How many smells can a dog distinguish. The sense of smell of a dog. Smell is the most important canine sense. Now don't be surprised that a dog can recognize not only your smell, but also the smell of your car.

The modern theory of smell and odors, which still contains unresolved questions, belongs to the most complex areas of science. Despite numerous studies, this area of ​​knowledge is still full of "white spots". The information presented below, which is so necessary for working with PSS dogs, is only the most necessary in an extremely abbreviated form.

Smells are the main source of information received by the dog from the external environment throughout his life. Conditioned reflexes to smell are developed in her faster and more easily than to any other stimulus, and are more stable.

The characteristic features of the olfactory system of dogs, as well as other mammals, are, in addition to high absolute sensitivity to certain substances, the high speed of high-precision analysis, the identification of individual components in complex mixtures, as well as the ability to memorize mixtures of many components and their subsequent recognition even with a partial change in composition. . Moreover, the olfactory system of dogs can detect complex mixtures of odors and recognize them as a single stimulus. This unique property does not require the separation of mixtures into components, which is necessary for laboratory analysis. The ability of the olfactory system to make subtle distinctions between mixtures containing the same components but in different proportions makes it a particularly valuable information system.

The olfactory system of mammals is highly sensitive to a large number of substances. According to the definition of odorologist K. Sulimov, “the olfactory act can be considered as a process of recoding information from odorous substances into nerve impulses, as a result of the analysis of which the individual receives the necessary information, followed by a certain behavioral reaction under certain conditions and internal state, including individual experience” .

Smell and flair are close concepts, but not identical. The sense of smell is the physiological ability of an animal organism to perceive and distinguish smells in general. Sense in a broad sense - the ability of an animal to detect any source of the smell of interest to it through the senses, mainly smell.

In dog breeding, instinct is understood as the ability of a dog to detect a very specific source of the desired smell - a person, game, a mineral, etc. Hunters put into the concept of instinct not only olfactory abilities, but also hearing and vision, which dogs always use in combination, which greatly helps them at work.

Dogs "smell with their ears" due to a certain physical and physiological pattern. For example, on a snowy surface, the sound coming from the victim from the snow blockage experiences total internal reflection, except for a small conical zone directly above the sound source. The sounds emitted by the victim have a wavelength much shorter than a person's height. Therefore, only a dog whose ears are much closer to the surface of the snow can hear them. The passage of the voice of rescuers into the depths of the blockage is also difficult. For this reason, with good audibility of steps, probes - everything that moves directly on the snow, the victim in the blockage does not hear the voices of people, but hears the barking of a dog.

Dogs hear better than humans due to their increased sensitivity to high frequency sounds. The upper limit of the auditory range in humans is about 20 thousand Hz, in dogs - up to 40 thousand Hz. Since dogs hear higher frequency sounds, they react to the sounds of technical devices from a TV channel remote switch, a room smoke indicator, an electronic flea collar, and others.

On average, a person can easily distinguish several thousand odors, and an experienced specialist - more than ten thousand. Flair is characterized by the dog's ability to smell well only the sources of smell needed in its service. In other words, not every good sense of smell is a good sense of smell, but a good sense of smell cannot exist without a good sense of smell.

It is important for the trainer and handler to understand and "feel" how complex the process is going on in the dog's body to detect the right smell. Only then the handler will become sensitive and attentive to the dog during the search for the victim, he will understand why, thanks to “management”, the search sometimes turns out to be fruitless. Then it will be clear why you can’t pull and pull the leash outside of work, on a walk, when the dog sniffs, sniffs and, moreover, smells something. Her brain centers, including ERD, work only when receiving odor information, without this they are inactive and weaken, not to mention the weakening of the instinct itself. What is important is not the theory of the mechanism of taking smells, what is important is the practice of never interfering with the work of the dog's olfactory apparatus.

Sense of smell - concepts and their corresponding dictionary meanings are not identical and are not synonymous when evaluating the work of dogs. In colloquial language, "scent", in addition to the olfactory abilities of the subject, means the dexterity to find something you need, his resourcefulness, ingenuity.

Many hunters use this word in the sense of the "sense" of the dog. However, "dog's scent" is a broader and more complex concept. It includes a whole complex of individual behavioral actions, such as quick assessment and unraveling of a complex situation, anticipation of its changes, dexterity in achieving a goal, and others. Using the concept of "sense" in training and rescue work, as a more definite, clear one, one should not ignore the "scent", which expands the characteristics of the dog in its work and everyday behavior.

From the behavior of animals, both wild and domestic, it follows that, depending on the task set by life, the situation, the level of development of the participating receptors and the ERD, the target actions of the same animal will differ significantly. So, making only a detour of its territory (yard, forest), a dog or a wolf in a calm state, with orienting behavior, mainly uses sense of smell(nose). But having caught the smell of a “stranger” (human, animal), it automatically turns on flair(nose + ears + eyes). If, when walking around the territory, the “stranger” is not detected, then certain centers of the central nervous system are additionally excited, and all reserves are included in the work - scent, ERD.

A novice dog makes a search using only the sense of smell (it reacts to all smells outside the site, etc.), its instinct is not yet developed. After completing the PSS course, she begins to work with her flair (of course, her sense of smell has not disappeared - she perceives all smells, but leaves those she does not need without attention). After 2 years of work, she uses tricks and cunning to find the source of the smell (FROM), that is, she has a sense of smell, which is possible only with the inclusion of an ERD.

Obtaining odor information and the possibility of physical activity are necessary conditions for the full life of dogs, as well as other animals. For this reason, the manifestation of ERD in them is associated precisely with these physiological functions. The manifestation of ERD in all animals occurs in difficult, extreme situations, when instinctive behavior and individual learning do not ensure the fulfillment of new actions in their life, in new environmental conditions. An extreme situation is characterized by altered afferentation (impulses in the central nervous system from the sense organs) and the presence of a risk factor.

