Dogs normally assess the environment around them by first using their superior sense of smell rather than by sight although breeds in the sight hound category have been bred to depend more on sight than other breeds.
Dogs are born blind and those that loose their sight later in life manage to cope far better than humans due to their acute sense of smell. They do this by making a memory map out of environmental photos so that the dog can relate its whereabouts by the scents it detects in various different directions. This is why blind dogs are far less stresed if they are given the opportunity to explore areas that they visit on a regular basis, rather than new walks in strange and alien environments.
Dogs have an amazing sense of smell. When they sniff the environment around them their brains can assess and store enormous amounts of information in their memory by using their incredibly sensitive noses. Dogs really enjoy doing this as it mentally stretches their brain, tiring them in a pleasant way, and fulfilling their strong desire to work.
Sadly, because humans depend far more on sight and sound to communicate and understand what is happening around us, we have very little understanding of how important a dog's sense of smell is to their everyday life and mental well-being. This is because our sense of smell is very poor in comparison to that of a dog - humans have approximately 5 million scent receptors in their nose while the average dog has over 200 million, and working dogs such as scent hounds can have between 230 to 300 million. Another way of describing how amazing a dog's sense of smell is to use the analogy of a dog being able to find a single grain of sand on a 10m square patch of a beach!
SCENT IS THE MOST HIGHLY DEVELOPED OF ALL A DOG'S SENSES
HOW A DOG'S NOSE WORKS
When a dog takes a short deep sniff (rather than normal breathing) moisture on the surface of a dog's nose helps to capture scent molecules in the air and dissolve them. These molecules then come into contact with the olfactory membranes deep inside the dog's nose which send nerve impulses to the olfactory centre of the brain (which is forty times larger in ratio to the olfactory centre of a human brain). These nasal membranes cover the nose's wafer-thin turbinate bones and have convoluted folds to ensure that the minutest amount of scent can be captured within them and assessed accurately.
Dogs also have the ability to detect sex scent as the molecules in the air come in contact with the roof of their mouths and trigger the vomeronasal organ situated there. This organ transmits information directly to the limbic system of the brain which controls the dog's emotional behaviour.
Swedish scientists have recently discovered that dogs have heat (ie. infrared) detectors alongside the scent receptors in their nasal cavity. This enables hunting dogs to sense a prey's body heat when the dog is downwind of it.
EXAMPLES OF HOW ACUTE A DOG'S SENSE OF SMELL ARE
Scientist have proved that a dog can detect one part in a million of scent in distilled water. This ability to detect and differentiate scents has resulted in dogs being used throughout the world for detection and rescue, not just for hunting.
Dogs detect scent molecules in two different ways - sniffing the air for traces of a particular scent, or from sniffing the ground or objects with scent on. Some dogs seem to have a preference for air scenting or ground scenting but all dogs are capable of doing both to some degree or other.
Air scent occurs when a disturbance is made by whatever has recently passed through the air (eg. an animal, human, or a toy that has been thrown for the dog to retrieve - see Find it). It is affected by atmospheric conditions - temperature, humidity, wind speed and direction - and the time that has elapsed since the air was disturbed. Air scent disappears more quickly than ground scent.
LOST DOG IN NEW LOCATION?
If the handler is walking the dog in a new location, the dog has no environmental photos of the area. Therefore, if the dog should become lost or disorientated after following a really exciting track or chasing prey, it is very important that the handler remain in the vicinity of where the dog last smelt or saw them before it went off and got lost. The dog can then retrace its steps/scent back to the handler. (see Sound for advice about calling to your dog in such situations - don't shout)
Tuna Tracking mimics ground scenting by leaving a very unusual but highly stimulating ground scent which the dog has usually not come across before. The dog soon realises that this exciting scent game only happens when their handler is around and so it builds a strong bond with the handler and the dog is far less likely to wander off and "read the newspaper".
One of the biggest and most enjoyable benefits of watching your dog working with its nose is that you begin to understand and learn about your dog's body language and relate the same signals to other aspects of the dog's life.
For instance, dogs often hold their tail in a particular way when they are really concentrating. I have noticed this with one of my collies who loves to play all sorts of different nose games with me - when he is really focused he raises his tail very high and curves it over his back. I recognised the same body language when I was teaching him to go over a dogwalk in agility and realised that he was concentrating just as hard on learning this new "game" as he was when following a scent. I recognised his concentration and commitment and gave him plenty of praise and reward for working so hard.
Other changes in body language that you may see in your dog when using its sense of smell are -
DON'T TALK OR MOVE - IT WILL DISTRACT YOUR DOG!
