The fascinating variety of cat eye colors results from some fascinating genetic interactions, development, and adaptation due to evolution. To fully understand how cats develop their distinctive eye colors, it’s essential to explore the structure of the feline eye and the role of melanin—the pigment that is also responsible for the color of your cat’s fur.
What Is The Science Behind Cat Eye Color?
In the iris of your cat’s eye, specialized cells called melanocytes produce melanin. The amount and type of melanin, combined with the way light scatters through the layered structure of the iris, creates the various colors we see. Most kittens are born with blue eyes, which gradually change and reach their permanent color by about 6-8 weeks.
There are two forms of melanin in your cat’s eyes: eumelanin (which produces brown and black pigments) and pheomelanin (which creates red and yellow hues). The ratios and interplay of these pigments within the structure of the iris create a wide spectrum of cat eye colors.
High levels of melanin result in darker cat eye colors, while low levels produce lighter colors like green and blue.
What Color Eyes Do Cats Usually Have?
Copper and Orange Eyes
Warm-toned eyes of orange and copper result from high concentrations of pheomelanin – the melanin responsible for red and yellow hues – in the iris. Tones can vary from light amber to deep copper and are frequently seen in British Shorthairs, Persian, Burmese, and Abyssinian cats.
Green Eyes
Green is the most mystical and enigmatic of all cat eye colors. It occurs when a moderate amount of melanin combines with the Tyndall effect, which explains how light enters the eye and which wavelengths are reflected out. Cat breeds that commonly have green eyes include Russian Blues, Norwegian Forest, and Egyptian Mau cats.
Blue Eyes
Blue eyes in cats are different from other cat eye colors in one important respect: they result from a lack of melanin. The light that enters the iris is scattered, and the shorter wavelengths of blue light are scattered most. This phenomenon is the same reason that the sky appears blue. Blue eyes are often linked to albinism or the presence of the white spotting gene. Cats famous for their striking blue eyes include Siamese, Himalayans, Ragdolls, and Balinese.
Heterochromia
A striking feature of cat eye colors is when they have two different colored eyes. This condition, known as heterochromia, is more common in white cats and specific breeds like Turkish Vans. Differences in melanin distribution during early development are responsible for this fairly rare condition.
Is Cat Eye Color Linked To Health Concerns?
Cat eye colors can sometimes indicate a genetic predisposition or an underlying health condition. For example, cats born with white fur may be more likely to have congenital deafness. The genes responsible for white fur and blue eyes can also affect the development of the inner ear.
There is also a strong relationship between coat color and cat eye color. Pointed cats (like Siamese) almost always have blue eyes due to a temperature-sensitive enzyme that affects both fur and eye pigmentation. Similarly, solid black cats typically have orange or copper eyes linked to genetic factors that affect melanin production.
If feline genetics interests you, check out this article on fascinating genetic anomalies in cats.
Does Cat Eye Color Change?
Cat eye color is usually determined by about 8 weeks of age, but there are some instances where subtle changes in eye color may occur throughout their life. Things like illness, injury, or even medications can impact eye color. If you notice a sudden change in your cat’s eye color, it may indicate an underlying health concern, which is best investigated by a veterinarian as soon as possible. Check out our article on warning signs of disease in cats. Common conditions that result in a change in eye color include:
- Jaundice: yellowing of the whites of the eyes can indicate liver problems
- Glaucoma: an increase in the pressure of the eye that can lead to changes in eye color and vision loss
- Uveitis: an inflammation of the eye that can cause discoloration or cloudiness
Do Cat Eye Colors Have Historical and Cultural Significance?
It’s not hard to see why cat eye colors have historically held significant cultural importance. In ancient Egypt, cats with gold-colored eyes were believed to embody the sun god Ra. Medieval Europeans believed that cats with heterochromia had mystical properties.
What Are Some Fun Cat Eye Facts?
Cat’s eyes are truly fascinating. Photo by Eduardo Goody on Unsplash
- Cats have vertical pupils, which are an evolutionary adaptation for hunting. This unique pupil shape allows the cat more precise control over how much light enters the eye.
- If you’ve ever seen a cat’s eyes in the dark, you may have noticed that they’re almost reflective. The cause of this glow is a reflective layer called the tapetum lucidum, which enhances the cat’s ability to see in low-light conditions. The reflective studs used to illuminate the lanes of a road at night are called cat eyes because of this reflective quality.
- Cats have a third eyelid that produces tears and keeps the eye moist and protected.
Final Thoughts
The impressive variety of eye colors in cats reflects their rich genetic diversity and evolutionary history. While eye color is usually linked to breed and genetics, monitoring your cat’s eyes for sudden changes that might signal a health issue is crucial. Ultimately, whether your feline friend looks at you adoringly through emerald eyes or sparkling blues, they’ll melt your heart regardless of their eye color.