There is not a single kind of sensation that cannot be developed through training. It is systematic, regular training to find the source of the desired smell that is the best way to ensure that the dog has a well-developed, sharp sense of smell. The ability to detect the desired smell in trained dogs is several times greater than in untrained ones.

The sharpness of the flair is determined by the threshold concentration of the captured odor and the ability to process it in such a way as to accurately differentiate the desired odor from others and determine its location. Therefore, the sharpness of a dog's sense of smell depends not only on the sensitivity of the olfactory cells, but also on the analysis of odor information in the processing parts of the brain.

In the dog, the sense of smell is in the first place in terms of development, hearing is in the second, and vision is in the third. It is no coincidence, therefore, that the sense of smell is the first of the distant analyzers to begin and the last to end functioning in her life. Despite this, the complex stimulus formed from the visual and olfactory components is perceived by the dog's nervous system as a single synthetic stimulus, and not the sum of its components. The integration of the olfactory and visual analyzers is determined by the close functional relationship between the visual and olfactory systems.

A temporary aggravation of the dog's sense of smell can be caused by some artificial methods. The stimulation method consists in the fact that a few minutes before the search, they play with the dog, run around - they increase its general nervous activity. Before the command "Search!" for several seconds, they scratch her hair excitingly, pronounce the nickname with increasing intonation. Before the launch, the dog's nasal openings are covered with a hand, which forces it to take the deepest possible breath after removing the hand. These techniques often help her to catch the smell of even a subthreshold concentration from the spot.

In addition to instinct, a whole complex of sensory systems is involved in finding the PSS of the victim by the dog. In addition to rational activity, the search ability of the dog, its motor apparatus based on the predominant orienting-search behavior, plays an equally important role. It is preceded from puppyhood by an orienting reaction, which is later improved and transformed through education, training and training. In the domestic literature, due to the lack of an exact concept and term, there are other names close to them - "orienting-research", "olfactory-search", etc. Among the various types of behavior manifested by external and internal stimulation of the central nervous system, more often one of them is more pronounced in a dog, is predominant.

Approximate type of behavior to new or unusual strength stimuli manifests itself in the form of cognitive reflexes by sniffing, listening, looking, licking, digging. In the process of learning with the accumulation of conditioned reflexes, the orienting reaction manifests itself more moderately and, uniting with them, provides the dog with orientation in a new life situation. This reaction, depending on the conditions of learning and the life of the dog, is modified and replaced by a new one - most often orienting-search, defensive, and others.

The timing of the onset and degree of manifestation of the initial orienting reflex and its transition to mature, for example, orienting-search, behavior depends on the degree of anatomical and physiological maturity of the relevant organs. An orienting reaction is manifested in puppies from the first day of life, first to smell and taste stimuli. To smell - the orienting reaction is immediately distinguished by its persistence and clear expression, which is of vital importance.

Following the development of olfactory, gustatory and tactile analyzers, there is a gradual maturation and inclusion of others - auditory and visual. These distant analyzers perceive and process distant signals, due to which the puppy's connections with the environment expand and become more complicated. His free movement around the area and the development of the motor apparatus is a new stage in life. The capture of olfactory and all other stimuli is closely connected and intertwined with motor reactions, forming a complex search behavior.

Restricted by "an apartment and a leash", the richest innate qualities of a puppy do not develop, but are oppressed and deaf. For this reason, it is more difficult to make a PSS dog out of a puppy with the best "show" pedigrees, grown up to a year old in a city apartment, than out of a homeless mongrel, in which all these innate qualities were not oppressed, but developed in the natural conditions of life.

Approximate search(OP) behavior provides animals in natural conditions with finding prey, food, water, etc. In the process of life and learning of an individual, this reaction is conditioned by a multitude of conditioned reflexes and forms complexes with other behavioral reactions. The work of service and hunting dogs with "upper and lower" flair, their combination is entirely carried out on an orienting-search reaction. For dogs of all services, this reaction is of paramount importance.

On the basis of EP, such behavior as “a sense of direction” develops - the dog is hundreds of kilometers away from his home, a rescue station; "sense of danger" - the presence of the dog's enemies, dangerous places on the terrain, etc. With training, training and constant work of the OP, behavior moves to a higher level - search and investigation.

Although this reaction is potentially present in many dogs, in some it may be mild and not predominant. Determining the degree of its severity is very important when acquiring dogs and choosing a method for training them.

Search and survey(ON) behavior It is characterized by the fact that if in OP the dog more or less quickly only looks for and finds an invisible victim, then in PO it precisely “examines” this area in the most thorough way, where there may not be a victim. She does this not on command, but only with the light promptings of her guide. With such an examination, the time spent is not considered. If there were no victims at the site, then the result of the work is no less important - the guide signs the document: “There are no victims at the surveyed site.”

But it also happens that the smell of a subthreshold concentration, which is usually not caught, accumulates in the dog's olfactory apparatus when the dog exhibits software behavior - the concentration reaches the threshold and the victim is "miraculously" detected. This behavior usually shows up in older dogs. It is they who can perform a qualitatively “detailed examination”, while young dogs more often, raising their noses, try to catch the smell with their upper senses.

The attachment reaction is a complex dog behavior in the form of caressing, obedience, waiting, following the owner, and so on. This is an innate behavior based on the "inheritance" received from centuries of communication and joint actions of a person with a dog. Attachment, reinforced by care and attention, is the most important reaction, the basis of a strong contact between the trainer and the dog, without which training is impossible. This behavior is at the heart of the Swiss PSS dog training method. The work of a rescue dog is possible only with a well-developed attachment, since in difficult and dangerous conditions the dog seeks and finds an unfamiliar victim, receiving satisfaction and joy from this.

No matter how keen the dog's instinct, the work is reduced to zero without its informational connections with the handler. These two-way links are complex, dynamic, and multichannel. In service dogs, they are almost entirely developed by training, in hunting dogs, to a large extent - due to innate reactions and natural conditioned reflexes formed to the natural properties and qualities of unconditioned stimuli. For example, a dog develops a natural conditioned reflex to appearance, voice, individual smell, certain actions of the handler and his assistant. Exceptionally important in working with a dog is the feedback: from the dog to the person. The difficulty and complexity of such a connection is due to the fact that the dog of the PSS, like other services, although it can distinguish scent shades well, does not know how to react to them and notify, for example, a living person or a corpse in a blockage.

To teach a dog to react differently to various odor stimuli is the task of its training. In order for the handler to be able to timely and accurately understand all the actions of the dog associated with its work, the odor information perceived and processed by the olfactory analyzer of the dog must, by conditioned reflex, include the corresponding visual or auditory signals accessible to human perception. Essentially, almost all the special training of dogs and the development of their breed qualities in the use of an odor analyzer is reduced to the development of reflexes and natural reactions in them that provide feedback from a dog to a person. Such a connection is carried out by translating the perceived odor information by the animal into the language of visual and auditory signals.

In order for such a connection to be reliable, and the transmitted information to be reliable, the development of signal behavior in a dog must be carried out taking into account the stereotype of the working state that is formed in this case, ensuring a balance between pathogens and inhibitory processes. Therefore, for example, not every signal that can be developed in a dog by the skill of a trainer turns out to be expedient, and far from any training technique is rational for teaching PSS dogs.

Biorhythms play an important role in the work connected with flair for the dog. Ignoring them will not allow you to make the search effective, to make the most of its service capabilities. Biorhythms - a periodic alternation of a state of greater activity of physical, mental, intuition and a decrease in activity - are divided into external and internal. The manifestation of external is associated with periods of solar activity, seasons, time of day and other cyclical phenomena.

Internal biorhythms act under the influence of the neuro-humoral system, endocrine glands. Of particular importance for instinct is the daily biorhythm, which forms periods of maximum efficiency and lethargy. There is a maximum activity - morning (from 8 to 12 o'clock) and evening (from 18 to 24 o'clock), a decrease and a minimum of activity - in the middle of the day and at night. These hourly data are very approximate and are adjusted for the dog's personality and specific environmental conditions.

A complex system of biorhythms requires a clear correspondence between their alternation and the volume and complexity of the work given to the dog. Violation of this correspondence leads to general diseases of the body, weakening of the sharpness of the senses, neuroses.

Sense failure - partial or complete failure of the dog's olfactory abilities to perform work carried out in conjunction with other sensory systems. He negates the highest level of her training and skills acquired over the years of work, nullifying the chances of the dog finding a victim suffocating in the rubble.

The simplest and quickly passing breakdown is general physical fatigue or from prolonged work with the upper and lower senses. No less dangerous is the overstrain of nervous activity, leading to neurosis. Overheating and hypothermia, lowering the sharpness of the senses during work, can subsequently lead to diseases of both the respiratory tract and the whole organism.

It should always be taken into account that a dog receives a large dose of toxic substances compared to a person, since impurities usually settle, air movement in the surface layer is weaker, which makes it difficult to purify.

If the dog is exposed to the same smell for a long time, the sense of it weakens, later he may stop smelling it at all. There is an adaptation to this smell, explained by a decrease in the intensity of nerve excitations transmitted from receptors to the brain. In order for the dog to feel it again, it is necessary to remove it for some time from the zone of action of this smell.

Adaptation should be distinguished from general fatigue during a long search due to high physical and nervous activity during muscle load, capture and processing of odor information. Therefore, during prolonged work, every 50 minutes, dogs should be given a 5-10-minute rest.

The clogging of the respiratory organs with soil, snow dust and smoke has a harmful effect on the instinct of dogs. A more harmful effect, causing functional disorders of the nervous system and the whole organism, is exerted by gases and aerosols of toxic chemical compounds. For example, inhalation by a dog even for a short time of the exhaust gases of cars sharply lowers its instinct, can lead to illness and death. With rhinitis and other diseases of the respiratory tract, the dog is given peace, since the quality of its search work will be below average, and the tension of diseased organs will lead to an exacerbation of the disease. Transportation (not even fast) over long distances from one time zone to another disrupts the biorhythm of the body and the sharpness of the flair.

It has been established that the lack of vitamin A in dogs' food, large impurities of hot spices (pepper, horseradish, etc.) significantly weaken their flair. The olfactory apparatus of dogs is extremely sensitive to external stimuli, even eating a few pieces of spicy cheese weakens the sharpness of her instincts for some time.

The PSS dog is the most precise instrument, and therefore it must be treated precisely as with the most precise instrument.

In nature, there are a huge number of different odorous substances of animal, vegetable and mineral origin. All these substances that cause the sensation of smell are called odorous, or odorants, which, according to the duration of their action, are divided into persistent and unstable.

In order for a dog to detect any persistent and strong odorant, it must not be isolated from the environment. No dog of the highest qualification will detect the smell if it is inside a brewed glass dish or at the bottom of a flowing river. For a dog to take a smell, it is necessary that the source of the smell, that is, the release of odorous particles into the environment, be open. However, at the highest concentration of the odorant emitted by the odorant, the effect of the adsorbent - the odor-absorbing substance - and the environment can be so unfavorable that it will be below its threshold concentration - the lowest concentration of the odorant that causes the sensation of smell - for a given dog at a given moment. The threshold concentration is usually expressed by the number of substance molecules per 1 cm 3 of air and is different for different odors.

The factors that are detrimental to the dog's taking of the smell, in addition to the mentioned blocking, are the following:

1) a thick layer of an adsorbent medium (soil, snow, etc.), through which the smell does not come to the surface;

2) a storm wind that disperses and carries away the smell instantly. Therefore, in order for a dog to detect an odor, not only the odorant itself is necessary, but also the following elements:

odorant– presence of IS – threshold concentration – dog sniffing

Differentiation of odors felt by a dog occurs only with the coordinated work of its perceiving and analyzing parts of the higher nervous system. Only in this case, the dog can isolate the desired smell from many others, including those very close to it or stronger, and differentiate the individual smell of a person. Of the many homogeneous objects, she finds exactly the one that the trainer barely touched with his fingertips, even after being held by other people.

A good detective dog, when taking a trail of a person, distinguishes his smell from hundreds of others that may be more recent. The ability of dogs to differentiate odors is based on their use to select the desired person by the smell left by him on the subject.

It is curious that dogs, while quickly and accurately distinguishing the smell of what they are looking for from hundreds of people, cannot distinguish the individual smells of two identical twins from each other. This suggests that the individual smell of a person is genetically predetermined, since only identical twins have the same genetic constitution and almost the same individual smell. When the dog was allowed to sniff the scent of one of the twins, it confidently followed the trail of the other. However, if the twins, having laid a common trail, diverged in different directions, the dog followed the trail of the twin whose scent it sniffed.

The smell of a person is a combination of his individual smell, including the smells of secretions from sweat and sebaceous glands, desquamated epithelium and substances released during pulmonary and tissue respiration. In addition, it includes household, industrial and other impurities that remain mainly on clothes and shoes, as well as the smell of used cosmetics, medicines, etc.

The smell of a person, which is a very complex bouquet, depends not only on the number of its components, but also on their quantitative ratios. Their composition can change not only in terms of quantity, but also quality, which depends on external and internal factors. The first includes temperature and other meteorological conditions of the external environment. To the second - changes in the intensity of metabolism during hard work, the use of drugs and odorous dishes, various diseases. Changing it can also cause the accumulation of skin secretions, when their urea and volatile fatty acids begin to decompose.

The smell of a person's body differs from the smell left by him on objects, quantitatively and qualitatively. The last difference is explained by the fact that the components of a person's individual odor are specific and, due to their volatility, cannot remain on objects for a long time. Of these, only the more resistant part, which has a slightly different quality, remains.

The odors of decomposing skin secretions are also specific, in addition, household and industrial odors may predominate in this case. These circumstances allow dogs to distinguish the smell of a person from his smell on objects and from a human corpse.

The following case testifies to how sharp the sense of experienced dogs is when differentiating the smell of a person from a corpse.

The traveler took refuge for the night in a small cave. In the morning, coming out of his hiding place, he fell under a rockfall and died. Soon a lifeguard arrived with a dog. She quickly led to the cave where the deceased spent the night ... As the rescuer said, the dog walked a few meters from the stiff corpse, but did not stop, but led further to the smell of a living person. It is well preserved in the cave, as in an "air closet". A learned and intelligent dog fulfilled the "law of the savior" - first to the living, then to the dead. There was no smell of a living person on the corpse.

When working with a dog, it should be borne in mind that the smell of a person is well absorbed and preserved by woolen and silk fabrics, worse than paper and synthetic ones. Its smell is well adsorbed by soil, dry wood, especially charcoal. Odors are destroyed by exposure to the rays of the sun, oxygen, ozone and a number of other agents. Therefore, in the search service, depending on the prescription of the trace laid by the person, that is, on how much its smell is weakened by the time the dog has worked it out, it is customary to subdivide the traces into fresh, normal and old (more than 3 hours).

Man as a "source of smell" has much in common with animals. This also applies to the release of volatile components into the environment. Many of them carry information about the species, gender, individual, his physiological, functional and emotional state. In addition to the permanent signs of the individual, these components can also reflect temporary, random ones - the place of a recent stay, the food eaten, the disruption of the functioning of any organ or the whole organism.

Contamination of the victim's clothes with strongly smelling substances - gasoline, technical oils, various chemicals - makes it difficult to find him. Although the dog feels along with them the smell of the person himself, but she reacts worse to him as to the right smell. There is a kind of anosmia, like a cop - to the smell of a hare's trail.

In order for a dog to catch a smell at some distance, its concentration in the air between the source and the dog must be at least the threshold. With complete stillness of the air, which almost never happens in real conditions, the smell on the surface of the earth spreads by diffusion evenly in all directions, in the form of an irregular sphere. The diffusion rate is not constant, it depends on atmospheric pressure, air temperature, molecular weight of odorous particles and other factors. The spread of smell in the absence of wind also occurs by convection, that is, the vertical movement of air between the upper and lower layers of the atmosphere, resulting from their uneven heating. It is also not constant and depends on the above factors.

Moving air with odor particles upwards reduces their number in the surface layer, making it difficult for the dog to take the smell. It goes without saying that in the training sessions the trainer will not figure out which of the laws the smell comes out of. His task is to understand these laws, not to act blindly and not to demand the impossible from the dog - to detect the smell where its concentration is below the threshold or it does not exist at all. In the real situation of rescue work, in a “hopeless situation”, sometimes it is necessary to stop unsuccessful searches and switch attention to where the victims can still be found and saved.

In order for the smell of a person who is under a layer of soil, snow, to be taken by a dog on the surface, he must first pass through this layer, which has a certain density, which can block its exit or be such a good adsorbent that it absorbs most of the smell.

There are 4 main types of media through which the smell comes out of the blockage.

1. Ruins of buildings, forest debris. Fragments of destroyed buildings, tree trunks, mixed with each other as a result of an earthquake or hurricane, leave such large cracks that the free passage of human smell through them is possible through a thickness of 10 meters or more. In cold weather, the release of odor to the surface is enhanced by the law of convection. Factors that make it difficult for a dog to smell include an abundance of household items with a human smell, smoke in the air from fires, and a large amount of dust.

2. Combined blockages. Fragments of destroyed buildings, tree trunks mixed with wet soil or snow as a result of a mudflow or an avalanche of wet snow make it difficult for the smell to reach the surface. It occurs more actively along the cracks near the protruding large fragments of wood and stones. The rapid compaction of the mud mass and the freezing of snow make it difficult to take the smell.

3. Avalanche, snow drift. The layer of snow formed after these disasters has a different structure and smells pass through in different ways. The most favorable for the release of the smell to the surface is large, not wet and not frozen, lumpy snow, in which there are quite large through pores. The high humidity and density, dusty structure, ice crust on the surface and the extremely variable state of snow complicate the passage of the smell.

4. Example forest blockage serves as a search for lumberjacks in Altai ...

After a hurricane wind and thunderstorms in the foothills, avalanches descended on a large area, and the forest fell down. According to the forestry, 3 lumberjacks worked on the littered area. The blockages were of a mixed nature - fallen, broken tree trunks, branches mixed with wet avalanche snow. The dog that started searching with the guide fell headlong into cedar branches mixed with frozen snow. She moved with difficulty, breathing heavily. Physically difficult and dangerous movement of the dog and handler made it difficult to orientate and conduct a clear search. The guide stretched out the tent and ordered the dog to stop searching.

In the morning, the frozen snow firmly held the branches and branches - it was easy to go. The dog sniffed sensitively, mostly with its lower senses. She moved slowly, stopping, sticking her nose between the branches ... It was the second hour of searching. But the conductor did not urge, did not urge her to search faster. The sun was rising, the ice crust on the snow was melting. Here the dog attacked the blockage, loud barking - the first lumberjack was found. Half an hour later, emboldened by finding the first, the dog found the other two lumberjacks.

The physical explanation for the release of the odor to be taken by the dog is as follows. For several hours of the night, the smell of a person diffused enough of the mass of blockage. Early in the morning, at the lowest air temperature, its convection intensified. The rays of the rising sun melted the ice crust of the blockage, and the smell of lumberjacks was on the surface.

No less important is the "physiological" side. In the morning and afternoon, the dog searched several times better than in the evening, for the reason that its “sense itself” was several times sharper. The road to the scene of the incident, the physical overload while moving through a difficult and dangerous blockage, the novelty for her of the blockage itself had a negative effect on the dog, as well as on any other. There was a generalization of the central nervous system instead of the concentration necessary for conducting an effective search for its concentration, that is, the concentration of all forces and attention for one goal - finding the smell of a person.

The explorer did the right thing in all respects by choosing this search tactic.

According to A.P. Orlov, the founder of the Russian Service of Ore Detecting Dogs, recorded cases of dogs taking the smell of ore located under a layer of water, over which, in addition, there was a layer of marsh soil.

This is a very complex process that occurs infrequently due to the relationship of meteorological and geographic conditions: the smell of ore saturates water - odor-saturated water, according to the “wick law” (capillarity phenomenon), rises through the soil to its surface and spreads in the air. Therefore, to search in an environment where water squelches under your feet is far from an empty business. At very low, “subthreshold” odor concentrations, dogs are helped by its accumulation by the olfactory organs.

The most favorable conditions for the transfer of smell by the wind are created by a flat open area with a low vegetation cover. Thus, when the dog is working with the upper sense, when he is doing the "primary" search, the wind is a facilitating factor.

However, when the dog switches to a “thorough” search, when he uses his lower sense, the wind often harms. It has been established that with distance from the odor source, the amount of odor information received decreases in proportion to the square of the distance. But it is not the remoteness of the source that is the main reason for the weakening of the smell, namely the unfavorable speed and nature of the wind. Optimal for the work of the dog, the lower sense is considered to be its speed up to 0.5 m / s. The decrease in the acquisition of odor information in strong winds is not only due to the mechanical dispersion of odor particles, but also due to their chemical transformation under the action of an increased amount of oxygen and ozone.

When searching, it should always be taken into account that the dog receives the maximum smell not with a direct headwind, but with a head-to-side wind at an angle of about 30 °. This is explained by the anatomical structure of the olfactory apparatus of animals, due to which, while on the move, they examine with the help of their senses with such a wind a much larger territory than with a direct oncoming one.

When the PSS dog completes the search for the victim, determining his exact location, and works mainly with his lower senses, a number of factors in addition to the wind influence the success of this operation. The most important of them is the humidity of the air, the increase of which helps its work. This is explained by the fact that with an increase in humidity, the desorption process slows down, that is, odor particles break off the soil surface more slowly and spread in the surrounding air for a longer time.

Low humidity adversely affects the dog's olfactory apparatus, drying out the mucous membrane of the nasal cavity. Light drizzle, increasing the humidity of the air, has a positive effect. Strong and thunderous rain washes away the smell from the surface, but does not prevent it from leaving the depths of the soil and snow. The formation of ozone in the air, which actively destroys odor particles, has a negative effect.

High surface temperatures of the soil and air affect the work of the dog negatively. The heated surface of the soil contributes to a more active flow of chemical reactions of oxidation of odor particles. In addition, the ground layer of air heats up from the heated soil, active convection occurs and the concentration of odor decreases below. Heating the air, in addition to activating these processes, leads to overheating of the dog's body, drying out of the nasal mucosa, shortness of breath and fatigue.

Notes:

Service dog breeding /Comp. V.N. Zubko. M., 1987.

Inaccurate names and expressions found in the literature on dog breeding make it difficult to understand the topic being presented. “Reaction of behavior” is a lexical inaccuracy. In animals, as in humans, in response to the irritations received by the nervous system, certain reactions of the body occur. There are no behavioral reactions, since all behavior is a chain of reactions. That's right - "indicative type of behavior", "indicative-search behavior." - Note here and below. ed.

The scent of a dog is probably its most amazing and interesting ability. The dog's sense of smell allows it to distinguish many smells, including old ones or at a great distance. In this article, we will talk about exactly how this sense organ works, how many smells a dog can distinguish, and how you can test its sense of smell.

Dog sense of smell: general characteristics

Dogs are known to be very sensitive to smells. By smell, your pet is able not only to find food and detect other animals at a considerable distance, but also to determine whether they are familiar or strangers, what gender they are, what their physical and emotional state is. With the help of the sense of smell, the dog distinguishes a huge number of objects and freely navigates the terrain. She constantly smells, and it would be more correct to say - she lives in the world of smells. Animals that rely heavily on their sense of smell are called macrosmatics, and it is to this group that dogs belong. People, on the other hand, belong to microsomatics, that is, we basically feel smells, but in general we are more guided by other senses.
Unlike humans, dogs can smell with a very high degree of accuracy. She is able to sense the presence of one molecule of an odorous substance in 1 liter of air or 1 milliliter of water. It has been established that under favorable conditions, the dog smells at a distance of up to 1 km from their sources, and sometimes even more. If we talk about how many smells dogs can catch, then the figure is very significant. It has been proven that they can distinguish up to 1,000,000 odors.

The sense of smell in dogs is developed at such a high level due to the structural features of the nasopharynx and brain. In particular, in the head of an animal, all odors are clearly differentiated by the slightest distinguishing features. In the mixture, the dog feels each “note” separately, even if some smell is stronger and others are weaker. This already shows how many times the scent of a dog is stronger than a person, because we smell, for example, perfumes or dishes as a whole and are not able to accurately break them down into ingredients, especially if one of them interrupts the rest. Interestingly, the dog not only perceives the smell by itself, but is also able to determine its concentration, strength and freshness. Studies have shown that she distinguishes smells by prescription with an accuracy of 3-5 minutes.

For people, it is of particular importance that dogs easily form conditioned reflexes to smells and their individual “parameters” (strength, prescription, individuality, etc.). This makes it possible to successfully train four-legged helpers and use their excellent flair for a variety of purposes.

Sensitivity to odors

Dogs don't smell very quickly. The odor molecules must not only penetrate the nasal mucosa, but also bind to the right receptor. It often takes a while for the dog to recognize the smell. Equivalent stimuli are needed to cross the olfactory threshold and elicit a response. When all specific olfactory receptors are involved, the dog's sense of smell decreases (mostly after 30-45 minutes) due to the so-called olfactory fatigue. Once it sets in, the dog needs to rest to give the receptors time to release. The dog's sensitivity to smells is optimal after 2-4 minutes after the start of work, the rest phase lasts 3-4 minutes. Every dog ​​has the ability to “read” smells to some extent.

The custom of all the surrounding dogs to urinate on the same pole is associated with survival and the ability to analyze the smell of urine, with the help of which, like wolves, they will find out which of the animals lives nearby.

And in conclusion - some useful information for guides of sniffer dogs.

• In females, the sense of smell is sharper than in males, but it depends on the estrous cycle (estrogen, like the male hormone testosterone, has a positive effect on it).
• Pigmentation of the nasal mucosa affects the olfactory ability. Dogs with light mucosa work less efficiently.
• Biological factors can affect a dog's sense of smell (hunger improves it, while poor general health or physical fatigue, on the contrary, reduces it).

Nose care: no special nasal care is required. But you need to remember that the nose at any time of the day should be wet and cool, normally it can be dry only during the dog's sleep. Chronic dryness of the nose in the presence of redness in the corners of the eyes can signal that the tear ducts are blocked. This means that your animal needs a visit to the doctor, as well as significant irritation or the presence of mucopurulent discharge from the nasal cavity.

The pattern on the nose is unique and individual for each dog, like human fingerprints, the pattern of which never repeats. Animals are identified by the pattern on the lobe.

The color of the nose in dogs depends on the color of the coat. So, for example, in individuals with white spots on the coat, the nose may be spotty, in red individuals the pigmentation is brown. But under the influence of external factors or diseases, pigmentation disorders of the nose are possible.

Nose of a healthy dog

It is generally accepted that the humidity of the nose can be judged on the state of health of the pet. A wet nose is a sign of good health, while a dry one signals possible problems, which is erroneous. The moisture in a healthy dog's nose can fluctuate throughout the day. Weather conditions, changing room temperature can be the causes of dry nose lobes. In addition, there are a number of other reasons why the lobe becomes dry, but not related to the pet's painful condition. So, for example, a dog's nose can become dry after a long stay of the animal in the sun, being near a heat source (fireplace, radiator), staying in a poorly ventilated room, with insufficient water consumption.

Of course, a dry nose can serve as one of the symptoms of a disease, but often diseases are accompanied by other symptoms, such as peeling, redness (sunburn) of the ear, and discharge.

Factors affecting the sense of smell

Despite the fact that dogs are considered to be among the best sniffers, there are many factors that can affect their sense of smell, which can either improve or worsen it. Let's look at the most common causes of differences in olfactory abilities in dogs and how to correct them.

