Whether you are a hunter or just curious about what animal is in the woods near you, being able to identify them by their eyeshine is a pretty cool skill to have. I did a lot of research but had trouble finding a good resource. So, I decided to compile everything I learned and share it here with you. This is what I found out.
In identifying animal eyes at night, you should consider four primary factors – the color, the shape of the eyes, pupil slit orientation, and eyelid shape. Predatory animals have glowing eyes with vertically elongated pupils, while harmless animals have horizontally elongated pupils.
In total, there are five primary eye shine colors that are visible in animals: blue, green, white, yellow, and red.
Here is an eye shine chart of 38 animals:
By the way, this fascinating book on Amazon covers how animal eye color affects behavior.
This article will examine why some animals have eyes that glow in the dark and how this feature helps them survive. We’ll also share a helpful eyeshine chart that you can use to identify animal eyes in the dead of night.
Why Do Animal Eyes Shine at Night?
Before we look at what colors go with actual animals, let’s talk a bit about the science.
Many animals have a thin reflective membrane at the back of their eyes, known as tapetum lucidum. This reflective membrane layer lies behind the iris and acts as a retroreflector, which means it reflects light back at the source – in this case, back at your flashlight.
It reflects visible light passing through the retina back to increase the amount of light on the photoreceptors. The presence of a tapetum lucidum gives nocturnal carnivores superb night vision.
Animals reflect the light directly toward the light source to give the retina a succinct image to analyze. Cats have incredible night vision because the reflective effects boost their night vision.
By matching the original and reflected light, the reflective layer maintains the image’s contrast and sharpness. The reflective layer uses constructive interference to increase the amount of light passing through the animal’s retina.
This phenomenon is also known as eyeshine because the glowing eyes are simply reflections of the light source trained at the animal. Shining light directly on the face of an animal with a tapetum lucidum causes the eyes to glow.
Eyeshine comes in various colors, including white, yellow, red, blue, pink, or green. Since the reflective layer is iridescent, the pupils’ color is affected by the angle of vision, eye color, and the mineral makeup of the tapetum lucidum.
Related Which Animals’ Eyes Reflect at Night? | A Biological Insight.
Night Vision and Eyeshine
A tapetum lucidum improves an animal’s ability to see in the dark and low-light conditions. The reflective eye membrane is typical in mammals, reptiles, invertebrates, and amphibians.
The eyeshine color depends on the animal and can be red, orange, yellow, pink, blue, or green. The sheen depends on eye color, the shape of the eyes, and the light’s angle shining on the animal.
The intensity of the eye glow varies between species, with some animals glowing brighter than the rest. The animals with the brightest eyeshine have excellent night vision because their eyes have fewer cones. Unfortunately, perfect night vision comes with limited color vision or complete color blindness.
Eyeshine in Predators
Most of the nocturnal predators have a tapetum lucidum to help them see in the dark. Dogs, house cats, big cats, alligators, and ferrets are some of the predators with eyes that reflect in the darkness.
Improved night vision is essential to these predators because it allows them to track prey in pitch darkness.
Cool Fact: Some predatory fish, like walleye, need excellent night vision to hunt in the dark, deep waters. As a result, they have reflective eyes.
Interestingly, while owls have eyes that glow in the dark, they lack a tapetum lucidum in their eyes.
Glowing Eyes in Predators
Unsurprisingly, some of the prey targeted by the predators with improved night vision developed a tapetum lucidum layer. The layer evolved as a defense mechanism to help these herbivores detect predators in low-light conditions.
Some non-predators with excellent night vision include cattle, deer, pigs, camels, kangaroos, and horses.
Identifying Animals by Eye Glow at Night
While it’s possible to identify some animals by their eyeshine, the eye glow color is more of a guideline than accurate science.
