The Second Sense Of Smell

[sandgrubber]

In general reading about scent detection I've come across descriptions of a secondary olfactory organ, called the Jacobson's organ or vomeronasas organ. (Google the term for more description). Human noses only detect vapor phase scents from the air. This other organ works on liquid phase compounds. It's present in many mammals, as well as snakes and some other animals, but largely absent in humans. Most of the scientific research on this organ focuses on the sex lives of mice...pheromones, oesterus, and what not. Seems to me it may explain why dogs take such joy sticking their noses into odd and disgusting things; and why so often they seem to respond to things we cant sense. Putting your nose directly into a pile of something and snuffeling around a bit may be the olfactory equivalent of a magnifying glass. In my experience lots of biologists are fixated on sex, so it's to be expected that much attention has been given to the use of this organ in detecting pheromones, etc. But I often see dogs taking great pleasure in using their noses. Sticking them down a hole or into a pile of leaves ... And many many times I've found one of my dogs sleeping with its nose pointed directly to one of my smelly socks or some other item of clothing that has gotten fragrant through wearing...as though they get comfort from the body odor.Just curious . . . .has anyone seen anything good written in the dog behaviour literature that does a good job discussing what this sixth sense does for dogs?

Edited February 9, 2013 by sandgrubber

[Greytmate]

No. This is the only place I've read about it. I see a distinct difference in the way some male greyhounds sniff different things. When they sniff the source of the pheromone, they start drooling and tasting the smell and rolling it around on their tongue and smacking their lips. Their facial expression says "ooh, so piquant! " My facial expression says "you're gross dog."

[moosmum]

Maybe not as in depth as you are after,but " Inside Of A Dog" (Alexander Horowitz)

is a good read, giving the reader insight to how a dog experiences the world.

[espinay2]

Phlemen. Dogs aren't the only species that do this. Horses too for example. May will have seen when they lift their head and stick their lip up. Using the jacobsens organ by eliciting a phlemen response is not the same as sniffing things. It is really not much to do with the nose. Closest thing for humans is tasting with the palate.

[Kirislin]

Phlemen. Dogs aren't the only species that do this. Horses too for example. May will have seen when they lift their head and stick their lip up. Using the jacobsens organ by eliciting a phlemen response is not the same as sniffing things. It is really not much to do with the nose. Closest thing for humans is tasting with the palate.

I wonder if it's like when I lift the rubbish bin lid to drop a poo bag in there but forget to hold my breath. If I happen to be breathing in at the time I taste all the disgusting stuff that's already in the bin.

[Showpony]

Phlemen. Dogs aren't the only species that do this. Horses too for example. May will have seen when they lift their head and stick their lip up. Using the jacobsens organ by eliciting a phlemen response is not the same as sniffing things. It is really not much to do with the nose. Closest thing for humans is tasting with the palate.

I wonder if it's like when I lift the rubbish bin lid to drop a poo bag in there but forget to hold my breath. If I happen to be breathing in at the time I taste all the disgusting stuff that's already in the bin.

Hi,

Learn something new everyday.....this is interesting......having Pointers who are a scent breed, I often watch them hunting and sniffing, they will sniff the ground but the bred evolved to be air scenters when on the move......but what has always given me a good giggle, is there are some that say, the reason that a Pointer has a dish face is this is to hold the scent......I find this very strange as this would put the scent ontop of the muzzle and in front of the eyes.......I have run this by a few tracking friends who basically ROFL, and I was told that scent has to be in the nose, hence why Pointers have large, open noses....LOL....it's so funny how ppl get so set in their opinion

[Poodle Mum]

Cats do this all the time!!! We call it "the stinky cat face" here!! They have a large Jacobsen organ. It is very similar to when a human does the whole "wine tasting time"....swirling it the mouth with air & making the gross slurping sound!!.....Me....I just swallow it :D

If you want to see another good example....entire male dogs when sniffing at bitches or their urine , often teeth chatter as well as drooling & slobbering!

[m-j]

Not sure if this book has exactly what you are after in it but the best book I have read regarding dogs scenting abilities and scent is called Scent and the Scenting Dog by William G Syrotuck.

[sandgrubber]

Found a good description of the whole scent system on the web.http://www.whole-dog-journal.com/issues/7_11/features/Canine-Sense-of-Smell_15668-1.html

Extracted from that article...but I'd recommend reading the whole article. It contains amazing figures comparing dog to human olfactory systems. Elsewhere the author says the vomeronasal system works synergistically with the other smell system. The result is something we humans can hardly imagine.

"Jacobson's Organ Inside the nasal cavity and opening into the upper part of the mouth is the final piece of the dog's scent-related puzzle, the remarkable Jacobson's Organ. Jacobson's Organ is a "sense of smell" receptor that is actually not receptive to ordinary odors. Rather, the scenting nerve cells of the organ are quite different from those in normal olfactory tissue in that they respond to a range of substances that have large molecules, but often no detectable odor.

The sensory cells of Jacobson's Organ (which anatomists claim are unlike any other nerve cells) communicate not with the olfactory bulbs and cortex, but with the accessory bulbs and the part of the brain that coordinates mating and other basic emotions. In fact, recent evidence suggests that the two separate but parallel systems of odor detection cooperate in surprising ways to produce novel sensibilities not achievable by either of them on their own."

[sandgrubber]

Learn something new everyday.....this is interesting......having Pointers who are a scent breed, I often watch them hunting and sniffing, they will sniff the ground but the bred evolved to be air scenters when on the move......but what has always given me a good giggle, is there are some that say, the reason that a Pointer has a dish face is this is to hold the scent......I find this very strange as this would put the scent ontop of the muzzle and in front of the eyes.......I have run this by a few tracking friends who basically ROFL, and I was told that scent has to be in the nose, hence why Pointers have large, open noses....LOL....it's so funny how ppl get so set in their opinion

The sniffling behaviour comes from blowing with the nose to "lift" the scent molecules ... ie get them into aerosol form to allow the vomeronasal organ to process them...and then inhaling the lifted scent.

[Inka3095]

This thread is very interesting :)