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THE MENAGERIE AT THE PORCH
ABOUT DOGS

CANINE SCENT

Good dog-Bloodhound is a fine instrument, and to treat it as a precision instrument.
P. H. Wright. The science of smell

These words are for dogs, not humiliating - precision instrument value.

Our live instrument - not the champion of the volume of the olfactory bulbs: the person they occupy a 0.125 cm -3, cat - 0,375, the dog is 1.25, and the horse as much as 5.0 cm3. But the acuteness of smell depends not only on the amount of bulbs, but also on the size of their surface. And it increases the ledges - experts call them getmodelname sinks. In ungulates eight shells, the hedgehog - five, people are just two, and the dog - six major and several additional. As a result, the surface of the olfactory apparatus taxes 15 times more than a person appearing next to her giant.

The structure of the olfactory organs studied well, to still exactly how the dog sniffs, still it is not known. On this account there is only a hypothesis. They are quite complex, and their description may seem boring. And yet, be patient - it's only a few paragraphs.

Inside a dog's nose is always wet - it is covered with liquid, actively absorbing gaseous substances. This fluid captures a very small fraction of the inhaled molecules - the others are in light. However, this dog enough to understand what smells like.

What happens to these molecules? I think that the smell depends on the adsorption properties of substances and olfactory cells distinguish substances for these properties. There is a belief that it is predetermined by the fact that molecules absorbed by the pigment of the olfactory cells, vibrate, causing the pigment changes color. From this point of view, the mechanism of perception of smell similar to the mechanism of color perception. The latest speculation about a dog's nose is that in full of enzymes olfactory cells can go reversible changes of proteins and corresponding electrical signals are transmitted along the nerve fibers.

Still more entangled, if you remember how easily dogs sort odors emit from them. We have the strong smell usually clogs the rest, as they recognize Caproic acid other fatty acids. If the "four-legged devices" to give a fairly common pharmacological drug amphetamine, after half an hour the scent even more aggravated. Acts fenamin long - a few hours. And to the Bloodhound better differentiated, and smell her, if necessary, fed a mixture of amphetamine with a solution of bromine. The proportions and doses of stimulants are not listed for obvious reasons, neither should the fans to experiment.

Smell smell is the same: the sensitivity of a dog's nose increases with increasing number of carbon atoms in the molecule substances, which she was interested. And for all that the dog is not sensitive to floral scents. This well - allergic rhinitis hay it did not happen. This is bad - maybe she doesn't know the smell of roses or lilies of the valley. And actually, what's wrong? Evolution purposely set up her nose at the smell of prey. For irritation of the olfactory cells of her nose enough of a single molecule of butyric acid. To this persistent component sweat it a million times more sensitive person. And the more soaked pursued the animal, the more delicious, from the point of view of our four-legged friend, the smell.

The smells are hard and tender, pleasant and repulsive, they make us happy and annoying. They change the mood and depth of the activities of the body. For example, the fragrance of the hot not only increases salivation - without even noticing, we begin to breathe faster. There are more strange effect - the smell of camphor increases the sensitivity to green light, the smell of ammonia increases the pain. Probably the dog all this a hundred times sharper. She lives in the world of scents; it is inseparable from it - after transection of the olfactory pathways dog usually will not stretch and months.

Bloodhounds are criminals on the trail. Know it all. But not everyone knows that each imprint of the Shoe remains at least 2511 molecule of aliphatic acids, isolated feet and penetrated the soles and seams of the boot. With the city's asphalt these molecules evaporate faster than bordered by grass paths: on the nature of the dog can take a trail through the day after the incident. Side wind carries the smell: dog running by the side of after cornering loses it. Rain generally washes away particles of smell, and when the dog falls into confusion. But the snow interferes with her a little: when the snow is well trained search dog confident on the trail, even if it was covered 12-inch by snow.

But the vision in dogs unimportant. They are generally half-blind man can see when he will approach 300 meters. Often they say that dogs have black and white vision. The end of an absurd delusion (recall, wolf, afraid of red flags) put biologist C. K. Shepeleva. In the Essays of functional properties analyzers wild mammals" ("Science", 1971) it is not only summarized disparate information, but also described his experiments with several species of animals. Ferret Pusa had been tortured by the changing conditions of the experiment that took offense, went to the closet and sat there for ten hours. Nerves in dogs Bugs and Kakashi were stronger, although the experimenter tried to hold them back. For example, the green color that does not "Bang"that gave camphor or Topoleva oils. And all the same Bugs and Cocoa, when needed, was distinguished by a green color from the other four colors of different intensity.

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The menagerie at the porch

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