Do Dogs Have a "Stinky Face" Too? Understanding the Canine Flehmen Response

If you’re a cat owner, you’re probably familiar with the hilarious "gaping mouth" look cats get after sniffing something pungent. But have you ever wondered if dogs do the same thing?

The short answer is: Yes, but it looks a lot different!

The Subtle Art of the Canine Sniff

While cats look like they’ve just witnessed a crime when they use their vomeronasal organ (Jacobson’s organ), dogs are a bit more active about it. Instead of a frozen, half-open mouth, keep an eye out for these specific behaviors:

• Teeth Chattering: Have you ever seen your dog sniff a patch of grass and then start rapidly clicking their teeth together? That’s not because they’re cold! They are physically pumping scent molecules toward the roof of their mouth.

• The "Tongue Flick": Dogs will often lick the air or a specific spot repeatedly. They are essentially "grabbing" scent particles with their tongue and pressing them against the Jacobson’s organ.

• Excessive Drooling: Sometimes, a scent is so "information-heavy" (like pheromones from another dog) that it triggers an overproduction of saliva.
  

Why Is It Less Obvious Than in Cats?

It comes down to hardware. A dog’s primary olfactory system (their nose) is so incredibly powerful that they don't always need to rely on the "mouth-smelling" method.

Cats use the Flehmen response as a primary tool for social communication. For dogs, it’s like an "Advanced Search" feature—they only trigger the teeth-chattering or jaw-popping when they find a scent that requires a deep, chemical deep-dive.

A Sight to See in the Wild

This behavior is common across many species. If you find yourself in the snowy fields of Hokkaido next winter, keep your binoculars ready! You might see a Red Fox (Kita-kitsune) or a Hokkaido Deer (Ezo-shika) performing a classic Flehmen response. In larger animals like deer or horses, the upper lip curls back dramatically, making it look like they are laughing at a private joke.

The Takeaway

Next time your dog sniffs something and starts chattering their teeth, don't worry—they aren't broken! They are just processing "Bio-Data" at a level we humans can't even imagine.