Expert explains how Dogs see the World and why Eyes glow in the Dark
Similar as humans who have red-green colour blindness, dogs struggle to differentiate between various shades of yellow, green and blue.
Most owners have noticed their dog’s eyes glowing under touch light – but not many know why this happens or have even thought to question it – but the Kennel Club has provided an explanation
It’s a common misconception that dogs can only see in black and white, but scientists have proven this to be a myth as dogs can actually see a wide array of colours.
Similar as humans who have red-green colour blindness, dogs struggle to differentiate between various shades of yellow, green and blue.
A Blue Cross statement reads: “Humans have three cones (photoreceptor cells) in their eyes; blue, red and green whereas dogs have two; blue and another that falls between the human red and green cone.
“However, these colours do not affect a dog’s sight. In fact, dogs have more rods in their eyes than humans, which allow for better vision in very low light.”
In both humans and dogs, the eyes and brain work together to translate light into colour.
Although colour doesn’t actually exist, the brain turns these light wavelengths into various shades making us believe we’re seeing reds, yellows, blues and so on.
“Different animals can see different kinds of colour from a broad range of spectrums. Some see very little colour, while creatures such as bees and butterflies see more than us as humans,” the Blue Cross statement adds.
“Human eyes also have more than 120 million rod cells that process low level light and the shape of objects, but not colour. This all makes it incredibly difficult to test whether our animals see in the same colours that we do.”
It is thought dogs can see better in the dark than humans thanks to a part of their eye called the tapetum lucidum.
This special layer reflective cells behind the retina acts as a mirror within the eye, reflecting the light that enters it, and giving the retina another a second opportunity to register that light.
A statement from Kennel Club America reads: “You’ve no doubt seen that eerie, greenish-yellow glowing look of a dog’s eyes when light hits them at night from headlights or a flashlight, and in photos (caused by the camera flash). What you’re seeing comes from the tapetum.
“The colour of the tapetum as it reflects light back and forth can vary from a green, blue, orange, or yellow hue. This coloration often changes over the first three months of life, according to the American College of Veterinary Ophthalmologists .
“Some dogs, most commonly those with blue eyes, don’t have a tapetum. So, when you take a picture of these dogs, rather than getting the greenish-coloured reflection from the tapetum, you instead often get red eyes – coming from the red blood vessels in the back of the dog’s eyes.”
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Source: Spy News Agency
