Dogs love the wind don't they? Although we should not allow it; dogs love to hang their heads out the car window taking in all the scents that they can. It is dangerous to do this because they could get something lodged in their eye, hurt their throat or all sorts of things. Anytime the breeze comes up my dogs all face the wind and let their ears flap. They love it; it is a transportation device for smells.
The other day Luke was standing out at the top of the yard, ears flying in the wind, eyes squinted and nose working overtime. He was catching the scent; who knows what he was getting in it but he was definitely enjoying himself. Dogs have the ability to smell some 100,000 times better than we do. Hard to wrap your head around that number eh? Watching them follow a scent is very interesting and if you watch closely you will see them use their sense of smell often.
Many times my own dogs loose sight of someone they have been following; say my husband or myself. They immediately drop their head to the ground and start the scenting process of finding that person. They know the difference between a fresh and old scent and can follow the most recent one. This is very clear when Jessie (my Jack Russell) is hunting for critters. She sticks her head into each hole in the ground but only digs the holes where there is someone home presently. No doubt all of the holes smell like critters but she knows which ones have tenants who are home.
As dogs age they tend to loose some of their scent ability. One reason why I now can find food on the floor in the kitchen, not only has Jessie not seen it she has not smelled it either. Click on this article on a dogs sense of smell for a great read.