells.