Are Dogs Colorblind?

Every animal perceives the world differently, but how and why is this the case?

Vision is almost always the first sense we use to perceive the world around us, but it is incredibly difficult to try to explain what exactly we are seeing. How do you know that the blue you see is the same blue that your friend would see? How would you describe red to someone who has never seen color at all? Imagining vision for animals that aren’t human is even harder—their experiences are even more different than ours, so how can we go about understanding what they see?

What are colors?

Colors are nothing but a happy accident of visible light! Light is a type of

electromagnetic wave An energy wave that does not need a medium to travel

. These are invisible forms of energy which can travel through space, like sunlight from the sun. Two key characteristics describe an electromagnetic wave: the wavelength and the frequency. Electromagnetic waves can be visualized just the same as water waves. Dropping something into water from a great height might produce very fast ripples. The faster the wave moves, the higher its

frequency. The time taken for a wave to reach the same topmost or lowest point in a wave

Waves rise and fall, and the frequency is the time taken either for the wave to reach the same topmost height, or to drop to its lowest point. Some waves are also bigger or longer than others. The size of the wave is its

wavelength. The distance between the topmost or the lowest points of two successive waves.

If there is more distance to travel, the time taken to reach the same height is greater. This is why waves of a higher frequency tend to have a lower wavelength, and vice versa!

Visible light is depicted by the rainbow-colored band right in the middle of this spectrum. These represent all the colors and light that the human eye can perceive. is not just a handy acronym for the colors of the rainbow; each letter represents a specific range of frequency and wavelength! Every single color we see is a mix of these seven colors.

It is interesting to note that this visible light spectrum is only defined for humans. Many insects, particularly bees, can see in ultraviolet, which lies to the right of visible light and is of higher frequency. Mosquitoes, vampire bats, and snakes can see infrared, which lies to the left of the visible light spectrum and is of lower frequency.

Know More: Visible Light Spectrum Wavelength’s Poster

The world of vision is wacky and wonderful, and it is incredible to imagine what the world looks like through the eyes of a bat, bee, cat, or dog!

How do we see colors?

The evolutionary origins of color vision are a bit mysterious, but a few things are clear. Although insects and

vertebrates A group of animals with a spinal cord.

(like birds, mammals, and fish) split very long ago, the way both groups perceive light is surprisingly similar! Insects and vertebrates both possess special proteins called

opsins A light-sensitive protein.

which allow any kind of cell to perceive light by converting it into a small electrical signal to be passed on to the nervous system. Light and shapes are perceived by cells known as rods, and color is perceived by cells known as cones. Both kinds of cells make up the inner surface of the eye where what we see is translated to the brain! Cones are specialized to understand the wavelength of the light which hits the eye. Humans have three kinds of cones, “short,” “medium,” and “long.” Short cones pick up the lowest wavelength, highest frequency light in the blue end of the visible light spectrum. Medium cones pick up the medium wavelength, medium frequency light in the middle, yellow-green section of the spectrum. Long cones detect high wavelength, low frequency, and see red. The three types of cones together cover the entire range of the visible light spectrum.

How do we know dogs are colorblind?

One of the first experiments on dog’s vision, done in 1989, involved making dogs choose. Three dogs were trained with treats to pick out the “brightest” light in a panel of three lights, training them to select the unique light. Then, these lights were changed to different colors. The dogs were not able to pick out the unique light when it was in the red range, suggesting the color vision of dogs ends somewhere before this in the visible light spectrum.

Glossary

Electromagnetic wave: An energy wave that does not need a medium to travel

Frequency: The time taken for a wave to reach the same topmost or lowest point in a wave

Opsin: A light-sensitive protein

Wavelength: The distance between the topmost or the lowest points of two successive waves

Vertebrates: A group of animals with a spinal cord

Flesch Kincaid Grade Level: 7.9

Flesch Kincaid Reading Ease: 66.3

References

https://www.annualreviews.org/doi/abs/10.1146/annurev.ento.46.1.471?casa_token=JyAB5ocs59QAAAAA%3A_gEtgWLQ4QMfsLqYAwyck9R5sI46mzr6d8xhN9wZBsOduLB-C2TZMkoBrseAXrTIKmMPuvsV6V–mg

https://www.sciencedirect.com/science/article/pii/S259023852030521X

https://www.sciencedirect.com/science/article/pii/S0959438899000148

https://www.sciencedirect.com/science/article/abs/pii/S0378111902008454

https://www.nature.com/articles/17383

https://www.cambridge.org/core/journals/visual-neuroscience/article/abs/color-vision-in-the-dog/5A30E35A384D10B6A2B46B01C896D3D5

https://link.springer.com/article/10.3758/s13423-017-1404-7

https://royalsocietypublishing.org/doi/10.1098/rspb.2013.2995

Contributors

Yamini Srikanth: Author

Yamini's (he/they) interests lie in environmental education, science communication and trying to build a better world. When not languishing in front of his laptop, they can be found outside, poking at any insect, bird or plant. They love making science accessible, especially to those who aren't encouraged to pursue it. Yamini hopes that the young women who read Smore love learning from their articles and get just a little bit more excited about science!

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