Why Do Animal Eyes Glow Green When Illuminated at Night? What Causes Red - Eye in Flash Pictures?
Why do animal eyes glow green when illuminated at night? What causes "red - eye" in flash pictures?
I’m sure everyone has experienced seeing a scary cat late night on an October night with it’s eyes glowing ever so brightly or taken a really good picture but once you get it developed notice that your masterpiece of a picture has “red-eyes” on every person in the picture. I’ve always wondered what the reason for animal’s eyes glowing under a fluorescent light was and never would have thought that it is completely due to reflection. Most animals have a reflective surface located behind their retinas. That reflective surface is better known as the tapetum lucidum, which enables the animal to see in the dark. What I thought was very strange is that humans don’t have the tapetum lucidum like animals do. Not all animals have this but many do including; cats, dogs, deer, horses, cattle, and ferrets. Often when you see the light reflecting off of an animals eyes you might think that the color that is being reflected is the same for all animals, but in reality they are actually different. For instance, the reflection of a cats eye under fluorescent light glows a bright green color whereas other animals can different shades of that whitish-green color. Even animals of the same species can have a different reflection color. The color change in an animal’s eyes is due to multiple different substances (riboflavin or zinc) in the tapetum of the animal. A lot like the animal’s eye, the human eye also reflects in light. If you’ve ever seen a picture of humans and all their eyes have the “red eye” you have witnessed human eye reflection. The reflection color of the human eye looks red due to the fact that there are a ton of blood vessels on the retina.
Works Cited
I’m sure everyone has experienced seeing a scary cat late night on an October night with it’s eyes glowing ever so brightly or taken a really good picture but once you get it developed notice that your masterpiece of a picture has “red-eyes” on every person in the picture. I’ve always wondered what the reason for animal’s eyes glowing under a fluorescent light was and never would have thought that it is completely due to reflection. Most animals have a reflective surface located behind their retinas. That reflective surface is better known as the tapetum lucidum, which enables the animal to see in the dark. What I thought was very strange is that humans don’t have the tapetum lucidum like animals do. Not all animals have this but many do including; cats, dogs, deer, horses, cattle, and ferrets. Often when you see the light reflecting off of an animals eyes you might think that the color that is being reflected is the same for all animals, but in reality they are actually different. For instance, the reflection of a cats eye under fluorescent light glows a bright green color whereas other animals can different shades of that whitish-green color. Even animals of the same species can have a different reflection color. The color change in an animal’s eyes is due to multiple different substances (riboflavin or zinc) in the tapetum of the animal. A lot like the animal’s eye, the human eye also reflects in light. If you’ve ever seen a picture of humans and all their eyes have the “red eye” you have witnessed human eye reflection. The reflection color of the human eye looks red due to the fact that there are a ton of blood vessels on the retina.
Works Cited
Cited: http://phanichakravarthi.blogspot.com/2011/07/why-do-animals-eyes-shine-in-dark.html