Why Do Cats Have Black Lips? How This Trait Evolved

Cats are fascinating animals, not only because of their silly antics but also because of how close they are to their wild counterparts. Domestication has only influenced 13 genes in our pets. Selective breeding has had a greater impact, yielding the 73 breeds accepted by The International Cat Association (TICA). They come in a broad spectrum of colors, patterns, and sizes, from the relatively enormous Maine Coon to the regal Persian.

Among the apparent differences are the variations in the color of the animals’ noses, ears, and lips. Have you ever noticed that your cat has pure black lips and wondered why? Again, selective breeding is at work, with official standards for each one. However, cats with black lips can trace their origin back 130,000 years to a wild common ancestor with the African Wild Cat (Felis silvestris lybica). Therein lies the fascinating answer to this question.

What Is Melanism in Animals?

Melanism describes the condition of a high concentration of the pigment melanin that accounts for the dark coloration of scales, fur, and hair in the animal kingdom. It also applies to a cat’s lips. Melanism isn’t always an all-or-nothing thing. Think about the color variations you see in many species, such as coyotes, chinchillas, and cats. Scientists refer to this trait as polymorphism for melanism or multiple variations, also referred to as melanistic variants.

Melanism in Felines

Cats are obligate carnivores and must hunt for food to survive. Many felines stalk their prey and rely on stealth. Most are either active during dusk and dawn or crepuscular, or come out at night and are nocturnal. Camouflage comes in handy for these lifestyles. It also explains the range of melanism, from the spotted leopard to the tabby coloration of the African Wildcat.

You may have noticed that the various tabby patterns and markings often resemble the exotic coats of their wild relatives, from the distinctive stripes of the tiger, to the unique and ‘unchangeable’ spots of a leopard. These similarities are more than just skin deep – they have a shared genetic code. Along with the myriad genetic variations that produce the vast array of coat colors and patterns is the agouti gene, which determines how and where pigment is displayed along the hair shaft and skin, including the lips.¹ The agouti gene is a dominant trait, which is why solid colored cats are not particularly common. As you can imagine, a patterned coat is much more beneficial when trying to hide in forests and grasslands, which is why it is the default or ‘wild type’ trait. In order to get a cat that is a solid color, two copies of the recessive ‘non-agouti’ genes are needed, so both parents need to either be carrying the gene or have solid coats themselves.

Despite selective breeding, the dominant agouti gene is still highly prevalent in the domestic cat population, and explains why even cats that do not appear to have a significant amount of black in their fur can still have dark pigmentation of the lips.

Abnormal Pigmentation

Some cats that have light-colored lips and mucous membranes may develop black spots on these areas, typically occurring in cats under 1 year old. Veterinarians usually see it in orange male felines, referring to this condition as lentigo. This coloration is also similar to that of the African Wildcat, supporting a genetic link to its development. The spots are not cancerous nor a cause for concern.

Final Thoughts

The genes that determine feline coat colors and patterns are quite complex, and selective breeding has resulted in even more variations and mutations becoming prevalent in the domestic cat population. However, as far removed as your lap-loving pet may seem from their wild ancestors, there are still many genetic traits they have in common. Many of the bold and beautiful cat colors we see today are simply the result of how and where the dark pigment, melanin, is distributed across their coat and skin, and even in cats that do not have significant levels of dark pigmentation across their body, may still have black lips, just like lions and tigers.

• See Also: My Cat Purses Their Lips When They Poop, What's Going On? Vet-Approved Reasons & FAQ

Featured Image Credit: Kaan Yetkin Toprak, Shutterstock