Dog-lovers don’t generally give too much thought to dog vision. We are used to thinking that dogs see in black and white (wrong!) and that their sense of smell and hearing is more important than their vision.
But what do dogs actually see? 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 colour blindness.
That just means that the red-sensing and green-sensing light wave cells in a dog’s eyes are the same. Thus, they find it difficult to tell red and green apart. So, dogs’ spectrum vision skips the red and green section altogether, in a way, and contains a lot of murky yellows in the 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.
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 dogs have over you in the vision department, is that they can see some ultraviolet rays.
That means they can see some light waves close to the ‘black light’ patterns without a special lamp. Maybe they can even see through different layers of a painting. It seems that dogs can smell cancer, so maybe they should start identifying forgeries, too?
The night sky must be a treat for dogs. They should be able to see through all that light pollution and therefore see a lot more stars than us. Although the stars must probably be pretty blurry to them.
On the downside (for us), dogs can see pee-stains, dandruff, and lint more clearly that humans can.
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 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 oral directions, as we listen to (or ignore) the wise voice of GPS.
But for dogs, 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.
On top of the ultraviolet revelation, it is clear that dogs are pretty damn sci-fi.
When dogs wander the earth, they sniff trees, the ground, and the air to position themselves. But they can also ‘smell’ the past: they can smell not just the latest dog to pee on that bush, but even several who might have been there before him.
And by smelling the air, they might even be able to smell what’s about to happen, for instance, what dog is just around the corner, or that you’re headed to the vet clinic!
Dogs are constantly updating their internal, trans-temporal map of the world. No wonder they’re so excited when they get taken out for a walk!
There’s more to the universe than meets a dog’s eye.