Are Dogs Colorblind?
The long held myth has been that dogs have a black and white view of the world and are thus utterly colorblind. This has caused many owners of dogs to question, “Will my dog notice at all should I purchase a red toy? Such a strong myth may cause misunderstanding and even affect our treatment of our favorite pets, which may reduce the quality of their playing and training.
However, are dogs colorblind as most people imagine they are? Otherwise, which colors are they able to see? Knowledge of the real visual world of your dog is not merely a scientific interest; it is an essential part of responsible ownership of a pet which can significantly enhance the process of training and of running and even of their security in the complicated world.
This scientifically researched, expert veteran veterinarian ophthalmology-grounded, and evolution-based comprehensive guide will finally put the record straight. We will explore in some depth the intriguing fact about the color vision of dogs, we will discuss anatomical peculiarities of the eyes of dogs and people, and we will give you practical and actionable recommendations concerning how to make the most of the visual experience of your dog. You must prepare a new vision of the world of your canine friend.
Do Dogs Have Colorblindness?
No, dogs are not monochromatic as humans are. Rather, dogs are dichromatic in vision, that is, they have a bias on color spectrum which they can view; however, less than people. They have the same color vision as red-green color blindness in humans, which mainly they can distinguish blue, yellow and gray or dark gray and suffer the difficulty in distinguishing red and green tones. It is so because their retinas can have only two colors-sensing cones as compared to three types of color-sensing cones in most human beings.
The Science Behind Canine Vision: It’s All About Cones
The detailed anatomical study of the eye and the retina of dogs is to be considered to get the definite answer to the question of whether dogs are colorblind or not. The light-sensing tissue of the eye (retina) has specialized cells or rather photoreceptors: rods and cones. Both of these types of cells determine all the aspects of the way an animal perceives the visual world.
Anatomy of the Canine Retina and Photoreceptors:
The biological film in which the light is transformed to electrical signals is the retina. The subject of its composition shows the main preoccupation of an animal:
Rods: These are the cells that are very sensitive to the low light and movement. They work irrespective of color. The dogs have much more rods as compared to humans and thus they are excellent at looking in low light and tracking even minor movement.
Cones: These are the ones that need a brighter light and they are the ones that handle color. The number and the character of cones that a particular animal possesses will define the width of the animal color spectrum.
Dog Vision vs Human Vision: A Tale of Dichromacy
The essence of the difference between dog vision and human vision is the different arrangement of the cones- a biological print of their evolutionary priority:
Human Vision (Trichromatic): the majority of human beings are trichromats, i.e., they possess three kinds of cones: S-cones (short wavelength, sensitive of blue/violet), M-cones (medium wavelength, sensitive of green/yellow), and L-cones (long wavelength, sensitive of red/orange). This three cone system enables us to view the rich and full colour spectrum.
Dichromatic: As is the case with the majority of the canids, they are dichromats. They have just two kind of functional cones which are sensitive to the blue-violet and yellow-green color ranges in the light spectrum. They do not have the cone type that allows them to effectively differentiate the wavelengths that are long, i.e. red and green.
Central Idea: The difference in the human and dog cone systems can be attributed to the dichotomy and the fact that the two different systems have very different visual perceptions. Where human beings were more concerned with detail and color perception (trichromacy), dogs were more concerned with survival, which objects could move and travel in the dark (dichromacy, assisted by the presence of more rods).
What Colors Can Dogs See?
A “black and white” description of the canine visual experience is a gross misrepresentation. If we recognize that dogs do not have complete color blindness, then how would their color range work? Dogs see a full-spectrum of colors; however, those colors are filtered through their visual process.
The Dog’s Color Spectrum Described: Blues, Yellows, and Gray
Think of a rainbow in which the areas for red, orange and green have been compressed and muted to earth tones. At the opposite end of the spectrum — blue and violet — these colors remain vivid, sharp and very noticeable by the dog.
Blue/Violet: These colors are viewed most accurately because they are at the short-wave end of the spectrum. A dog will quickly identify a blue object against a yellow or gray background. To get your dog to find an object immediately, paint it blue.
Yellow/Orange: Medium-wave cones perform reasonably well in terms of seeing yellows and oranges. Dogs will probably see light green as yellow and will have trouble distinguishing between true yellow and green or orange.
Red/Green: This is the “gray area.” Because dogs do not have the medium-long wave differentiation that humans do, can dogs really see red and green? No. Objects colored red appear dull, muddied and brownish-grays — and are usually indistinguishable from natural backgrounds such as dirt, dry leaves, etc. Green usually appears as a slightly lighter version of yellow or a shade of gray — making a green ball nearly invisible when thrown onto green grass.
Environmental Influences on Color Perception: Color Constancy
Humans use color constancy very effectively. It is the ability of the human brain to interpret an object’s color as stable across changing lighting conditions. Dogs, however, rely significantly on the amount of light, and the amount of motion in the environment, to achieve a similar effect with their dichromatic vision.
As an example, if a yellow object is very easy for a dog to see during bright sunlight, the same yellow object will rapidly lose its definition as the light decreases and will eventually become almost indistinguishable based solely upon the amount of light present — rather than the specific wavelengths of light.
