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Scent and Scenting (Part 1)

Scent and Scenting, Part 1

The main reason we have dogs when we go shooting is to find game that we could not find ourselves. First hunting up un-shot game hiding in cover and then secondly retrieving it from places we would find difficult to get to or tracking wounded game that has moved. Watching a dog use its nose is for me the most exhilarating part of working him. To see a dog that can really identify the scent he is looking for, stick with it, work out where the bird is or has gone and then home in on it before bringing it back to hand is fascinating, mesmerizing, and exciting. It brings the hair out on the back of my neck. Some dogs are born with what appears to be a good nose and are natural hunting dogs, sticking to a scent and determined to find the retrieve. At the other end of the spectrum, there are those that appear to have little ‘nose’ and may rely more on their eyes. In training our dogs, the development of ‘nose’ and scenting ability is essential if we are going to put game in the bag. The first step therefore is to watch and read a puppy and determine what type of dog he is. Does he give up when he cannot find a retrieve or does he stick at it? Does he seem to be able to follow the line of a rolling ball or does he stay in one place and not be able to work it out? Watching our dogs we can build a training program that will develop the strengths we need in the field and an essential one has to be scenting ability.

If a dog has difficulty in finding his retrieve and has to be right on top of it before finding, then naturally we may think scent is bad. But how much of it is bad scenting conditions and how much is poor nose, lack of experience, or the intelligence that gives the dog the ability to interpret scent? In our training we should give our dog every opportunity to build on his experience and also to develop his ability to understand, analyse and work scent. Too often I have struggled on a retrieve with one dog only to have second come in and find it as though there is a white flag marking the place. Nothing gives more satisfaction and pride than completing an ‘eye-wipe’ where your dog comes in and finds a bird that another dog or dogs could not find previously. We have to ask ourselves therefore what gives the successful dog the ‘edge’, the ability to find where others have failed. Were the first dogs carrying their heads at an incorrect level to touch the scent? Were they working too fast or too excitedly to even catch or recognize the scent? Was their brain and nose switched onto scenting or were they using just their eyes? There can be a number of reasons. The successful dog is one that can mark the fall and then when in the right area knows how to find and recognize scent and follow it to the retrieve.

The average dog has two hundred and twenty million scent receptors in its nose, we have five million. It has seven square metres of nasal membrane that catches the scent and directs it to the scent receptors; we have half a square metre. If we add to this the fact that the dog has a larger proportion of his brain devoted to scent interpretation, then we can begin to realise how important a feature of the dogs natural abilities his nose and scenting is. When breathing in, the speed of airflow increases through the dog’s nose because of it’s structure and this  ‘turbo charging’ enables more scent particles to hit and stick to the mucus on the nasal membranes. To help a dog determine the direction of scent it has ‘mobile’ nostrils, moving from side to side, and although breathing will bring scent to the dog, the sniff is completely different from our own. It is separate to breathing, does not disrupt it and places the odours on a separate bony structure known as the Subethmoidal shelf, which humans do not have.  From here the scent transfers onto the nasal membranes and the scent receptors. The other unique ability the dog has is to retain the scent above this shelf. Breathing out does not clean the shelf of odour, and scent molecules can accumulate. With this natural feature the dog has the ability to compare progressive sniffs more accurately than we can and therefore detect even the smallest increase in concentration of scent.

In addition to all these nasal abilities the dog also has a pouch lined with receptor cells above the roof of it’s mouth behind the incisor teeth, known as the vomeronasal organ.  Although there are theories regarding what this organ does, no one really knows, but with all this sensitive ‘apparatus’ installed it must be doing something. This pouch opens both into the mouth and the nose and it may be that as the dog begins to breath heavily through its mouth, this organ again detects scent and tells the dog to switch onto the nose where it can concentrate the odours and locate the source.

The other main factor that affects the efficiency of your dog’s scenting is of course your dogs ‘nose’ and brainpower.  It is thought that nose sensitivity is inherited, with the physical structure and brainpower being passed on from parents. Certainly scenting ability can be damaged by nasal infection but the physical damage will usually rectify itself. It therefore falls to us to build up our dogs experience and ability to read its nose. The trialing world has become very competitive in recent years with the standard of the top dogs increasing, in my opinion quite noticeably. Whether it is the hunting or retrieving breeds, there is more emphasis now on the dog’s game finding ability, and the top trainers spend a lot of time preparing their dogs by giving them real experience in the field on live game. Only in this way can the dog build up a wealth of experience on not only the behavior of game but also on the scents that it has to read to do it’s job.

When a dog works on scent he takes the scent from various sources, air scent, body scent left on vegetation or foot scent left on the ground. There are also theories that dogs recognize the crushed grass or broken vegetation where a bird or rabbit has passed. The dogs nose is so complex and such a wonder of natural science who are we to say they do not. When a dog tells me he does not recognize this I will believe those that say this is the case. With experience a dog will learn to relate all forms of scent to the find or retrieve he wants to make. He will learn the difference between a wounded bird and an un-shot one, he will learn to recognize the smallest amount of scent as being a bird or rabbit that has tucked in tight even though it does not move. He will learn to recognize the direction a bird has run by comparing the slightest difference in scent along the track it has taken. Scent direct from the body in the air or on vegetation is probably the easiest to understand but foot scent can be more complex, your dog may not be just trying to locate the scent of the animal but also reading the scent path from broken grass and other vegetation. There is also the thought that once an animal has been shot there will be a strong smell given off by the shot. The shot cutting through the air and leaving a trail is certainly of benefit to many dogs who learn to read it. Good dogs will be seen working to the gun, not only watching but also going to the shooter and then taking a line out from him along the path of the shot. To build the experience at reading this scent I will often use live cartridges to shoot towards a hidden dummy or have a thrower fire at a marked retrieve as it is thrown. I will also put empty cartridge cases in my dummy bag so the dummies get a touch of the powder scent. When shooting rabbits this is a valuable skill, however your dog will have to learn to move away from where the shot hit the ground and change from sticking on the strong shot scent to following a weaker one mixed with rabbit scent if the rabbit is wounded and moves. I have watched dogs learn this and have come to the conclusion that a dog that has been given experience learns to use his brain to determine which scent he should be following. He learns to set priorities of scent to follow and to learn, even reason, which is the best action to take to find the bird or rabbit we want. To achieve all this we train to build experience and scent intelligence. Some of this training is done in controlled exercises where we help and show the dog but a lot of the training is done where we allow the dog to teach himself and gain knowledge from experiencing different situations.