Your four-legged friend’s super sense is certainly its nose. When it comes to a dog’s sense of smell, few other pets (such as rodents and grazing animals like cows) surpass them. Less is known about the vision of our furry friends, and there are misconceptions and outdated teachings circulating. It’s especially interesting to consider the environment through a dog’s eyes. Here, you’ll learn how your furry friend visually perceives the world around them.
How is a dog’s eye structured?
How your dog perceives optical impressions differs greatly from your own vision. This is due to anatomical differences in the structure of dog and human eyes, as well as their position in relation to skull shape. The main differences are as follows:
- More rods: Rods are light-sensitive cells in the eye, simplistically explaining, which enable the perception of light and dark. Dogs have more rods than humans, allowing them to see better in low light conditions.
- Fewer color receptors: For color perception, there’s a second type of sensory cells in the eye called cones. These are equipped with receptors to detect various colors. Dogs only have two types of cones, while humans have three.
- Reflective layer: In the retinal area of the dog’s eye, there’s the so-called tapetum lucidum. This mirror-like structure enhances incoming light.
- Lens shape: Dog lenses are up to four times larger than human lenses, and their pupils dilate more accordingly. This allows more light to reach the retina.
Seeing the world in color: Do dogs see in black and white?
The notion that dogs don’t see colors and perceive their surroundings as monochromatic was a widespread belief in the past. However, there are now new insights into the color vision of quadrupeds.
The brain processes the received stimuli from different receptors into differentiated color impressions. In a dog’s eye, there are only two types of color receptors on the cones (the nerve cells for color perception), namely those for yellow and blue. Dogs are, in technical terms, dichromats. With this organic setup, they can see 10,000 different colors, but only shades of yellow, blue, and gray. This is a much smaller color spectrum than that of humans, who have additional red color receptors.
As a result: When buying dog toys for fetching, you should choose colors other than red. Red dog balls in green grass are hard for your furry friend to distinguish.
Furthermore, dogs can see light in the UV spectrum and perceive things like urine traces or fluorescent objects in daylight.
Night vision mode: Can dogs see in the dark?
Wolves, the wild ancestors of dogs, are crepuscular animals that hunt at dawn and before the onset of darkness. To be able to recognize their prey in twilight, good low-light vision is essential.
In fact, dogs see about five times brighter than diurnal humans in adverse lighting conditions due to the larger number of rods in their eyes. Additionally, the aforementioned tapetum lucidum amplifies incoming light. However, in complete darkness, even a dog cannot see anything.
360-degree perspective: How far does a dog’s field of view reach?
Dogs’ eyes are not forward-facing (like humans) or sideways (like rabbits), but are positioned slightly laterally on the head and slightly further apart than in bipeds.
Moreover, thanks to strong musculature, their eyes are quite movable. This results in a much larger field of view for dogs compared to their owners. It’s about 240 degrees. Therefore, dogs even register movements happening behind them. With only a 180-degree field of view, humans have significantly lower peripheral vision.
However, the field of view varies slightly depending on the breed of dog. This is due to the different shapes of their heads: In dogs with short snouts (such as pugs), the eyes are positioned further forward than in animals with long snouts.
The position of the eyes, in turn, affects spatial vision. Depth perception and the ability to perceive three-dimensional space result from the overlap of the visual fields of both eyes. The more forward-facing the eyes are, the better the spatial vision, but the less panoramic. This means that dogs with long snouts, for example, estimate distances less accurately than counterparts with shorter skulls. Compared to humans, their long-range vision is four times weaker – technically speaking, dogs are nearsighted.
Frame rate: How “fast” do dogs see?
The term frame rate is common in the context of graphics cards or monitors. Eyes also have a frame rate, expressed in fps (frames per second), indicating how many individual frames are processed per second. The perception of the human eye is about 60 frames per second. A dog, however, sees up to 80 frames per second. This means that dogs perceive fast movements much more precisely. This is a significant advantage, for example, when catching a ball or a frisbee.
Conclusion: Dogs have a different perspective on the world
By the way, your furry friend is ahead of you even in selective seeing: Dogs focus well on relevant things and filter out uninteresting ones. A major challenge in training companion dogs is therefore teaching them the importance of seemingly insignificant objects (such as curbs).
The visual perception of dogs and humans differs in many ways: While dogs look faster, “brighter,” and more comprehensively, you as a human have advantages in color and spatial perception. When you combine your visual abilities, you and your furry friend form a team with keen eyesight.
