The latest science news about how dogs see
It is known that dogs do not see far, it can be said that their visual acuity, and their ability to see at a distance, is four times less than that of a human being. What a dog sees only at 25 meters, we will notice at 100 meters with the same accuracy. On the other hand, dogs find it very difficult to see close objects. The minimum focal length is 30 cm, which means that it is more difficult for them to focus on an object located at a shorter distance. We can say that they are strictly myopic.
Although in progress science, Some unknowns are not fully disclosed. One of them is how they see dog. There is a great certainty of knowledge about how dogs visually perceive their external environment. In this sense, there are many studies trying to come close to a definitive answer about the ability of this popular animal to distinguish different Colors.
Humans have three types of cone photoreceptor cells: long-wave (red), medium-wave (green), and short-wave (blue), which are the recognizable primary colors. Meanwhile, dogs have only two, which correspond to short-wave and long-wave sensitivities (blue and yellow).
From this data we can conclude that dogs see colors in shades blue and yellowThey are unable to distinguish well between shades of colors such as red and green. In other words, they have dichromatic vision, with two types of color receptor cells that make them see color within two spectrums of light: blue and yellow.
To stir up controversy, some studies provide evidence to suggest that dogs can imagine These colors even without the corresponding cone photoreceptor cells. These studies warn that dogs appear to be more aware of the colors they can perceive because during the test they were able to distinguish between the three primary colors and gray.
It is not known if this is due to the differential density of gray or actual perceived color differences. Other recent studies claim that although they lack a specific UV visual pigment, dogs may have the ability to perceive ultraviolet light.
The truth is that more serious and comparable research is needed to understand how well dogs perceive color and how similar a dog’s perception is to that of humans.
What is true and proven assures us that the dog will be able to distinguish between different shades of blue, yellow and gray; But he could not distinguish green, pink, red or purple. These assertions explain why, for example, a dog TV channel called DogTV prioritizes these colors in its programming.
In addition to being able to identify certain colors, dogs are able to see in the dark. Among the variety containing cells Retina For a dog, in the sensitive membrane of the eye, which would be like the roll of an old camera, there are retinal rods which are the receptors that allow vision with very low light.
At the bottom of the eyeball is a membrane that acts like a mirror, focusing light rays, and increasing the effectiveness of the receptors. This membrane is called tapetum lucidum, which is what makes their eyes shine when we take pictures of our dogs in front of them in the dark. Because they have more rods and tapetums, dogs discern and see up to five times more in the dark than we do.
* Prof. Dr. Juan Enrique Romero @drromerook is a veterinarian. Specialized in university education. Master’s degree in Psychological Immuno-Endocrinology. Former Director of the Hospital Escuela de Animales Pequeños (UNLPam). University professor at various Argentine universities. international speaker.