This is a question that any person living with a dog sooner or later arise. One wonders if his way of thinking is like ours, if you only see the colors or shades of gray, ending up thinking that what the dog is a world in black and white, filled with a gray film of the era. In fact, to understand how they see the dogs, we must From the structure of the retina, which is formed (as in all mammals) with two cells: the cones , working in conditions that allow full light to distinguish colors, and rods , most effective to decrease the brightness, to distinguish moving images. However, unlike humans, dogs have only two types of cones (instead of three), which results in their having an effect similar to color blindness, denying them the opportunity to recognize the green and red. In particular, their retina is able to select the blue, purple and yellow, but can not distinguish between green, yellow, orange and red, making also difficult to distinguish between green and gray. Even the visual acuity of a dog - or the ability to distinguish details - is less than that in humans (about 50%) and the same goes for depth perception of objects. Their eyes, in fact, being positioned more laterally than those of man, so allow a broader view, but the amplitude at the expense of the area of \u200b\u200boverlapping images, which is essential for the perception of depth. It must be said that the close position of the eyes gives rise to a kind of vision binocular which is typical of predators (allows superposition vision of both eyes and then greater definition of depth) as the man (the eyes are set straight forward) and dog (adjusted to an angle of 20 degrees), while in the natural prey (eg rabbits) the eyes are very spaced in order to extend the range of vision and more easily identify the danger. This is where the view of the dog excels (as well as that of the cat) is the vision of "night" means the corneas and large pupils are able to focus the present and reflect little light on the retina, thus amplifying the light beam (the which also explains why their eyes glitter in the dark). So, rather than the color, brightness, and are motion to allow the eyes of the dog to identify objects, but more importantly is to understand that certain behaviors of the dog are often dictated not by a reaction to "view" of something, but the perception of a movement, the sound of a voice or a smell, this is because, unlike man, the dog is more responsive to the senses such as smell and hearing that from view. In short, the dog is not a world of faded black and white, but is a vivid world, made up of perceptions and reactions that take place continuously on guard their senses and keep alive his attention to his surroundings.
