Until recently, it was believed that dogs are color blind and see the world in black and white. However, recent research by scientists has shown a different picture: dogs still see colors, but they do it differently than humans.
Visual experiment
A common misconception about canine vision has been easily refuted by scientists. They put various treats in sealed boxes and marked each box with different colored sheets. The most preferred food, raw meat, was marked in dark yellow. As a result, the experimental dogs were able to easily match their preferred food and color. And even after the researchers replaced the dark yellow leaf with a bright yellow, wanting to know if the dogs were guided by the color itself or by its brightness, the animals still stubbornly walked to the right box in anticipation of a treat.
Varieties of cones
In general, the structure of the human eye and the dog's eye is quite similar. Only the varieties and the ratio of rods and cones differ. Cones are a type of photoreceptor located on the retina of the eye. There are three types of them in humans, and each is responsible for its own range of perceived color. Some cones are sensitive to orange and red, others are sensitive to green and yellow, and still others are sensitive to violet, cyan and blue. Dogs do not have cones that sense red. Dogs' vision is similar to that of color-blind people: they cannot tell the difference between green and red, orange and yellow.
50 shades of grey
But dogs are much better than their owners at distinguishing shades of gray. The reason for this lies in the fact that dogs have more rods on the retina of the eye, which are also photoreceptors. Moreover, they are much more sensitive in comparison with human ones. This helps the dogs see better against the dark ground.
Day and night vision
People see better during the day than at night. In dogs, the opposite is true. In humans, in the center of the retina is the so-called macula - the area in which the maximum concentration of cones is observed, while the rods are on the periphery. The maximum amount of light falls on the macula, and this provides people with visual acuity. In dogs, the macula is absent. Contrary to popular belief, they see much worse than people during the day. On average, human vision in daylight is three times sharper than a dog's. In addition, dogs poorly see near: objects that are at a distance of one and a half meters, they blur. But at dusk, dogs are able to give odds to people. Due to the large number of rods on the retina, they are perfectly oriented at this time of day. Also, the dogs very accurately calculate the distance to the object of interest.