Let's start with climatic conditions, which have a significant impact on the dog's sense of smell. With increased humidity and precipitation, the sense of smell worsens, as there are additional irritants and extraneous odors emanating from water and earth. It is because of this that it is so difficult for dogs to follow the trail in rainy weather or in bad weather conditions.

The next factor is air temperature. It would seem that how it can affect the sense of smell, but, in fact, the performance of the animal and its olfactory capabilities depend on the temperature. The temperature factor directly affects the condition of the dog's body. In extreme heat and high temperatures, the animal quickly gets tired, becomes lethargic, and its breathing quickens, which is why odors cease to be so sharply distinguished. In addition, elevated temperatures accelerate the volatilization of odors, which significantly weakens their strength. At low temperatures, on the contrary, odors persist much longer, however, during severe frosts, dogs also experience difficulty in taking a trace due to freezing of water particles on the mucous membrane.

The food that a dog eats also directly affects its sense of smell. Food that has a too strong and pungent odor can discourage the animal from smelling, and the longer the dog eats it, the weaker its scent will become. Odors such as herring, onion and other pungent odors should not be present in the animal's diet. The sharpness of the scent also depends on the type of meat. So, for example, lamb, and even lamb bone, can take away a dog's instinct for a long time. Therefore, you should be very responsible in choosing food for your pet.

Do not forget about the differences between dog breeds. Some of them have a more pronounced sense of smell, and some of them are slightly dulled. It is the breed that often determines whether a dog is suitable for search work or not. Some breeds have an innate ability, laid down at the genetic level, to take a trail and lead it, you just need to be able to develop it correctly.

How to keep the scent

In order for the dog to distinguish smells well, it should not be tired. An exhausted and lethargic dog distinguishes smells much worse and is not able to react sharply to their changes and interruptions. But, in addition to general fatigue, there is also olfactory fatigue. When walking for a long time on the trail and inhaling odors, the sense of smell is slightly dulled, in order to restore it, the dog must be given a little time to rest by placing it in fresh air and not giving any tasks to search for objects. Do not forget about the proper care of the dog's nose, the condition of which directly affects the quality of the scent. Under normal conditions, the surface of the nose should be damp and cold; it can only be dry when the animal is sleeping. If your pet is sick or overtired, his nose will become dry, this will be a signal to take appropriate action. The animal must be taken to an appointment with a veterinarian, who will find out the cause of the disease and prescribe the appropriate treatment. A wet nose allows the dog to absorb odors from the air, and in the absence of moisture, the ability to distinguish odors is significantly reduced and the sense of smell decreases.

A feeling that has no equal.

Smell- the most important feeling of a dog. Throughout centuries of evolution, a wild dog had to follow the trail in the right direction, otherwise it would die of hunger. The dog uses it for hunting, for orientation in the area, when communicating with other animals and determining their taste preferences. A dog recognizes its owners and its home by smell rather than sight. The sense of smell is also important for assessing the quality of food and its choice - in this it even prevails over taste sensations. If the dog does not like the smell of food, she refuses it.

The olfactory sensitivity of dogs is almost a million times greater than that of humans. Dogs have 40 times more odor-recognizing cells in their brains. Strong sensitivity to odors is also due to the large area of ​​the receptor organ: in a dog, the area of ​​the mucous membrane of the olfactory region of the nose is approximately equal to the total area of ​​​​its skin, while in humans it is only a few square centimeters (about the size of a postage stamp).

The number of olfactory cells in dogs is very high, although it varies depending on the breed (for example, in Labradors and German Shepherds - 220 million, in Cocker Spaniels - 70 million). Importantly, the region of the brain responsible for recognizing olfactory stimuli is almost 10 times larger in dogs than in humans.

Perception of smell.

The structure of the nasal cavities in dogs contributes to the good development of the sense of smell. The nasal conchas are lined with a mucous membrane, equipped with many olfactory receptors. Every healthy dog ​​has a very moist nose, the moisture washing over the receptor cells. And since all odors are chemical in nature, they instantly dissolve in this liquid. The nasal conchas have a spirally curved shape and are separated by sinuses (sinuses), into which flows of inhaled air enter along with odors. Another organ of smell is the ethmoid bone in the depths of the nasal cavity, which also contains sensory cells. Five cranial nerves are also involved in the perception of smells in dogs.

Molecules of aromatic substances, coming into contact with these sensitive cells, bind to specific receptors, causing chemical reactions, as a result of which a signal is sent through the olfactory nerve to the corresponding area of ​​the brain, where the information received is processed. Currently, more than 300 types of olfactory receptors have been discovered, each of which is associated with a specific "odotope" (part of a chemical molecule) - the odor determinant. A dog can distinguish up to 2 million smells. The degree of perception of the smell of an aromatic substance depends on its chemical composition, molecular weight and humidity of the inhaled air. Heavy molecules, sparingly soluble in water, are perceived more easily. These principles underlie the work of sniffing dogs used in the service and search service - from search and rescue operations to the detection of drugs, weapons and explosives.

Sensitivity to odors.

Dogs don't smell very quickly. The odor molecules must not only penetrate the nasal mucosa, but also bind to the right receptor. It often takes a while for the dog to recognize the smell. Equivalent stimuli are needed to cross the olfactory threshold and elicit a response. When all specific olfactory receptors are involved, the dog's sense of smell decreases (mostly after 30-45 minutes) due to the so-called olfactory fatigue. Once it sets in, the dog needs to rest to give the receptors time to release. The dog's sensitivity to smells is optimal after 2-4 minutes after the start of work, the rest phase lasts 3-4 minutes. Every dog ​​has the ability to “read” smells to some extent.

