Introduction
Dogs see the world differently than humans when it comes to color. While humans have trichromatic vision and can distinguish between red, green, and blue light, dogs have dichromatic vision and process colors differently. Dogs primarily see shades of blue, yellow, and gray instead of the full spectrum of colors. This is due to differences in the retina of canine eyes. Some colors that appear vibrant to humans may seem dull or even invisible to dogs. On the other hand, certain shades are more intense for dogs. Understanding dog vision provides insight on how to train dogs through use of color and meet their visual needs.
Dog Vision
Dogs have a very different visual system compared to humans. While humans are trichromats and can see a wide range of colors, dogs are dichromats and have limited color vision (VCA Animal Hospitals). Dogs only have two types of color receptors (cones) in their eyes, which allows them to see blue and yellow but makes it difficult to distinguish between red and green. This is why dogs are considered “red-green color blind”.
In terms of visual acuity, dogs see 20/75 vision or worse, compared to 20/20 vision in humans (BC SPCA). This means dogs see objects less sharply and in less detail. However, dogs have a wider field of view spanning 240 degrees compared to 180 degrees in humans. They also excel at detecting movement thanks to a high concentration of rod receptors in their eyes.
Overall, while human vision prioritizes color and detail, dog vision prioritizes detecting motion and luminance changes. This allowed dogs as hunters to more easily spot prey and threats in their environment. So dog vision and human vision are adapted to different purposes.
Color Perception
Dogs see fewer colors than humans due to fewer cone receptors. Human eyes have three types of cone cells that allow us to see combinations of red, green and blue light. This gives us trichromatic vision and the ability to see millions of colors. Dogs, on the other hand, only have two types of cone cells and can only discern blue and yellow light. This is called dichromatic vision. It’s similar to red-green color blindness in humans, where certain shades get mixed up. With just two cone types, dogs can only see about 10,000 different colors, while humans can detect over 1 million.
According to the American Kennel Club, “Scientists believe that a dog’s color vision is akin to a human who has red-green color blindness, though there are still shades of color they can see and shadows they can detect” (source). So while not completely colorblind, dogs do miss out on some of the color variations that humans readily perceive.
Bright Colors
Research shows that dogs see bright colors like yellow and green more vibrantly than humans do. This is because dogs have a higher concentration of rod cells in their eyes compared to humans, which makes them more sensitive to brightness and motion ([1]). Rod cells play a key role in peripheral vision and night vision.
Yellow in particular is easy for dogs to distinguish, appearing brighter due to their retinal cone cells being most sensitive to blues and yellows ([2]). Green also stands out more for dogs compared to red hues. This may explain why many dog toys and training tools utilize bright green or yellow.
While dogs don’t see colors as vividly as humans, their vision is optimized for detecting movement and brightness. So bright colors like yellow command more of their visual attention compared to darker or more muted shades.
Dark Colors
Dogs have more trouble distinguishing dark colors like blue and purple compared to brighter colors. This is because dogs only have two types of color receptors, unlike humans who have three. The two color receptors allow dogs to see blue and yellow, but they struggle with variations of darker blues and purples.
A study published in the Proceedings of the National Academy of Sciences compared how dogs and humans perceive color. The researchers concluded that dogs see the world in shades of blues, yellows and grays. So while dogs can distinguish between blue and yellow objects, their worldview consists mainly of different shades of gray.
This is why toys and objects that are very dark blue or purple may all look similar to a dog. Bright blues are easier for dogs to distinguish than dark navies or purples. So if you want your dog to easily identify their toys, choose brighter shades of blue rather than very deep dark blues.
Red & Green
Dogs have limited ability to detect red and green. According to research, dogs see the world in shades of blue and yellow. This is because they only have two types of color receptors in their eyes, whereas humans have three. The receptors dogs lack are the ones that detect red and green light.