Dog Vision’s Core Strengths: Motion, Depth, and Night
Canine eyes developed better characteristics to compensate for their limited color vision, leading to development of extraordinary features important for their survival as predators and guardians.
Amazing Motion Sensing Ability and Sharpness of Vision
Dogs have more rod cells than humans, therefore they can process visual input much faster than humans can. As described above, the speed of processing visual input is measured by the Flicker Fusion Frequency (FFF), the number of times per second that continuous light will flicker before it becomes steady.
Humans: The Flicker Fusion Frequency is about 50-60 Hz.
Dogs: The Flicker Fusion Frequency is up to 70-80 Hz.
Because of this, dogs are able to recognize fast-moving objects better than humans can; an ability important for hunting or catching objects that are moving quickly, such as balls, frisbees, etc. Also, because of the fast Flicker Fusion Frequency, a dog watching a TV will see the individual frames of the TV as separate images if the TV does not have enough frames per second to create a smooth image, so we need to make sure our TVs have at least 85 frames per second. Dogs do not use their sense of sight to tell different shades of red from one another, but instead to recognize movement.
Strong Night Vision: The advantage of Tapetum Lucidum
The best example of how well adapted dogs are to low-light conditions is the Tapetum Lucidum, a reflective layer located immediately behind the retina in a dog’s eye.
How it works: When light enters the eye and strikes the retina, the light that was not absorbed by the photoreceptors reflects off the Tapetum Lucidum and goes through the retina again. Because of this double-absorption, much more light is available to the photoreceptors.
What it looks like: That is why, when you shine a light into a dog’s eyes in the dark (usually green, yellow, or blue), it will look like the dog’s eyes are glowing. The reason for this is that the Tapetum Lucidum is providing the additional light that the photoreceptors need to function properly in the low-light conditions. This is the main reason why dogs have better night vision than humans.
Field of View and Depth Perception
The field of view of a dog differs from that of a human due in large part to their positioning on the head. The positioning of the two eyes of a dog are positioned further apart on the skull, resulting in a greater horizontal angle of view than a human.
- Dogs can see approximately 240 degrees horizontally (this varies depending on the dog breed).
- Humans can see about 180 degrees horizontally.
However, with the increased angle of view, comes the loss of some binocular vision (where each eye views the same visual stimulus). Binocular vision, provides an important aspect of how we perceive depth in our environment. Dogs do experience reduced binocular vision relative to humans, but they use this as one method to assess how far away something is. They also use motion, tilting of their head, and how objects vary in size (closer objects will be larger) as means to determine distances between objects.
Evolutionary Context: Why Did Dogs Evolve This Way?
The visual modifications of the dog eye are not defects; it is an effective survival mechanism that has been successful over the millennium.
It is better to be a Survivor than a Color.
Low-Light Hunting: The domestic dog ancestors were either crepuscular (most active in the dawn and dusk) or nocturnal predators. High quality night vision and tracking motion were also needed in the search and tracking of prey during dark conditions. Color distinction was not in itself a premium characteristic to a prey that hunted a deer or a rabbit, which was mostly a monochrome animal, upon a background that was mostly neutral.
Visual Communication: The majority of the communication in dogs consists of non-verbal camera work (body language, posture, facial expression). It is the rod-heavy, high-FFF system that is used to detect these small, quick movements (a twitch of the tail, a slight change of the ear position) rather than a change in the color of the coat of another dog.
The UV Light Mystery:
Interestingly, there are studies that dogs are capable of seeing in the near-ultraviolet (UV) spectrum of light which is invisible to humans. They may also be able to see markings on snow or urine tracks that are invisible to the human eye, and this may be due to this ability, perhaps based on their heavy retina, which makes them distinguish their visual world even further and give them an added edge in navigation.
Practical Application: Utilizing Dog Color Vision
Now that we are aware of the reality that what will be visible to dogs is reduced to blue and yellow, we can even optimize our contact with them in a scientific manner.
Wise Choice of the Toy to be as visible as possible
Avoid: Red, orange and light green toys and more so on playing outside in a grass or dirt field. These colors are directly mixed with the yellow-brown-grey background of the dog causing frustration.
Selection: Blue and bright yellow are the best colors in which to make the dog toys. A blue ball will be conspicuous on green lawns, red couch or wooden floor. This lessens frustration in fetch games and makes the dog interested in the game.
Good Texture: Due to the limitation of color, it is better to concentrate on toys of different textures, scents, and shapes which are not very important as primary identifiers, but as secondary ones.
Environmental Optimization and Training
Agility Equipment: In case of constructing agility course, it is recommended to use blue or yellow colour in obstacles, tunnels, and contact areas so that they are more visible and clear. This increases the concentration of the dog to work on the task instead of trying to find the obstacle.
Targeting: In complicated targeting practice, a blue target on a neutral floor is used. The difference between the dog color vision system makes the dog perceive the target instantly.
Safety: Reflective strips, vests, or harnesses should be used when walking along the roads, with a blue or yellow coloring. This improves the visibility of the dog to other incoming vehicles (they are trichromats) and their owner can easily see the dog in low light.