Several factors influence the color of an animal’s eyeshine, including:
- The color of the light source – flashlight, camera, LED, or moonlight
- The color of the animal’s eyes
- The size of the animal’s retina
- The distance between you and the animal
- Your position and light source angle
Here are charts grouping animals by their eyeshine color:
Eyeshine Charts
It’s important to note that accurately identifying an animal at night might require more information than just its eye color. If you can, try to use the animal’s general size, behavior when looking at you, habitat, eye size, and more.
Related What Does Moon Overhead and Underfoot Mean?
Animals With Red Glowing Eyes at Night
Some animals with characteristic red eyes at night include:
- Alligators and crocodiles- The large eyeballs of alligators and crocodiles glow fiery red in the dark, making them easy to identify. If you’re near a river, lake, or swamp in an area that these creatures live in, take extra caution if you see red eyes in the dark.
- Owls- Owls are nocturnal birds with big eyes that glow red or orange after dark.
- Red fox- Foxes have red glowing eyes with perpendicular pupils.
- Rabbits- A rabbit’s eyes will exhibit a light red tone when you shine a light on them.
Animals With Yellow Eye Glow at Night
Some animals have glowing yellow eyes at night, including:
- Bears- A bear has dark brown eyes that take on a bright yellowish glow when you shine a light on them in the dark.
- Cats- Some cats have eyes that give off a yellow glow in the dark, but this can vary depending on the cat in question.
- Deer- A deer’s eyes glow yellow in the dark. As deer often live in the same habitats as bears, you should also look at the height and size of the eyes to determine which animal you’re looking at.
- Raccoons- Raccoons have big eyes that glow bright yellow in the dark.
- Chinchilla- Commonly kept as exotic pets, chinchillas also have big eyes that glow yellow in the dark.
- Panthers- This big cat has smallish eyes that glow yellow in the dark. You might not see the yellow glow if you shine the light directly on their face.
Animals With Glowing Green Eyes at Night
Some animals with eyes that glow green in the dark include:
- Dogs- Some dogs can have an eerie green nighttime glow that can be unsettling in the dark. A dog’s eyeshine can take on different colors, including blue, orange, green, and red.
- Foxes- Some foxes have an intense green glow in their eyes as they forage for food after dark, though a few types of foxes have white or yellow eyes instead.
- Opossum- Opossums have big eyes that light up green in the dark. You’re likely to find them perched up high on a tree at night.
Animals With White Eye Glow at Night
Some of the animals with eyes that glow white in the dark include:
- Coyotes- Coyotes have big eyes that glow bright white in the dark. While they’re predators that typically hunt in packs, you don’t need to panic if you see a pack of white eyes staring at you, as coyote attacks on humans are extremely rare.
- Deer- A deer’s eyes will reflect the white light of a camera equipped with a flash to assume a bright white glow in the dark.
- Tigers- Tigers would be difficult to spot in the dark were it not for their large eyes that glow white in the dark.
Why Human Eyes Don’t Shine
Human eyes do not have a reflective layer called the tapetum lucidum. In fact, all haplorhine primates are diurnal and do not have the tapetum lucidum.
To read more about this topic, go here.
Conclusion
Shining a flashlight into the darkness only to see a pair of glowing eyes staring back at you can be a bit frightening. And unless you know whether those eyes belong to a dangerous predator or a harmless herbivore, you won’t know whether to ignore them or be on your guard. Fortunately, you can identify an animal by its eyes at night if you have the correct information.
Some animals have eyes that glow in the dark because they have a special reflective membrane behind their retinas. The membrane is a unique adaptation to help their ability to see at night.
Most common eyeshine colors include white, green, red, yellow, and orange. The eye glow color depends on the specific animal, eye color, and light source, among other factors.
You’d need more information about an animal in addition to its eyeshine, such as habitat, size, behavior, eye size, and more, to identify it accurately.
Still, the included eyeshine chart should help. And don’t forget to check out this book on Amazon, it’s extremely helpful.
I hope this article has provided the info you needed. Thanks for reading!
For more, check out What Can Deer Smell? (How To Avoid Detection).
