Is a pair of glowy eyes a bad omen?We all have heard scary stories as kids and the glowy eyes of cats are still some of the most haunting ones. The explanation behind it is simple.They are very active at night while we humans are sound asleep. The glow just helps them see at night and it gives them night vision. Tapetum lucidum is a layer in a cat’s eyes and this word is derived from the Latin words ’tapetum’, meaning ’tapestry’ and ’lucidum’, meaning ‘bright’, ‘shining’, and ‘clear’. It is a term for ‘shining layer’. If a cat’s eye is glowing during the daytime, it means the pupils are detecting unwanted light which causes a disturbance in their vision. Continue reading to know more about this membrane and its role in glowy cat eyes. Did you know not only cats but dogs, raccoons, and a lot of other nocturnal animals have glowy eyes?If you are interested in knowing more about cats do check out our other articles on why do cats like to be pets and why do cats chase their tails.Are cat’s eyes actually glowing?If you clearly think about it, anybody who has come across a cat at night would agree that they have seen their eyes glow. However from a science standpoint, they are not actually glowing. Cat eyes are quite different from the structure of human eyes.While all eyes are able to reflect light to some extent, some animals have a unique reflective surface called a tapetum lucidum which is a layer at the back of the retina that provides the illusion of glowing at night and allows the cat to see clearly in the dark. In humans, the reflective surface, tapetum lucidum is absent. This is why when you snap a photograph at night with a flash on your camera, there is a red eye effect rather than glowing eyes. When a light source hits a cat’s eyes in a dark place, it either hits the retina or passes through or around the retina and comes in contact with the tapetum which is behind the eyeball. The former, common in all eyes, is a photo sensitive sheath. A bunch of specialized cells called photoreceptors in this sheath convert the light into signals which are recognized by the brain to form an image. The latter is a guanine containing tissue layer. This guanine is the mastermind behind the mesmerizing, glowing eyes that glow in the darkness. It works as a reflective surface, similar to a tiny mirror, and bounces back light in the same direction as it came from. This light travels back to the retina, providing it with a second chance to transform the light rays which were previously missed into electric impulses. As a result of the reflection, the pupil appears to glow. These impulses travel through the optic nerve of the brain enabling it to create an image. This might be a somewhat fuzzy image that is not as clear as the one generated initially by the light from the retina. However, it is more than sufficient for a cat as long as it can acquire a sense of what it is looking at.While this might not be very important to humans as we spend the nights sleeping, for cats and many other nocturnal animals this vision in the dark is an essential surviving feature that allows them to detect prey and predators.Why do cats eyes glow different colors?The glow of a cat’s eyes can be of various colors, like bright red, green, and yellow. Regardless of the color, they always send a shiver down your spine when you spot them in a pitch dark place. For a very long time, this eye shine was considered something supernatural. But the explanation is quite simple.Cats, just like humans, are different from one another. Apart from major differences in specific features like the color and breed, there are minor differences even between the same species. One such minor feature is the cause of distinct colors of glowing eyes. The tapetum lucidum is a layer made of cells surrounded by blood vessels that contain zinc or riboflavin designed specially to reflect light. The levels of zinc or riboflavin determine the glow color. They only glow in dark places while reflecting lights. The most common color observed in cats is green. The Siamese cat has blue eyes but these glow red while other cats with golden and green eyes have a green shine in the dark. The riboflavin present in the tapetum lucidum reflecting sheath is yellow as it takes in blue light and also reflects yellow light. The shine also varies based on which angle the light falls as this causes a difference in reflection.Does it happen to all cat breeds?All cat breeds have glowy eyes except for some members of the Siamese cat and some cats with blue eyes which might lack tapetum. This is also observed in some dogs. There is no huge explanation as to why this is caused, however scientists state that this is an abnormality known as retinofugal abnormal pathways.It is similar to a deficiency or abnormality in humans. These cats have a red glow just like in humans since the light is not reflected by the tapetum lucidum. Instead, it hits the blood vessels and gives a red eye effect. On the other hand, your cat might have tapetum lucidum, but not glowy eyes at times. This is because of the insufficient light which the eyes might not be able to reflect. This means they might not glow. The colors can vary from breed to breed or cat to cat. Since cats hunt at night, almost all of them have tapetum lucidum, a sheath of cells surrounded by blood vessels that contain zinc or riboflavin. If a cat’s eyes do not glow in the dark, despite having a light source and tapetum, it means that the cat might be having a hard time seeing as the light is not reaching the retina or tapetum lucidum properly.Do both their eyes glow or only one?Mostly both of the cat’s eyes glow. In some minor cases, it might be different. For example, in an odd eyed cat, the eye shine in one eye might differ from that of the other. In a cat with one blue eye, this eye might lack reflective cells and produce a red eye effect. While the other eye with different colors will properly function due to the presence of light-reflecting cells.The Merek veterinary manual says that cat pupils turn into a slit when there is a bright flash of light.Here at Kidadl, we have carefully created lots of interesting family friendly facts for everyone to enjoy! If you liked our suggestions for why do cats eyes glow then why not take a look at why do cats suck on blankets, or caracal facts pages.
Is a pair of glowy eyes a bad omen?
