Most of us have been told or heard at some point in our life that dogs are colourblind, but is this actually true? Over time science has disproven this thought, but dogs still don’t see the world the same as we do. So what colours can they actually see and why is their vision like this?
What is Colour Blindness?
Colour blindness, in humans, is a condition that affects a person’s ability to perceive colour correctly. There are generally two types of colour blindness, red-green and blue yellow. Essentially a person with one of these types is unable to distinguish between these two colours.
Why does this happen? A regular human eye that doesn’t suffer from colour blindness will contain three receptors also known as cones, which allow us to see the full spectrum of colours. This is why we are known to have trichromatic vision.For those with a form of colour blindness, they typically only have two of these cones.
Are Dogs Colour Blind?
While they may not see the entire colour spectrum like we do, this doesn’t mean that dogs can’t actually see colour, just that the colours they perceive may be different to us.
A dog has what is known as yellow-blue dichromatic vision. This means, when comparing their vision to the two types of human colour blindness, a dog sees colours similar to how a person with red-green colour blindness would perceive colours. This is caused by the fact that a dog’s eyes are actually similar to those who are colour blind in that they only have two of these cones. As a result, dogs have what is called yellow-blue dichromatic vision.
Why Did We Think Dogs Saw in Black and White?
While science has now disproven the theory that dog’s can only see in black and white, where did this train of thought even come from? It is believed that back in 1937, the founder of National Dog Week, Will Judy, wrote in a training manual that it was likely dogs could only see in black and grey. Fast forward to the 1960s and researchers further ingrained this theory by suggesting that primates were the only animals that could actually see colours.
However, in 2013, Russian researcheRs decided to challenge this thought and through a series of experiments were able to determine that dogs could actually distinguish between the colours of yellow and blue.
They began their experiments by wanting to test whether a dog could actually tell the difference between two different colours or between the degrees of brightness in the colours. They placed four different coloured pieces of paper - light yellow, dark yellow, light blue and dark blue - on feed boxes, putting meat in the box with the dark yellow paper. With this set up, they trained the dogs to associate dark yellow paper with a treat. From there, they tried placing dark blue paper on one box and light yellow paper on another, theorising that if the dog went to the box with the dark blue paper it was because they simply associated the darker shade with the food. However the dogs repeatedly keep going to the box with the light yellow paper which demonstrated to the scientists that it was actually the colour they were associating with food and not just the brightness level of the shade.
What Colours Can Dogs See?
For pooches, the colours of yellow and blue are dominant in their vision and are the most vibrant for them. This means though that anything blue, blue-green or violent will just look various shades of blue to them, anything red and green based may appear more of a brownish-grey and anything orange, yellow or green may all appear a yellow colour to our furry friends. In general, dogs just cannot perceive the vibrancy of colours the same as we can. This also means that dog’s are not able to perceive small changes in a colour’s shade or brightness like we are able to.
It’s because of this that you may notice that at dog agility competitions they use blue and yellow equipment. Many organisations have also actually put rules in place around ensuring any landing or contact surfaces are yellow or blue to make it easier for our four legged friends to see.
If you are play fetch with your pooch with a yellow or orange ball on the green grass, they will actually use their sense of smell to help find and identify their ball rather than looking for the colour of it. If you’re looking to get your dog more engaged in playtime, try buying toys for them that are either blue or yellow in colour, as these will stand out more to them. This may also by why your dog loves that yellow tennis ball so much.
What Else Is Different About Their Eyes?
As well as seeing colours a little bit differently to us, there are also some other things that are different between canine and human vision. Dogs tend to more near-sighted than us, meaning that an object in the distance that appears clear to you may actually be blurry to your pet.
There are however some advantages they have over us when it comes to eye sight. A dog’s eyes sit further to the side of their head than us which means they have a better range of peripheral vision than we do. However this does affect their depth perception, which is not as accurate as ours is.
While they may only have two receptors in their eyes, dogs actually have more rod cells within their retina. These rods are used for detecting motion and light, and with more of them, our four legged friends can pick up smaller movements at greater distances. This combined with their reflective cells, which gives them those ‘shiny eyes’ in the dark, also allows them to see better in low light situations than us.
Are All Dogs Colourblind?
Currently, there has not been a lot of research into the question of whether all breeds have the same type of vision when it comes to colour. While researchers are currently doubtful that any breeds would have the same trichromatic vision as we do, it seems likely that, just as humans have varying eyesight, that some breeds may have sharper and cleaner vision than others
Do They Hear and Smell The Same As Us?
While they may not be able to see colours as well as us, they make up for it with their other senses, particularly with their hearing and sense of smell.
A dog can hear a much wider range of frequencies than we can, especially those at a higher pitch. In fact, they can hear frequencies that we will never be able to.
Then there’s their sense of smell, which is almost even better than their hearing. In fact their specialised sensory cells, called the olfactory sensory neurons, are 10,000 times more powerful than ours, if not more. Where humans have six million of these receptors, a dog has 300 million. They can also analyse a smell much better than we can and so while we may see more vivd pictures, the things your dog can ‘see’ and learn through smell is more than we will ever be able to imagine.