Why do kittens have blue eyes that change colour later?

When faced with a very young, fluffy little kitten it can be hard to decide what is the most adorable thing about them, but one thing that most young kittens have in common are their large, bright and inquisitive clear blue eyes! However, much as many babies that are born with blue eyes often develop a different colour as they get older, so too do kittens’ eyes often change colour as they get a little older, and a blue-eyed kitten may well grow up to be a green, amber or other colour-eyed cat!

If you have ever wondered how or why this happens-kittens born with blue eyes do not keep the blue colour as they get older-in this article, we will attempt to explain this in more detail, and attempt to answer the question of why kittens have blue eyes when young that then turn into another shade later on. Read on to learn more.

Young kittens

Kittens are born with their eyes closed, and they only begin to open at around ten to fourteen days of age, and the kittens’ mother helps with this process by licking and grooming her young, helping their eyes to unseal and open up for the first time. When this happens, the chances are that your first glimpse of the kittens’ eyes is likely to be blue-but the blue eyes of the kitten are not an actual eye colour per se, in that the blue shade is not caused by pigment, but by an absence of pigment.

It is only as they start to get a little bit older than the true pigment that is responsible for the resulting end eye colour becomes established, so unless your cat is a pedigree that has a predictable eye colour, you are unlikely to know what this colour will be until it begins to develop!

Cats and eye colour

As your kitten grows and develops beyond their first couple of weeks, they are developing and growing very quickly, both mentally and physically, and their bodies and appearances begin to take on the permanent traits that they will display for the rest of their lives.

Eye colour is not the only element that this may involve-Siamese kittens are born all white, and only begin to develop their colour points once they are a couple of weeks old!

Cats can display a reasonably wide range of eventual eye colours, including amber, brown, yellow, green and of course, blue too-and aside from the blue colour, the end colour is caused by the pigmentation present in the eye. Cats often have flecks of different colours within their eyes too, or in some cases, can display an eye that contains two different and distinct colours, such as blue and brown.

It is also possible for the cats’ two eyes to be different colours-such as one blue and one amber. This is more likely to occur in certain types of cats than others, particularly in this case, white cats, because the pigmentation present in the coat is related to the pigmentation present in other areas of the body too, like the coat.

DNA and pigmentation

As mentioned, eye colour for all shades other than blue is caused by pigmentation, while blue eyes are actually caused by an absence of pigment. The blue-eyed trait can also be identified in the DNA of the cat, and because few traits relating to DNA are standalone traits and unconnected to other factors, blue eyes can also indicate an elevated chance of certain other traits too-such as white fur, and potentially, congenital deafness.

In cats with one blue eye and one pigmented eye that has white fur, they are actually more likely to be deaf in the ear on the same side as the blue eye than they are in the other ear!

Permanently blue eyes

While most kittens lose their blue eye colour as they get older and develop pigment in their eyes, some cats retain their blue eyes for life, and while this is the most unusual cat eye colour, it is not hugely uncommon. Blue eyes are a breed trait in some breeds, such as the Siamese, as mentioned above, and also more common in white cats of indeterminate breed too.

This means that it is sometimes possible to predict or know with certainty if your cat will retain blue eyes when they grow up, if you have your heart set on owning a blue-eyed cat. However, if you are buying or adopting a moggy or mixed-breed cat, the chances are that their eyes will not be blue, although it is not unheard of!

If your adult cat does have blue eyes, it is possible that they have some heritage in their bloodline of a breed that retains adult blue eyes, and this can help to tell you a little bit more about your cat and their origins!