The other analogy he shared was that of entering a flower shop. Humans walk in and are overwhelmed by sweetness, a combination of all the flowers there. As we decide to buy one kind, such as roses, we hold it up to our nose to focus on that one flower. A dog would smell each of the flowers individually, as well as leaves, plastic basins, wood of the door, linoleum, the shop owner's clothes... and everything else that is present. If searching for one particular odor, dogs can focus and separate that one out of the potpourri.
This reminded me of something I had learned about watching/listening to an orchestra or band with singers. As humans, we mostly listen to the music and voices as a whole. What some people don't realize, is that if you focus your visual attention on one singer or one instrument, you will hear that singer or instrument over the rest of the performers. Likewise most people can pick one voice out of a melange of voices and background noise to listen to that person (this ability is lost with hearing aids).
Everything gives off molecules and in order for that thing to be smelled, the molecules must make it to the nose. Molecules come in three types:
- lightweight - move in the air
- volatile - evaporate easily
- soluble - broken down by moisture
As I mentioned yesterday, dogs process air in two ways, directly through the olfactory structures for scenting or in a curved path for simple breathing. Dogs actually have the ability to re-process air through the olfactory structures! Dogs often sniff more forcefully when they are focusing to find an odor and you can sometimes hear the difference. There are times that I can really hear Gimme make a huffing noise as she is searching, which sounds like a tiny cough to me.
Fred told us that scent memory is the strongest memory of all for dogs. This likely explains why imprinting a scent associated with feelings of calm and safety is so powerful. Gimme and I both sleep on large flat sachets of lavender, so I'll have that available as a scent cue for her to feel calm and safe in challenging environments. I asked about the practice of some handlers to re-scent a dog while tracking and he believes its completely unnecessary.
He also cautioned against the practice of some trainers to whack their dogs across the nose with the leash or cuff them on the side of the head by hand. The olfactory structures are located in the top part of the nose and any blows can damage those structures.
We watched a LOT of videos of dogs doing scent work (mostly from his time as a police canine trainer). Fred told us to watch the dogs' mouth and note when it is open and when it is closed. A dog with an open mouth is still taking in some scent information through the vomeronasal organ, but when they sense a smell that interests them, they will close the mouth (or partially close it) and start using the nose. Some of the videos were shown at regular speed and again at half speed. Once I understood about the importance of whether the mouth was open or closed, It was fascinating to see it in action.
In tracking and nosework, we are mostly behind our dogs and not able to really see this. One advantage to nosework is that we can move alongside or around the dog to take advantage of seeing the working end more clearly. This is an obvious clue as to when a dog is scanning versus when they've started detailing.
Our dogs are looking for a scent picture... that is "the combination of odors which are present that a detector dog identifies as a trained odor." He touched on the importance of making sure that we use many different types of odor containers in training, so we don't unintentionally teach our dogs that they are searching for birch+plastic or anise+tin. We need to vary the container so the dog understands its birch, anise or clove that is the odor picture they are looking for.
More to come...
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