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Russian Blues are beautiful, mysterious cats with an instantly recognizable shade to their coats (hence their name). However, the eyes of the cat are even more captivating, as they are always a vibrant emerald green.
According to the TICA (The International Cat Association) and CFA (Cat Fanciers’ Association) breed standards, the only eye color that can be registered as true to the breed is a vivid green. But confusingly, very young Russian Blues don’t have green eyes, even though they are 100% purebred. This is because all kittens, regardless of the breed, are born with blue eyes, and in Russian Blues, the blue color changes to yellow before transitioning to their final emerald shade. For this reason, TICA adds a section referencing this change in their breed standard.
How Common Are Russian Blue Cats?
Russian Blue cats have gained popularity in recent years, with the breed rising from relative obscurity to a common household pet in the US and the UK since the 1900s.
They originated in Russia, in the port of Arkhangelsk on the White Sea, about 150 miles south of the Arctic Circle. That’s the reason why they’re sometimes called the Archangel cats. While many cats have a blue coat, special conditions must be met to classify a cat as a true Russian Blue, one of which is their blue coat with silver tips and bright green eyes.
At What Age Do a Russian Blue Cat’s Eyes Turn Green?
According to TICA, at around 4 months of age, a Russian Blue kitten’s eyes will begin to turn from yellow to green. This process starts with a green ring forming around the pupil and slowly growing until the entire iris is bright green. This change coincides with puberty and maturity.
Why Do a Russian Blue’s Eyes Change Color?
A cat’s eye color is determined by the amount of melanin in the iris, the colored part of the eye. All kittens are born with blue eyes because their melanocytes (the cells responsible for producing melanin) are not yet mature at birth. When kittens open their eyes at around 7–10 days old, their eyes appear blue due to light refracting off the unpigmented iris. As the kitten grows, the melanocytes begin to mature. Around 7 weeks of age, these cells start producing melanin, and by approximately 4 months, they are fully active. This gradual increase in melanin is what causes the slow change in eye appearance from blue to the cat’s adult color.
In the case of Russian Blue cats, their eye color typically changes from blue to yellow, and by 4 months of age, the green color starts to appear around the pupil. Green eyes contain a small amount of melanin, whereas brown or copper-colored eyes have the highest levels of melanin.
What Is the Rarest Eye Color in Cats?
Cats can have various eye colors, including:
- Blue
- Green
- Yellow
- Orange
- Copper
- Brown
However, the rarest eye color combination found in cats is heterochromia, commonly referred to as “odd eyes.” Complete heterochromia (heterochromia iridum) occurs when a cat has two different-colored eyes, such as one blue eye and one green or amber eye. The second type is segmental heterochromia (heterochromia iridis), which happens when two different colors appear in the same eye—typically with one color surrounding the pupil and another around the outer edge of the iris.
Both forms of heterochromia are most commonly seen in white cats.
Are Green Eyes Rare in Cats?
Green eyes in cats are common but not the most common color. Yellow-eyed cats take the top spot for the most common eye color, but that doesn’t make them any less beautiful.
There are several types of green eyes on cats; some are a brilliant emerald, and others are a murky, almost hazel color (and all shades of green in between).
Both pure breeds and cross breeds have green eyes, and the green-eyed cats that are part of the breed standard include:
- Russian Blue
- Nebelung
- Korat
How Can You Tell if a Kitten Will Have Green Eyes?
If a kitten’s eyes are a lighter color or less pigmented when they’re very young, it may indicate that they will have green eyes when they mature. However, this doesn’t change the fact that all kittens are born with blue eyes, and it’s not possible to accurately tell which color their eyes will be until they begin to reach maturity.
Final Thoughts
Russian Blue cats are remarkable creatures that have become a common sight in cat lovers’ homes in recent years. Their vivid green eyes have a part to play in their popularity, with all purebred Russian Blue cats having green eyes. The only exception is if the cat is not yet fully mature; a Russian Blue kitten’s eyes will be blue when they first open and will slowly mature to yellow, then to green.
Featured Image Credit: Popova Lena, Shutterstock
