The world is awash with colour- from the garden full of different flowers to the rainbow. Every living being has the different colour vision to see the world. Humans see the detailed and colourful version while dogs, mice have the colour-less life with exception of grey or blue colour. Birds and bees have the much superior vision and they can see much clearer than any other animal. Even bulls are colour-blind and they will charge at any piece of moving cloth, red or not.

Have you ever wondered how your horse sees this world?

Can your horse appreciate your catchy efforts?

It is difficult to determine what colour horses can differentiate and what they cannot determine. We have to bear in mind that our perception of colours is different from animals. We are trichromats’ (three colours) i.e.; we have different types of colour receptors. Hence we can differentiate between different spectrums mainly green, blue and red which combine together to form different colours.

A common butterfly has fifteen types of colour receptors whereas birds only have four types of colour spectrum. Many people believe that horses and dogs have the colourless world. But studies suggest that horses do, certainly, see colours. Before going further let’s get the basics terms clear.

You may be wondering what exactly receptors are?

Receptors respond to different colours (wavelength) of light which is found at the back of an eye. It helps the brain to process the information and react to colours differently. Some living beings have different receptors (cone cells) while others don’t even have one.

Generally, the eye is operated by two types of photoreceptors- rods and cones. Rods help in vision in the darkness whereas cones are sensitive to colours. Sounds is made up of frequencies similarly light is made up of different wavelengths. The cone works according to the wavelength of the light.

Light is directed towards retina after it passes through the pupil, which consists of rods and cones. The information is decoded using photoreceptor; the decoded information is then passed to the brain in the form of a message. Each photoreceptor responses differently to wavelengths and some receptors prefer single wavelength.

The equine eye is the largest of all mammals and hence Horses have the different perception with colours, distance, and vision. Some studies determine that horses can see red and others conclude that they can recognize blue not red. This is the result of the flaws in studies causing the horse to respond to brightness and darkness instead to the colour.

Researchers have observed that horses have two types of receptors; however, they are not sure about the colours horses brain support. Horses respond to colours according to their colour receptors and information processed by the brain. They, as a matter of fact, have a blue cone receptor and a second receptor that is most sensitive to light and is more or less flanked by that of the human red and green cone.

Being a prey animals horses have an advantage as their eyes are on both sides providing them wide and circular view, which helps them detect the stalking animals. Just like humans, horses do have a blind spot/area in front of its forehead. That is why they say, never approach a horse with horse clippers in hand as they might hear the buzz of the clipper and may not see you, which will panic them and controlling them in such times will get difficult. The horse’s possesses two visions monocular (one eye) and binocular (both eyes). When they are relaxed their monocular vision is working and while inspecting they will move their head or whole body to bring binocular vision in focus.

Earlier it was believed that horses have low poor vision and short-sighted but horses have a good binocular vision with high tendency of long sight. As compared to humans, horses lack colour vision and colour insight but their night vision is far better than ours.

• Colour acuity 

Horse vision is similar to the people who are colour-blind. So horses are able to see blue and the colour in between red and green. Bright colour usually appears brownish or greenish to your horse.

There are some colours which can spook the horse. Yellow and orange are the colours horses are not comfortable with. But this is not a common scenario as some horses react negatively too colour red too. It can depend on the different horses.

• Night vision

Horse’s eyes are sensitive to less light which allows them to see fairly well at dusk but they can’t adjust easily to darkness. Their eyes have light-sensitive cells which can spook them while entering the dark or bright building. Also, they have large pupil which allows them to see during night time.

Tapetum lucidum is a membrane at the back of an eye which reflects light, it also helps in their night vision. They are not dependent on the flashlights or light switch in the dark. They have a problem in the adjustment in light but night is better for them than daytime due to quick shifting in light levels. The sudden change also gives them less time to adjust.

This high sensitivity is due to more rods, the proportion of rods to cones is about 20:1. This also helps in better vision on cloudy days than sunny days. The large eyes of horse and night vision powers assist them in the detection of the predators. Horses are able to see more details than other animals.

Different experiments results vary from each other. This may be possible due to the distortion while experiments. But it cannot be stated clearly whether red is visible to the horse or green. There are different conclusions which are stated below.

Sometimes, horses distinguish between the colours using the brightness and not colours. Sometimes a red object may appear to be black or the mix objects may appear to them of the same colour.

Many experiments are conducted to check the ability of the horse. There are different observation done but with the only common result of the colour blue. It was also observed that horses can see the colour grey when experimented yellow with grey and green with grey. They can distinguish red from grey too at some level. Some experiments states that the horses are yellow-green colour deficient. So, horses see the world as any human except for green and yellow colour. Horses work fine with limited colours using different observations such as brightness, depth, and patterns to function properly.

Understanding how the horse sees help the owner while training. They are not able to see the details like humans due to lower colour perception. They use the pattern to track the path or the sound of the owner to reach them as they can easily navigate the trail, especially at night time.

Horses can see the colours but they react differently to different colours and have limited colour choices. Some colour spooks them while the others can calm them down. Their perception and reaction towards the entire colour combination solely depend on the horse and it varies from horse to horse.

Horse visions do not change much throughout their lifetime. They don’t have to read nor do needle-points work which don’t affect their eyesight much. But they can develop the cataract as the effect of aging which has little effect on them as they don’t require precision.

We can never actually understand the horse’s vision towards the world. We can just try to observe and understand using our own perception towards colours.