During walks with our dog, we are amazed at how acute her vision is in the dark. She is a relatively old Newfoundland and we aren’t sure that she can see that great in the daylight. However, when in the woods late in the evening, she always leads and drags us to places where we don’t feel quite comfortable.
So it got us wondering, can dogs see in the dark? We all know that cats excel at the nocturnal vision thing, but what about a dog? In this article you’ll learn how dogs can see in the dark, are dogs color blind, and why dogs have great night vision.
Table of Contents
- What does it look like when a dog sees in the dark?
- What color does a dog see?
- How can dogs see better than humans in the dark?
What does it look like when a dog sees in the dark?
What is it about a dogs eye that is different than ours? There are several studies on this topic. Science Daily for example, states that dogs “can probably see in a light five times dimmer” than humans can. From a 2017 article posted in ResearchGate from Psychonomic Bulletin & Review, a dogs eye is good in both daylight and low light. However, the retina of a dogs eye is “largely comprised of rod photoreceptor cells, which are extremely helpful in dim light“. It goes on further to say that “Only 3% of retinal cells in dogs are cone photoreceptor cells, which are primarily responsible for color vision“. What this tells us is that a dogs eye is ideal for night vision or seeing in dim light. What a dogs eye is not good at is color vision. So it’s true that dogs see color, but not nearly as well as the human eye does. This is because the human eye has 3 different types of cone photoreceptors for red, blue, and green light. A dogs eye has only 2 cone photoreceptors for blue and red/green light. Some older research suggests that a dogs eye can discern red, green, and blue and that they can even perceive ultraviolet light that a human eye can’t.
Another attribute that helps with a dogs eye night vision is the tapetum lucidum. The name tapetum lucidum is Latin and means “bright tapestry”. It is a layer at the far end of the eyeball, just beside the retina. This is a layer of reflective tissue found in vertebrates but not people. The Psychonomic Bulletin & Review article further discusses the tapetum lucidum. That it offers “light sensitive retinal cells an additional opportunity for photon-photoreceptor stimulation by reflecting light“. This means that light that enters a dogs eye via the retina is reflected back and passes through a second time. This gives a dogs eye more visual sensitivity in low light. It does mean that a dogs eye is slightly less able to discern details in the dark because the light is scattered a bit in the dogs eye by the tapetum lucidum. This is also why when you take your pups picture under lower light conditions, their eyes almost seem to glow or are bright red. That’s because the tapetum lucidum is reflecting back the light.
What color does a dog see?
A common myth is that dogs are color blind. Since dog eyes only have 3% of their retinal cells are cone photoreceptor cells, they don’t see color as well as we do, but dog eyes can discern colors. Yes, despite all the old jokes that dogs only see grey and that’s why they can’t drive a car (because the traffic lights would look grey), dogs see color. A Royal Society Open Science study from 2017 tested if a dogs eye has red-green color blindness. The used images of cats and other stimuli to test their hypothesis. They were able to confirm that indeed a dogs eye is red-green color blind. Some people also are also red-green color blind. This condition is called deuteranopia per Healthline. This is a genetic deficiency with the cones in the person’s eye. This red-green color blindness in people is similar to dog vision in that their color vision is much less than a normal humans eye.
Do not underestimate dogs’ abilities though. A dogs eye may not be as good at seeing color as we do, but make no mistake, dogs see color. The unique design of a dogs eye means that dogs can see in the conditions that humans would describe as pitch black. This is why our dog bravely drags us through the darkest parts of the woods where we wouldn’t go on our own. But how do dogs do that?
How can dogs see better than humans in the dark?
As we’ve discussed, the way a dogs eyes are designed makes them better at seeing in the dark than us. Dogs’ eyes are well adapted to gather and use the tiniest amount of light available. This means they can’t see as clearly or discern as many different colors. So how can dogs see in the dark better than us?
- Tapetum lucidum is the largest contributor. The tapetum lucidum as we’ve discussed reflects the light that has passed through the retina back to it, so it receives more light. Unfortunately, this also means that the light gets scattered and dogs have lower acuity than we do. Think about drawing with light pencil strokes. If you’d draw over the existing image again, it would be easier to see, yet, might get distorted. This is why dogs visual acuity (ability to see detail) isn’t as good in dim light, yet it’s still better than that of cats.
- Large pupils is also a trait that lets your dog enjoy better night vision than us humans. The size matters because the larger the iris is, the more light is let into your dogs eye. For example, if you want to get a great photo, a larger lens on your camera would produce better pictures.
- More rods in the central part of the dog’s retina. As we’ve discussed, it is the cone cells in the retina that are useful in color discrimination and rod cells are for vision in lower light. The human retina consists of mostly rods, hence, we are good with colors, but not so good at night vision. Since only 97% of a dogs retina is made of rod cells, this gives them a huge advantage in seeing in the dark over us.
Besides these, we’re sure there are more minor adaptations that make the eye of a dog superior in low light conditions when compared to human eyes. Don’t feel sad though, our visual acuity is significantly better. Just as we are better with colors and our binocular vision and our the depth perception is way superior to that of dogs.
In summary, the answer to the question can dogs see in the dark is an absolute yes. And they are way better at it than us humans. Further, they aren’t color blind as many myths and memes portray. We could say that when it comes to vision, dogs are somewhere between humans and cats. Not only in the ability to see in the dark, but in other aspects as well.
You now understand how your four legged fur baby’s eyes work and how they are superior to ours in one way, but not as good in others. This will help you understand better why your dog behaves the way they do in reaction to different visual stimuli under different light conditions. This will go a long way towards a happy life for you and your dog. And keeping your Pet Happy is what we all want.