The Science of Aged Hides in Small Rooms

As a part of my Nosework Challenges Series 1 class coming out in February, I’ve been working on a weeks worth of advanced aging lectures.  This is an excerpt from one of those lectures…

Aged hides in a small room give us a new challenge.  Odor permeates the room in every nook and cranny.  Small rooms are actually easier to run with less aging because the odor tends to stay close to source.  In a trial you could very well find yourself searching a hide that is possibly up to 6 hours old….  But let’s play with the aging window and really push the boundaries.  Of course with time, aging reaches a plateau and the search area is fully saturated with scent.  Essentially, the odor molecules in the air stabilize and you hit a maximum saturation.  This really depends on a number of factors including the vapor pressure of the oil you are using, the temperature and the ventilation in the search area.  (I wonder what my dad would think if he knew that I use my Chemical Engineering degree to apply it to dog training!  Somehow I can picture his facial expression…  part exasperation and part humor I’m sure!)

Let’s discuss Vapor Pressure…  I’m going to get a little technical so please bear with me…  hopefully I can make this plain English!  However I think it’s important to discuss because it gives us an idea how advanced aging works in a closed room, and how scent saturation occurs.

From Wikipedia:

“Vapor pressure or equilibrium vapor pressure is defined as the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases (solid or liquid) at a given temperature in a closed system. The equilibrium vapor pressure is an indication of a liquid's evaporation rate. It relates to the tendency of particles to escape from the liquid (or a solid). A substance with a high vapor pressure at normal temperatures is often referred to as volatile. The pressure exhibited by vapor present above a liquid surface is known as vapor pressure. As the temperature of a liquid increases, the kinetic energy of its molecules also increases. As the kinetic energy of the molecules increases, the number of molecules transitioning into a vapor also increases, thereby increasing the vapor pressure.”

Picture attribution: "Vapor pressure" by HellTchi - Own work. Licensed under CC BY-SA 3.0 via Commons -

So in plain English…  Oils are volatile…  our dogs are actually smelling the oil that has turned from liquid to gas.  Essential oils have a high vapor pressure.  That means that it takes a high air pressure to keep the oil from evaporating…  so when the temperatures are normal to higher, there will actually be more scent in the air because more of the oil has evaporated.  At normal air pressure, scent of these volatile substances evaporates and the dog can easily capture the scent.

When a door is closed, over time, the air fills with scent molecules and the system essentially stabilizes.  Of course the “system”…  meaning the room, never really seals, so scent will continue to evaporate from the Qtip.  However, because this process is continuous, the room essentially for all intents and purposes becomes saturated with scent.

Now picture this, you open the door and the dog has to search through a sea of scent.  There is really very little definition left to the scent cone so this makes the task rather challenging.  In competition, you will probably never search a fully saturated room, however you WILL encounter small spaces where the door has been closed and the hide has been aged.  Therefore, it makes sense to train for this scenario!

Here’s a graph of the relationship between vapor pressure and temperature…  this is water…  This is why it feels so humid when you are near the water in the heat!  This means that the hotter it is, the more pressure is required to keep the water in liquid form.

Picture attribution: ATMS 101 Summer 2003

What does this mean for small enclosed areas?  This means that the hotter the search temperatures are, the more scent will be in the air.

What about the time factor?  It takes time to reach saturation.

So what is saturation???  Saturation is when the number of particles in the air stabilizes versus the particles in liquid form (meaning the oil on the Qtip).  So with aging, we reach equilibrium at an unknown point of time.  Therefore, if we place a hide, close up a room and let it sit for a long, long time…  we have essentially created a very challenging puzzle for our dog.

Happy Sniffing!!

Elliptical Search Patterns and Fast Dogs

I’ve been fascinated lately with fast versus efficient dogs and natural search patterns.  From watching MANY videos and dogs I’ve seen a distinct difference in the searching approach between fast and efficient dogs.  I’ve seen a natural tendancy for elliptical search patterns with ALL dogs, but it’s especially obvious in naturally fast dogs.

I’m in the middle of authoring some content for my Nosework Challenges Series 1 class that debuts in February and this topic seems to crop up more and more in the material. 

Let’s talk about natural search patterns.  Natural search patterns are the paths that a dog will naturally take executing a search.  Let’s face it.  Dogs don’t think in terms of corners and thresholds.  Dogs think in terms of circles.  If you watch a dog herding or scenting / hunting in an open area, the dog will naturally take a very round path.  This is normal. Dogs don’t “do squares”.  So now we’ve taken these naturally elliptically thinking creatures and ask them to search mostly square search areas…  and then wonder why corners are so easily missed!

I’ve noticed that this elliptical tendency is greatest with fast dogs.  It’s almost as if there is a centrifugal force with these dogs keeping them on a circular path.  This pattern is most obvious with green dogs and very fast dogs.

