Why do dogs put their heads out of the car window?
Dogs literally love to put their heads out the window because they can smell a myriad of new smells coming from all directions.
The nose of dogs is not remotely comparable to that of humans. We have 5 olfactory receptors, dogs have up to 250,000 million scent glands. So it is really impossible for us to be able to understand the amount of smells that our four-legged friends feel.