Ever noticed those slits at the sides of a dog’s nose? Why do dogs have them?

Once again, nature proves her elegance in the design of our dogs. When we humans inhale and exhale, air comes in the same way it goes out. Any smells that come in through our mouths are forced out as we exhale.

When a dog exhales through his nose, however, the exhaled air is released through those slits and off to the side so that nice, smelly air going into the dog’s nostrils doesn’t get diluted with the outgoing air. Put another way, the slits allow the dog to avoid smelling what he just exhaled.

The slits help the dog hold scent particles in the nostrils even as exhaled air passing out the slits creates a swirling air turbulence allowing interesting odors to be inhaled directly into the centre of each nostril.  Since dogs breathe faster when trying to sniff a certain smell,  they widen their nostrils to pull in more air which makes it possible for a dog searching for smells to have a steady stream of air coming in for up to 40 seconds, maybe even longer.

The slits also allow dogs to wiggle each nostril independently which gives them the ability to know which nostril a smell entered. This is how a dog can pinpoint where a smell is coming from, and why a dog searching for smells on the ground will weave back and forth as he follows a trail.

We all know the superb smelling abilities of dogs, but let’s use an analogy between scent and sight to really put it into perspective:  What we as humans can see at a third of a mile, our dog can see more than 3,000 miles away and still see as well.