Dog-lovers don’t generally give too much thought to dog vision. We used to think that dogs see in black and white (wrong!) and we know that their sense of smell and hearing is more important than their vision. And we even have boffins trying to find out whether dogs dream.
But dog vision? It’s always been a bit of a mystery. Until now. One new website promises to show exactly how a dog might see any image you show it, and scientists are learning more about a dog’s visual sense every day.
Dog vision and colour
First of all, let’s dispel the greatest dog myth of all: that dogs only see in black and white. Not true. Dogs are ‘colour blind’ in a similar way to people who have red-green colourblindness.
That means that the same cells in a dog’s eye process red and green light waves. Thus they find it difficult to tell red and green apart. So, dogs’ vision skips the red and green section altogether, in a way, and contains a lot of murky yellows in place of all those shades.
The clarity of dog vision
In addition to their colour blindness, dogs’ vision is less clear than humans. They have lower ‘visual acuity.’
Everything looks a bit blurry to your dog, which means that they might find it a bit difficult to notice a very small object at a distance or that tiny piece of treat that you dropped at your feet and they seem to have lost track of. However, when the light is dim, she may be able to see a bit better than you. This is why it is safest to keep your biscuit tin in a brightly-lit area if you don’t want to fall victim to furry crimes in the night.
The distance of dog vision
Dogs are near-sighted. Experts say dogs have 20/75 vision. That means that a dog can see something from 20 feet away at the same level of clarity as a human with ‘normal’ 20/20 vision would see it at 75 feet away.
So when she loses track of that ball that you threw as hard as you could, don’t blame your dog. Blame Specsavers.
Dog vision and ultraviolet light
One big advantage your dog has over you in the vision department, especially if you like to take her to raves (which we suggest you don’t: the loud music is really too much for your dog!), is that she can see some ultraviolet rays.
That means she can see some light waves close to the ‘black light’ patterns without a special lamp. Maybe she can even see through different layers of a painting. They say that dogs can smell cancer, so maybe they should start identifying forgeries, too?
The night sky must be a treat for your dog. She should be able to see through all that light pollution to a lot more stars than us. Although the stars must probably be pretty blurry to her.
On the downside, dogs can see pee-stains, dandruff, and lint more clearly that humans can. What they plan to do with all this information is not known (probably look for treats).
Your dog’s vision and farts
A few years back, researchers at the Rochester Institute of Technology revealed that dogs could see their own farts. The scientists supposedly trapped dog farts in jars. They said that they demonstrated that the test subjects' brains showed the same activity when they saw the jar as when they smelled their gas.
But it was soon revealed to all be a hoax. The researchers didn't even exist. Dogs can’t see their own (or anybody else’s) farts.
Your dog’s vision and the dog nose
On a conscious level, humans use vision to orientate themselves in the world. We look around us, spot visual cues, compare what we see to a map of the area, etc.
Of course, we also use sound, although it’s often subtle. The reflections of sound waves (echoes) from the walls let us know how close we are to stuff, where somebody we can’t see is talking to us from, and so on. And more than ever, we use aural directions, as we listen to (or ignore) the wise voice of GPS.
But for a dog, their nose stands in for their vision when they are mapping the world around them. And it doesn’t just work in three dimensions like our human visual maps. A dog’s nasal map transcends time, tracing the past, and triangulating the future!
On top of the ultraviolet revelation, it is clear that dogs are pretty damn sci-fi.
When your dog wanders the earth, she sniffs trees, the ground, and the air to position herself. But she can also ‘smell’ the past, just like when she looks through layers of a painting. She can smell not just the latest dog to pee on that bush, but several who were there before her.
And by smelling the air, she can sniff out something of what’s about to happen. What dog is around the corner. Maybe even that you just hung a right towards her vet’s surgery.
Your dog is constantly updating her internal, trans-temporal map of the world. No wonder she’s so excited when you take her out.
There’s more to the universe than meets a dog’s eye.
By Published on 18 Jan 2019