Dogs need and enjoy using their brains to detect, analyse and assess scents in their environment. However, they are unable to concentrate properly if they are distracted by movements or sounds from nearby. Therefore, resist the temptation to talk to your dog in any way until the dog has found the end of the track, object or finished the exercise. If you praise your dog by saying "good boy" while it is still working, it will stop sniffing the ground as these words are usually said as a *release command to finish a training exercise. Also try to keep your body movements to a minimum when your dog is deep in concentration.
Dogs are able to cope if they lose their sense of taste, hearing or sight but find life extremely difficult to cope with if their sense of smell is impaired or lost - it is the equivalent of a human becoming deaf, dumb and blind and having to live alone in modern society.
One of my dogs wears a plastic "basket" type muzzle when *walking off-lead, yet he has no problems at all sniffing around and following any scent or track that he comes across. He wears the muzzle because when he is excited from chasing rabbits or squirrels, his adrenaline levels rise sharply and he occasionally chases after cyclists or joggers that happen to be passing at the "wrong time or place". With the muzzle on I have no worries about him causing any harm to anyone (or rabbit or squirrel!) and can allow him the freedom to exercise his body and mind in a safe and controlled manner.
WHAT DOGS USE THEIR NOSE FOR
IN THE BEGINNING....
From the moment that a puppy is born the first sense it uses is scent as it blindly searches for its mother's teat and begins to suckle. This is the puppy's first Environmental photo - the smell of the milk and its mother, the taste of the milk in its mouth, and the heat and physical closeness of its mother are all perceived as very rewarding and pleasant and will be remembered for the rest of the dog's life. Over the next couple of days the puppy will depend solely on its sense of smell to explore its surroundings and these early "photos" can have a profound effect on the puppy's development and how it will perceive its world for the rest of its life.
With this in mind, an old towel with the breeder's scent on it (and later on the pup's prospective new owner's scent) can be left in the whelping box so that the puppy builds up strong and happy associations ("photos") with the scent and will feel at ease when they meet the humans. However, make sure that the towel does not have a strong chemical scent on it that will "pollute" the human's scent that you are trying to introduce to the puppy.
Also be aware that too much exposure to too many scents can confuse and stress puppies and so I recommend the introduction of ONLY ONE ORGANIC TYPE SCENT A DAY that the puppy will eventually come in contact with as it grows older. For instance, the saturated scent of one of the following can be put on the tip of a cotton bud and held in front of the young puppy's nostrils. Make sure that the puppy does not come in contact with the cotton bud (there may be harmful germs present) and that the puppy is not held or restrained - otherwise it may build up unpleasant associations with the scent and affect the puppy's behaviour when it comes across it later in life. Instead, the breeder should stroke the puppy in a calm and pleasant manner so that the puppy feels confident and at ease with the new and exciting scent.
* Only one variety of the scent on a cotton bud at a time.
MORE EXPERIENCES AND THEIR BENEFITS
When the puppy is weaned and introduced to its new home, more interesting scents should be left on a variety of different articles, once again one scent at a time. For instance, put an interesting new scent on -
The puppy can then be introduced to various *Mind Games to help it develop and explore further its amazing sense of smell . This can also be done with dogs of any age or background.
There are many amazing benefits of introducing new and interesting scents to dogs rather than just letting it make its own entertainment by "Reading the Newspaper". The dog -
Some breeds, such as scent hounds, have been specifically bred to have very high nose sensitivity and these breeds often have the distinctive appearance of having either -
The jowls, ears and folds of skin act like an umbrella around the dogs amazingly sensitive nose, enabling the dog to confine the scent molecules on the ground without the wind blowing them away while their ultra efficient wet noses detect the slightest scent so that it can be analysed and assessed by its brain.
HUNTING AND TRACKING
Tracking dogs, such as the Bloodhound or the Elkhound, have been bred to have phenomenal powers of mental and physical stamina so that they can concentrate on following one particular scent over long distances without being distracted by any other scents that they may detect while tracking. Depending on weather conditions and the terrain that they are working on, these dogs are able to follow tracks that are sometimes over 24 hours old and can differentiate between old tracks and those that have been made more recently.
On the other hand, flushing dogs are bred NOT to concentrate on following just one scent but to move quickly and erratically in the undergrowth and drive the prey out for the hunter to shoot. I use the phrase "Spot Scenting" to describe the brief and random thought processes that these dogs have for any one particular scent, or use the analogy of a butterfly moving haphazardly from one flower head to another in its search for nectar.
COMMUNICATION - see "READING THE NEWSPAPER"
Although it is fairly obvious that dogs use body language and sound to communicate with one another, we often misunderstand how important scent is for communication between dogs and, to a lesser extent, other animals. Scent is a major factor in a dog's social development, not only as a puppy but throughout its life.