So while dogs can still see red and green, these colors appear more muted and dull to them. Red may look dark brown or gray to a dog, while green probably appears a faded yellow or beige. This means red and green objects don’t stand out for dogs the same way they do for humans.
Some studies indicate that dogs see red and green as a similar color. So red and green toys or objects may be indistinguishable to them. This is why dog toys often use highly saturated shades of blue or yellow, since these colors are more visible to dogs.
In summary, dogs have limited red-green perception compared to humans. Red and green likely appear dull or faint, and certain shades may look identical to dogs. So these colors won’t grab a dog’s attention or be easily detected unless very bright.
Behavioral Response
Research shows that dogs do have behavioral responses to different colors. According to a study published in the Journal of Animal and Veterinary Sciences, dogs tend to be more stimulated and excited by warm colors like red, yellow, and orange. Cooler colors like blue, green, and violet have more of a calming effect (Effect of Color on Animal Behavior, https://www.arcjournals.org/journal-of-animal-and-veterinary-sciences/volume-3-issue-3/2).
This is likely because dogs have more rod cells than cone cells in their eyes, making them more sensitive to differences in brightness than hue. Very bright colors seem to get dogs riled up and wanting to play. Dark or muted shades don’t elicit the same reaction. So a bright red ball is more exciting for a game of fetch than a dark green one.
Dogs also rely more on body language and smell than visual cues. So while they can detect differences in color, their behavioral response has more to do with the context, movement, and scent associated with the color than the actual hue.
Using Color
When using color around dogs, it’s important to consider their vision and color perception. Unlike humans, dogs see limited color and are essentially red-green color blind [1]. They primarily see shades of blue, yellow, and gray. This means that colors on the red and green spectrum can appear more muted or dull to dogs.
Since dogs see yellows and blues more vibrantly, using these colors in toys, accessories, or decor can help capture their attention and interest. However, very bright colors close to a dog’s face should be avoided, as the intensity can be startling or overwhelming for them. Darker, more muted shades of any color are gentler on a dog’s eyes.
Overall, factoring in a dog’s unique vision and responding accordingly with color choices can make environments more visually stimulating and comfortable for them.
Genetics
A dog’s genetics play an important role in their vision and ability to perceive color. Certain breeds are predisposed to inherited eye diseases and conditions that can affect vision and color perception. According to the National Center for Biotechnology Information, primary or hereditary cataracts are common in dogs and a leading cause of blindness, with cases reported in as many as 97 breeds [1]. All About Vision notes several genetic eye diseases in dogs including progressive retinal atrophy, collie eye anomaly, and retinal dysplasia [2]. These diseases can lead to vision loss and impact a dog’s ability to perceive color normally.
Certain breeds are more susceptible to genetic vision issues based on their genetics. For example, collies are prone to collie eye anomaly, while Labradors and poodles are at risk for progressive retinal atrophy. Responsible breeders screen for genetic eye diseases to reduce their prevalence. But even with screening, genetic mutations can arise and be passed down. Overall, a dog’s genetics play a key role in the health and functionality of their vision and color perception.
Conclusion
In summary, research shows that dogs see color differently than humans. While they may not distinguish between red and green as easily, dogs are able to see shades of blue and yellow. Their vision also allows them to detect brightness and contrast more readily than humans. This means dogs may respond strongly to colors like yellow or neon shades, which appear brighter to them.
The key takeaways for dog owners are:
- Dogs have fewer color receptors, so they see a more limited color spectrum.
- Bright, neon colors will stand out more to dogs.
- Dogs see better in low light than humans, thanks to a reflective layer behind their retina.
- Red and green may be hard for dogs to differentiate.
- Colorful toys and objects can provide mental stimulation for dogs.
- A dog’s genetics and breed will impact their vision and color perception.
By understanding how dogs experience color, owners can choose appropriate toys, make training easier with high contrast objects, and visually enrich their pet’s world. While a dog may not admire a rainbow the way a human does, their unique perspective on color still enriches their lives.