The next time you’re in your dog’s mouth (you do brush his or her teeth, right?) notice the bump on the roof of his mouth just  behind the two front middle teeth? It’s called the ‘incisive papilla,” and near the center of it is a hole that leads to a duct that leads to the “Jacobson’s organ.” The Jacobson’s organ is a very cool thing. Put in “See Spot Run” terms,  it allows your dog to literally taste the air by combining taste and smell.

Dogs use their Jacobson’s organ to experience sexual markers (pheromones) left behind by other dogs via urine,  or when coming across the scent of a bitch in season. While dogs don’t have a Flehmen response seen in many other animals (throwing  back the head, and raising or curling the upper lip which helps open the entry slits into Jacobson’s Organ), dogs will “chatter their teeth” instead.  A dog might hold his mouth in a quasi-open position that looks a little like a grin, or he might even lick the air.  And you thought he was just happy to see you.

One theory holds that the Jacobson’s Organ could account for a dog’s ability to identify and recognize other animals and people. It’s also believed that it’s this organ that enhances a newborn’s ability to find its mother.

Image found on Pinterest (without the arrow) and happily credited upon receipt of information