Why are cats called blue? - briefly
The term "blue" in reference to cats does not denote the color blue but rather a specific shade of gray. This designation originates from the historical British term for gray, where cats with blue-gray coats were simply called "blue cats."
Why are cats called blue? - in detail
The term "blue" in reference to cats is a bit misleading, as it does not pertain to the color blue as we commonly understand it. Instead, it refers to a specific gray coloration in a cat's fur. This gray hue is often described as "blue" due to the way light reflects off the tips of the fur, giving it a bluish tint. The gene responsible for this coloration is a dilution gene that lightens the black pigment eumelanin, resulting in a gray coat.
The dilution gene affects all black pigments in the cat's fur, eyes, and nose leather. In cats with blue fur, the black pigment is diluted to gray, the dark brown pigment is diluted to a light brown or fawn color, and the yellow pigment remains unchanged. This genetic modification is recessive, meaning that a cat must inherit the dilution gene from both parents to exhibit the blue coat color.
Blue cats can be found in various breeds, but some breeds are more commonly associated with this coloration. For example, the Russian Blue is a well-known breed that exhibits a striking blue-gray coat. Other breeds, such as the Korat and the Nebelung, also feature this beautiful gray hue. Additionally, the British Shorthair and the Chartreux breeds are famous for their blue coats, which are often accompanied by striking copper or gold eyes.
It is essential to note that the term "blue" can also refer to the eyes of certain cat breeds. For instance, the Siamese cat is renowned for its vivid blue almond-shaped eyes. This eye color is due to a specific genetic mutation that affects the production of melanin in the iris. The lack of melanin in the back of the iris allows light to pass through and be reflected back, giving the eyes their characteristic blue appearance.
In summary, the term "blue" in cats refers to a specific gray coloration in their fur, resulting from a dilution gene that lightens the black pigment. This genetic trait can be found in various breeds and is a result of recessive inheritance. Additionally, the term can also describe the striking blue eyes seen in certain breeds, which are due to a different genetic mutation affecting melanin production in the iris. Understanding these genetic mechanisms provides insight into the fascinating world of feline coat and eye colors.