We've all seen people driving along with their dog's head hanging out the window. It's obviously a very entertaining event for the hound, but could this also cause harm to the pup? After all, a dog's sense of smell is a lot more developed than ours. And at forty miles per hour, dogs get more of a nose-full than they can walking around the block.
Compared to the measly five million aroma receptors embedded in human nasal tissue, which is about the size of postage stamp, some dogs have over 200 million receptors that are embedded in a sheet of tissue that, when unfolded, would be big enough to cover one-third of the dog's surface area.
Not only that, but at the back of each dog's mouth is a special organ that seems to give dogs the ability to distinguish between different odors. Also, the part of the canine brain that processes data from the nose is enlarged, especially in breeds trained to hunt with their noses.
As pleasurable as it might be, Don, allowing Fido to stick his head out of the car is dangerous. A bug in the eye at 55 miles per hour can do a lot of damage. It'll be to everyone's advantage if Fido just enjoys the view, and gives his sniffer a rest.