How Do Dogs See?

The most obvious answer to this question is: with the eyes. Yet the most common answer usually given by any person is: in black and white. However, it has recently been discovered that this myth is not true. Dogs can see in color, but the range of colors they perceive is less than that of humans. Have you ever noticed that your dog takes longer to find his red toy, especially if he has fallen into the grass? Or that he doesn’t pay attention to the red ball but yes to the blue one? All this is due to their difficulty in distinguishing some colors that we humans recognize without problems. In the following article we will explain how dogs see.

What exactly is sight?

What is known as sight is nothing more than the result of a combination of factors which include: the field of view (the “width” of vision, ie what is seen out of the corner of the eye), the perception of depth ( used to measure distances, and without which we would bump into walls), sharpness (the ability to focus and not see everything out of focus), perception of movement and color differentiation. The combination of these aspects, properly processed by the brain, is what gives rise to sight.

How does canine vision differ from human vision?

The level of peripheral vision and the width of the visual field are determined by the position of the eyes in the head. A dog’s field of view is 240 °, while that of humans is 200 °, which means that these animals have a wider view than ours. Nonetheless, a dog’s peripheral vision is about half that of a human, so they measure distances worse.

Visual acuity (focus) is the aspect that the ophthalmologist measures by showing us the “letters”. This ability in dogs is quite limited compared to humans: a dog can distinguish at 20 feet what a person can distinguish at 25. Therefore its ability to see from a distance is relatively poor, and it is no wonder that the your dog does not distinguish you if you are more than six meters away.

On the other hand, dogs possess an optical structure that is unique to hunting animals. This means that they have a special structure under the retina that works as a mirror and intensifies the amount of light that the animal perceives. For this reason, dogs have excellent night vision and are able to move better in the dark or in low light.

How does color perception work in dogs?

The perception of color (in dogs and humans) is determined by a series of photoreceptors called cones that are found in the retina (the innermost membrane of the eyeball), and which are stimulated in poor lighting conditions.

While in humans the retina is made up exclusively of cones, in dogs these are found only to an extent of 20%, so their vision allows them to pick up only certain wavelengths. This implies that humans can see 3 primary colors (magenta, cyan and yellow) and all their combinations, while dogs can only see two primary colors (cyan and yellow). For this reason the number of their combinations is drastically reduced, and the reds, oranges, purples, browns are lost …

In fact, it has been proven that dogs confuse red with green, just like color blind people, and therefore make it difficult to recognize red objects. Especially if a red object is on a green background (or a green one on the red background). So when you go to buy toys for your dog, choose blue or yellow ones, so that he can distinguish them better.