The custom of all the surrounding dogs to urinate on the same pole is associated with survival and the ability to analyze the smell of urine, with the help of which, like wolves, they will find out which of the animals lives nearby.

And in conclusion - some useful information for guides of sniffer dogs.

• Bitches have a sharper sense of smell than in males, but it depends on the estrous cycle (estrogen, like the male hormone testosterone, has a positive effect on it).
• Pigmentation nasal mucosa affects the olfactory ability. Dogs with light mucosa work less efficiently.
• At the sharpness of smell dogs can affect biological factors(hunger improves it, while poor general health or physical fatigue, on the contrary, reduces it).

Nose care: no special nasal care is required. But you need to remember that the nose at any time of the day should be wet and cool, normally it can be dry only during the dog's sleep. Chronic dryness of the nose in the presence of redness in the corners of the eyes can signal that the tear ducts are blocked. This means that your animal needs a visit to the doctor, as well as significant irritation or the presence of mucopurulent discharge from the nasal cavity.

The main sensory organ in dogs is the sense of smell. The sense of smell in this animal, unlike humans, is much better developed. Even the smallest lap dog is able to perceive the subtlest odors, the presence of which the population of the globe is not even aware of. The mucous membrane of the dog's olfactory organs is tens of thousands of times more sensitive than the human nose, and the area of ​​the brain and cortex where the corresponding impulses arrive is much more developed.

It is impossible to miss such a moment that the dog tends to remember smells and associate them with the past. There is plenty of evidence for this.

The most memorable for this animal are the circumstances that had any negative character for it.

Hearing and smell in dogs

All this is understandable. The animal often behaves very carefully, trying to avoid dangers. Both negative and positive emotions, as well as the olfactory senses associated with them, are stored in the animal's memory for a long time.

From the inside, the nasal cavity and upper respiratory tract are lined with a layer of cells containing a large number of chemical receptors. Having a characteristic bone structure, air, entering the nasal passage, passes through a large area, in contact with a large number of cells and villi responsible for purifying and moistening the incoming air.

The sense of smell of dogs and humans

Such a bone structure is commonly called choanae. The choanae are shaped like bony labyrinths, covered from the inside with sensitive cells. Given this structure, a large tissue surface of the respiratory tract is formed and, accordingly, the air undergoes a large contact surface.

Partially, humidified air is retained in the so-called turbinate. The olfactory nerves and two pairs of branches arising from the cranial nerves and connected by fibers with the nasal mucosa are the basis for the perception of smell.

Scientists have proven that the impressions of any odors can be transmitted through the motor branches of the outgoing nerves. It is also known that the area of ​​the intranasal cavity of a dog approximately corresponds to the total surface of its skin.

A dog can identify a wide variety of smells and scents using its sense of smell. Her sense of smell is the same as a person's vision. The area of ​​the canine brain responsible for smell is 40 times larger than that of humans, and the olfactory receptors range from 125 to 300, depending on the breed. This means that dogs smell thousands of times better than humans.

Knowing about such a sensitive sense of smell, since ancient times people have used dogs to detect various objects and people. Everyone knows these days that dogs can find illegal substances. But that's not all. There are other objects and phenomena that can be detected with the help of a dog, only few people know about them. Let's reveal the secret of what it really is.

Emotions

With different physical and mental conditions in the human body, the level of hormones changes, and dogs can easily determine this with the help of their sensitive nose. They perfectly understand when the owner is sad, afraid or not feeling well. In Western medicine, there is already a term for a therapy dog. Particularly sensitive animals are assigned to people suffering from depression or anxiety disorders in order to help them get rid of these unpleasant phenomena faster.

bedbugs

With the development in recent years of the bus network, train lines and air travel, bedbugs have been able to travel around the world. The meanness of bedbugs lies in the fact that in the dead of night they painlessly bite a person, drink his blood, and then hide in a shelter. It is impossible to find them during daylight hours. In some countries, special services have appeared offering specially trained dogs to detect bed bugs. Dogs sniff things, furniture or the walls of the house and can accurately determine whether bed bugs live there or not. The services of such agencies are quite expensive, because the accuracy of detecting bedbugs by a dog is 96%.

Reagents

Dogs are also good at looking for water-polluting reagents. Animals are trained to detect a wide range of scents from water. They can track the smell if they themselves are in the water, sitting in a boat with the owner, or even just walking along the shore.

bacteria

In 1960, a disease was observed in the United States that struck a huge number of bees. However, in the 1970s, dogs came to the rescue. It was they who could determine by smell the hives with sick bees, which were destroyed so that the disease would not spread further. The thing is that dogs were able to recognize the smell of pathogenic bacteria. Within an hour, an animal can examine more than 100 hives. If a person did the same work, it would take him two whole days. Therefore, the experience of using specially trained dogs is invaluable! Similarly, a dog can be taught to identify fungi and bacteria that cause plant diseases.

Truffles

Most people have heard of truffle mushrooms that grow wild underground. It is impossible to grow them in the garden or in forestries, so the price for them is very high. It is the dogs that smell the truffles and dig them out of the ground. They also use pigs to search for mushrooms, but they themselves are not averse to eating such a delicacy, so they are not suitable for this. Dogs are preferred. But, of course, an animal trained to find truffles costs several thousand dollars.

Diseases

Dogs, as already mentioned, can feel a change in human hormone levels. The same can be said about sugar levels. In developed countries, dogs have been specially trained for the past 10 years to detect epilepsy, cancer, and diabetes in humans. Animals detect a unique smell of tumors, low sugar and hormones. They can predict an epileptic attack in 10-15 minutes, as a result of which the patient can take measures to protect himself during an attack.

As you can see, a dog's sense of smell can benefit not only the animal itself, but also the person. You just need to know how to use it correctly.