Here’s an example of a wonderful working dog, Java, executing a search.  Java is a fast girl who is very enthusiastic for the game.  She’s still very green but shows tons of promise.  Watch her elliptical path before she settles into the search and finds source.  Her owner, one of my students, was kind enough to share the video with me.  You will see this tendancy with both searches on this video.

So the search pattern that we typically get is this:

In reality the search pattern that we really want is this:

Interestingly, I’ve seen more efficient dogs execute more closely to the path above.  The reason behind this is that efficient dogs are slower dogs.  Of course that’s not a bad thing at all!  Efficient dogs actually get into corners on the first pass because they aren’t as impacted by the centrifugal force of the search as fast dogs.

This is further evidence that neither fast nor efficient dogs are better!  They just search differently!

Fast dogs may in the end take a longer time to mature into truly excellent searching dogs simply because these dogs are fighting biology and natural tendancies…  the centrifugal force of searching behavior.  The result of course in NW3 is missed hides.  Handlers of these dogs…  Fear Not!  With experience and time, your dog will learn to get into those corners.  In the meantime when you are practising or trailing, make sure your dog covers these areas well. The key is in watching whether your dog has actively searched the area or just skimmed it.

Keep working those corners guys!

Fast vs. Efficient

The grass is always greener right?  One thing is for sure, the playing field is more level than people realize…  Fast Dogs vs. Efficient Dogs..  or rather why one is not better than the other..


Being a teacher is wonderful…  it’s wonderful beyond the relationships that you build with your students, the joy you have in their successes and the love of their dogs…  It’s by far the greatest learning experience there is.  Instructors over time learn to handle all breeds and breed types if only by proxy.  This enables us to be flexible in constructing challenges for each dog that stretches the team’s skills and pushes them along the way of success.  Along the way we might also hear comments such as “so and so earned Elite in X number of tries” or “well so and so runs a fast dog”…  And you know what?  It’s all irrelevant.  Of course in the end we all bring home the best dog in the world..  but beyond that, it really is irrelevant!  Why?  Because every type of dog has its advantages.

Let’s compare Fast Vs. Efficient…

Personally, my Elite dog is a fast dog.  He’s a total blast to run…  a real rush.  However, in as much as I love him with all of my heart, it doesn’t mean that he’s better than the next dog who might be slower.  That’s kind of hard for me to say because I feel in the heart of my hearts that he truly is the best creature ever to walk on this planet…  but of course I am biased!  From a skill perspective, he is strong.  I have always said that his only weakness is the lug at the end of his leash.  In reality though, yes he’s a strong dog but in his strength there are weaknesses.  He has never walked away from a trial without a placement or two of some sort but is that better than a slower dog?  No.

At the same time there are teams that I train who have what I call more efficient dogs.  These are dogs that visually seem to take their time.  In the end though, these teams may achieve their goals more quickly.  There is still a rush of adrenaline but in this case it’s in watching perfection…  the sheer lack of mistakes.  These dogs may not take home placements in the elements but they take home the title ribbons more often than not.  In the path to Elite, these teams tend to take fewer tries…  they simply make less mistakes.

So why is this?

I have a theory… It’s centered around the dog’s reaction to scent in relation to efficiency of his search path.  There are two types of dogs, Fast and Efficient.  Let’s discuss how they search.

Fast dogs will detect the strongest scent and follow it to source.  Along the way, he may come in contact with odor from other hides.  However, he will ignore these hides in favor for the one that is most enticing even if it means that there is much wasted motion in narrowing down the location of the hide.  During all of this, the handler may or may not have noticed interest in a location along the original path of the dog.  Yes, these dogs pass up hides and they pass them up often!  Depending on the speed of the dog it’s quite possible that the scent of a hide along the initial trajectory is more of an afterthought.  It takes a very observant handler to notice what has truly been searched and what the dog has speed read.  These dogs are speed readers rather than readers for comprehension.

Efficient dogs are the comprehension readers of the Nosework world.  They are also extremely efficient in the energy that they will expend on a hide.  These dogs get the same information at the start line that the fast dogs get but the difference is in their reaction to new scent profiles that they encounter along the way.  These dogs are efficient in every sense of the word.  They will look for the most physically efficient path to solve all of the odor puzzle.   They will take the time to solve hide locations on the way to the hide that they detected first.  The result is careful sourcing and in the end, a higher rate of success.  These dogs may or may not have challenges with initial levels however once they reach NW3, their pass rate is exemplary.  They may not place in elements or overall, but by gosh, they get the job done!

Can a dog be BOTH fast AND efficient?  One would argue yes.  However I’m skeptical.  I think there are some handlers that can be so astute that they can dutifully help their dog to be more effective, however, a dog’s search inclination is pretty much written in stone.

So where does this leave us?

This in essence negates the concepts of placements or the number of tries to title as measurements of success.  Yes.  I am truly saying that a team that takes 12 or 15 tries to get to NW3 Elite is no better or worse than a team that sailed through… basically because it quite possibly could be an apples to oranges conversation.

In the end, the very best dog in the trial is the one who wags his tail the most.


© Stacy Barnett 2015