Why do dogs leap at the opportunity to stick their heads out of car windows while riding? Megan Schmidt of Discover magazine runs through several possible motives. The first is that dogs' sense of smell is so strong that sniffing all of that passing air is a exhilarating sensation to them:
The canine olfactory system is highly developed and far superior to ours. For starters, a dog’s nose is equipped with a complex maze of 300 million scent receptors, compared to our measly 5 million. The more receptors, the more sensitive the nose is.
And dog noses aren’t just cute — they’re practically designed to savor smells. Dogs have two air passages, one for breathing and one dedicated to smelling. To top things off, the canine olfactory cortex, the part of the brain responsible for processing smells, is 40 times larger than that of a human.
“When sticking their head out the window, they can smell every person in the street, every trash can they go by, every patch of grass, restaurant and other dogs. It’s like watching TV for us,” says Jennifer Cattet, an animal behavior researcher and owner of Medical Mutts, a service dog training center in Indianapolis.
Additionally, dogs may enjoy the passing sights, the air blowing on their faces, and the opportunity to contemplate escape.