Dogs from ancient times are our friends and livein families. It's no surprise that people are so interested in the details of how their body works and how it functions, what is the psychology of the four-legged pet. Scientists, veterinarians, zoopsychologists have been studying this for a long time.
As well as at the person, at home pupils visualfunction provides a special organ - the eye. He is a pair, all animals have two. The basic structure of the organs of vision is the same in humans and dogs. Nevertheless, there are differences.
How do dogs see the day?
Daytime vision is generally not better thanhuman. But for a predator it does not play a big role. The structure of their eyes, as well as of the whole organism, is maximally adapted for other purposes, conditioned by their way of life.
Features of seeing dogs in color - one of themain issues that worried people. Not so long ago it was found that dogs distinguish colors, and their vision is not black and white at all, as was previously thought. However, it is not the same as ours. It is known that the eye has special receptor cells, which have different shapes, so-called "cones" and "sticks." The former are responsible for the perception of color, the latter for acuity and night vision. The cones are of three types: perceiving the red-orange range of colors, yellow-green and blue-violet. Dogs have fewer of these cells as a whole, the first variety is completely absent. In this regard, the difference between red and yellow-green, these animals do not perceive.
By the way, the field of view in dogs is elongated, oval(in people - round), and the axes of the eyes are not parallel to each other, and diverge at an angle of about 20 degrees. This greatly expands the pet's review. Of course, in rocks with a short muzzle, this indicator approaches that of a person.
An animal this refers to the transitional betweenday and night, therefore, should have excellent eyesight in any light. As already mentioned, a large number of rods determines the benefits of daylight, but it also has value in the case of a lack of light. There is one more point: in dogs behind a layer of rods and cones there is another layer, called tapetum (Tapetum), which consists of a retro-reflective pigment. Due to the fact that almost all the light falling into the eyes is perceived by the cells, the night vision of dogs is 3-4 times better than the human.
Of course, what you know now about howsee dogs, can hardly affect your choice of pet for the family. There are no natural differences in color and light perception. The genetic predisposition of this or that breed exists only for various diseases of the organs of sight.
Picking an adequate for your family pet,of course, it is worthwhile to rely on these data as well as on information about other inclinations to diseases. But first of all you should make a choice of a dog for the house according to the purpose for which it was taken, its exterior features and its capabilities, including financial ones.</ p>