Dogs communicate by leaving their scent in six different ways -
* If a dog is unable to relieve itself outside its own house and garden, it is often a sign of its insecurity and anxiety as to its rank and status in the "dog world of scent " that it is walked in. I am always pleased to see a dog relieve itself when it comes to Dog Games training for the first (and even subsequent) time as the dog feels relaxed and comfortable enough in the environment to leave a "message" for the other dogs to find (even though we clear the poo away, of course, after each dog has been trained!). This scent "message" also acts as a Rewarding Environmental Photo so that the dog recognises that it has been relaxed and happy in the training area the next time it comes, whether it be a week or even two or three weeks between visits.
A dog's sense of smell is so acute, it is able to differentiate another dog's -
I like to compare this sniffing to humans reading - hence my expression "reading the newspaper" - and the scents that they leave behind "writing on the newspaper"! It is a vital part of a dog's life that it is able to "read" and "write" as it enables the dog to communicate with other dogs without having to physically be there. What dogs find so rewarding and satisfying about "reading the newspaper" is that every dog's "scent message" will be subtly different from the ones it did the day before. They enjoy the mental stimulation of reanalysing the scents to search for these subtle changes.
A classic example of dogs "reading the newspaper" is when I return home after training and/or being near to other dogs. My three dogs take great delight and concentration in sniffing me (especially my hands and trousers) to find out everything they can about the dogs I came in contact or close proximity too.
Many dogs are also apprehensive about coming too close to another dog and enjoy communicating by sniffing the other dog's scent "messages" and leaving their own "message" for the other dog to smell later on. This "reading the newspaper" is particularly useful when introducing dogs to a new neighbourhood or training venue, as the dogs can learn a great deal about each other by sniffing each other's markings before actually meeting and displaying body language to each other.
Dogs can become very frustrated and/or lonely because of the huge gulf of misunderstandings and lack of communication between themselves and their human "pack" (see Lodgers). For instance -
Therefore, detecting and analysing scents of other dogs can be even more important to these dogs who are starved of communication and welcome any type of contact with their own species. Dogs also leave their scent to mark the boundaries of their territory. This warns other dogs to respect these boundaries and not to trespass. This is often backed up with barking if dogs come too close to their territory.
HUMAN EMOTIONS SUCH AS FEAR (and HAPPINESS)
Dogs are also able to detect the human's pheromones caused by stress, excitement, anger, anxiety or apprehension. This is why dogs become fearful or aggressive when they are close to humans that are nervous (often because the human has been bitten or frightened by a dog in the past). The dog recognises the scent of fear on the human and thinks that they are going to attack the dog, so it attacks first in "self defense". This is also true for dogs that are fearful of other dogs - they become "victims" and are attacked by other dogs because they can detect the fearful dog's pheromones either on the ground or in the air and believe that it will attack them.
One sad example of a dog picking up a human's apprehension was a dog I knew that became fearful and withdrawn whenever the handler walked down steep slopes while walking the dogs. The dog picked up the handler's fear of falling over and became worried as well, even though it did not understand why the situation was fearful.
On the other hand, dogs can also be positively affected by the scent of pheromones given off by emotions such as calmness, happiness and contentment. If humans feel relaxed and calm, their scent triggers similar behaviours in their dogs as well.
Dogs will also sniff the ground to diffuse a stressful situation (see Calming Signals). The dog itself may be stressed and so it sniffs the ground in an attempt to find a pleasant experience or photo that will distract it and help lower its stress levels. In other instances, the dog may pick up the stress pheromones in a human and try to calm the human down by displaying this calming signal.
A human equivalent of this displacement activity is idly drawing or doodling as we think, twisting our hair in our fingers, rattling keys or coins in our pocket, or constantly playing with komboloi (Greek worry beads).
Because dogs have far more sensitive noses than their rather limited taste buds, the scent of their food is far more important than its taste. This is why dog food manufacturers sell so much processed dog food, as cooked meat smells far more appetising and palatable than raw meat (although cooked meat has far less nutritional value than raw and therefore has to have artificial additives added to the pet food).
A practical example of how dogs love to use their sense of smell is the use of Treat boxes in training. Rather than giving a treat to the dog in your hand, a tiny tasty treat is placed in a sealed treat box so that the dog cannot detect what treats the handler has on their person. When it is time to reward the dog the handler bends down and holds the treat box so that the dog can "steal" the tasty treat out of the box, licking and sniffing it inside and out just to make sure that the very last molecule has been licked from it. Even though the treat is gone in an instant, the whole process of sniffing and licking the box is very exciting, stimulating and rewarding to the dog and is a very strong motivator. Make sure that you have a wide assortment of scents of treats to choose from when placing the tiny morsel of food in the treat box - after all if the same type of food is given each time as a reward, there is little or no anticipation for the dog - it already knows what the treat is going to be as the handler gave it to them last time....
In conclusion if you find that your dog is sniffing a lot you may have to ask yourself these questions -
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