06/30/2019
So this raises questions. As you may recall, studies into calming signals have not shown that these signals alter other dogs’ behavior - or “calm” them. Could lip licking be either a response to a drying nose during stressful situations (changes in stress chemicals causing the nose to dry) OR during social interactions is it best to have a wet nose to gather smells?
Hmmm...
The philtrum is the vertical groove between the base of the nose and the border of a dog's upper lip, and it has a purpose. Every time a dog licks his lips, a bit of saliva stays in this groove and is drawn upwards due to capillary action. This keeps the dog's nose moist, if not wet, which enables the dog to capture scent particles from the air. Pretty cool, eh?
Image from Wikicommons