In the early 1800s a Danish chap Ludwig Jacobsen discovered an organ in the roof of the mouth, in the nasal cavity that's specifically to do with olfaction – which is a weird sounding word that means the sense of smell. Humans have this too, but evolution has determined we don't need it, so it doesn't function as it used to – like your tail bone or appendix. The Flehmen Response is more obvious in some species who have this working vomeronasal organ, or more easily pronounced Jacobsen Organ. For example horses. When their lips are up, teeth bared, air is sucked in to the mouth where it enters a duct taking it to the Jacobsen Organ. Dogs Flehmen Response is less obvious but you've probably seen it especially around urine deposits – it's the tongue flick, smack in to mouth or puffy lips. This is because the vomeronasal organ detects pheromones; chemicals for social and sexual communication.
And you thought they were just grossly close to something invisible.
Who knows what the perfect doggy handshake looks like? Hopefully you all said face to bum with curved soft body language. When dogs sniff each others rear end they are gathering information about the age, sex, health and even diet of the sniffee.
Sniffing isn't only for chemical communication. It can be used as an attempt at physical communication by way of mini breaks as a calming or appeasing body language signaling “dude chill out, I need a minute.”
If you are interacting with, observing or training a dog and they walk off to sniff, it could be that there's a much more interesting smell nearby. It's also quite possible that they are uncomfortable in that situation and are using sniffing to deflect attention.
If it's too hot and they're panting to cool down, they can't sniff. Panting is also a sign of anxiety/stress building. Imagine you're uncomfortable and the thing that can calm you is not an option. Check out the picture below, taken from https://www.frontiersin.org/articles/10.3389/fvets.2018.00056/full
Part three up next, thanks for reading!
