Most of us are at least vaguely aware that dogs see the world around them differently to how people do, and dogs are often perceived to either be colour blind, or view the world in greyscale. Gaining a deeper understanding of how your dog sees, and the limitations of their vision can be incredibly informative to the dog owner, both in terms of personal interest and also as a training aid. Knowing that your dog can see you, exactly what they can see and how they perceive movement are all, of course, valuable tools for working with your dog and catering to how they interact with the world around them.
Read on to learn all about the vision of dogs, and how to learn to see the world through your dog’s eyes!
Contrary to popular belief, dogs do not view the world in black and white or in greyscale. But dogs do see a much more limited range of colours than people do, and while people can view the whole rainbow colour spectrum from red through orange, yellow, green, blue and indigo to violet, dogs view a much narrower range of colours. The vision scale of the dog is based around creams, whites, blues, purples and greys, providing a much more limited range of colour perception than that of people.
Colour-blindness, a condition that causes some people to see a limited range of light cones (leading to an inability to differentiate between two contrasting colours, most commonly red and green) occurs in around 4% of male humans, and this range of colour vision is similar to that of the dog. Your dog would not be able to tell the difference between a green toy and a red toy, for instance, if the only difference between them was the colour!
The night vision of the dog, or their ability to differentiate between shapes, obstacles and spaces in limited light is actually much keener than that of people. Dogs’ eyes have more rods than those of people, which enable the eyes to process the available light more effectively, as well as having a reflective surface in the area of the eyes that contains the light-sensitive cells, meaning that the eyes of the dog also amplify and magnify the available light. This reflective surface is what causes your dog’s eyes to take on that odd reflective green glow that you might see if you shine a torch on them in the dark, or take a picture of them using a camera with a flash!
Dogs are more adept at detecting movement than people, even from some distance away. Added to their superior night vision, this explains why dogs will sometimes take off in pursuit of something in the dark that their handlers are totally unaware of or unable to see! Detecting movement is key to the vision of the dog, and dogs are much less adept at detecting or focusing on the presence of something that is stationary, or differentiating it from other parts of the landscape. This is why movement is so effective at getting and holding your dog’s attention, as it makes you stand out strongly against the backdrop.
Dogs’ eyes are set more to the sides of their heads than peoples eyes are, meaning that dogs have a much wider field of vision, and are able to see things to their sides and towards their backs whereas humans can only see straight ahead and peripherally. While people have 180 degree vision, in the dog this is nearer to 270 degrees (depending on breed), giving a smaller blind spot to the rear. This allows the dog to process an overall snapshot of everything that is going on around them, and gives them more chance of observing things approaching from behind them, but gives them less depth perception than that of people.
Depth perception is provided by both eyes working together, which happens within the field of vision that is viewed by both eyes. As the field of overlap in the vision of both eyes is smaller for dogs than for people (as their eyes are further apart, providing a wider range of vision) this means that the depth perception of the dog is less accurate than that of people.
Dogs do not have a good eye for detail, or the ability to pick out the finer features of things. This means that dogs can view large obstacles and clear delineations much more clearly than they can view subtleties, and your dog is unable to be likely to pick our specific patterns or markings, such as on their bedding or your furniture. The cones of the eyes provide acuity of vision, and the eye of the dog does not have any area that is 100% cones, unlike people. This means that the detail vision or acuity of the dog is as much as six times poorer than that of people.
Dogs are less sensitive to light and brightness than people are, and can detect brightness and changes in the light (such as sunrise and sunset) about half as proficiently as people. This means that people pick up many more subtle changes in the light and shadows than dogs are able to.
As with people, the senses of the dog work together to present the full picture of the world to them, and allow them to manage it accordingly. Over all, the eyesight of the dog is not as keen as that of people. However the dog’s sense of smell and the incredible range of scent differentiation that the dog is capable of balances this out. While people are generally highly visually-oriented and rely on their eyesight to undertake the main part of their navigation around their world, for dogs, their primary sense is smell, which to a great extent works to balance out the difference between canine and human vision when taken as a complete picture.