Why Are Black Cats Black?

The Primary Gene for Producing Coat Color

The gene responsible for coat color in cats is known as the melanocortin 1 receptor (MC1R) gene. This gene controls the production of the pigment melanin, which gives color to a cat’s fur, eyes, and skin. 

The MC1R gene has several different variations, or alleles, that can affect the color of a cat’s fur. The allele for black fur is known as the non-agouti allele, which causes the cat to produce only eumelanin. 

Cats have two coat color pigments: eumelanin, which is black or brown, and pheomelanin, which is red or yellow.

The Science behind black cats' coat color

The gene responsible for producing eumelanin is known as the ‘B’ gene within the cat community. There are three variations of the B gene: B, b, and bl.

Every cat has two copies of this gene, one from its mother and one from its father. The B form is dominant over the b and bl forms. If a cat carries the B gene, it produces a large amount of eumelanin, resulting in a black coat. 

The b allele is recessive to B and produces less pigment, leading to a brown coat, sometimes called “chocolate.” The b1 allele is recessive to both B and b, and it leads to a light brown or “cinnamon” coat.

Cats possess additional genes that influence their coat color, such as the agouti gene, which regulates the distribution of eumelanin and phaeomelanin in the hair shaft. 

The interplay of these genes can produce different shades of black, such as charcoal or blue-black. Many cat breeds can have black fur, and Bombay cats are well-known for their consistent black coloration. 

You can learn more about the Bombay cats here: