A dog headed to the park or on a roadtrip with its head stuck out of a car window is the perfect picture of happiness. But why is it that dogs love sticking their head out the window so much?

Most scientists and dog experts believe that it has to do with their excellent sense of smell. Dogs rely far more on smell than they do on any other sense, so the air rushing past them and into their nose represents an all-you-can-eat buffet of information about the world around them.

If you have a fun picture of a dog enjoying a car ride with its head stuck out the window, please add it to this list!