Unique Coats: The Science Behind Dog Coloration

Have you ever wondered why dogs have wildly different colors of fur? Our team at WonderWoof wanted to share this interesting topic with our fellow WonderPups! We looked to the fields of art and biology to help us understand the color of our favorite canines. From the Chocolatest of Labradors to the Greyest of Hounds, it turns out that dog coloration is determined by two particular pigments present in each breed’s genetics: Eumelanin and Phaeomelanin. Lets break down how these pigments work:

Does your dog have black fur? Eumelanin is a pigment in a dog’s genes that expresses itself in a dog’s coat color, nose color, and eye color. This will determine how “black” a dog’s coat is or if they have any black markings on their coat at all. Breeds such as a Black Lab or a Newfoundland dog, for example, will have a strong concentration of Eumelanin in their coats. Do you wonder why most dogs have black noses? This is because the Eumelanin pigment is the default coloration for most dogs! Eumelanin can be altered slightly so that it produces a pigment closer to gray, brown, or light brown. These hues respectively are called “blue,” “liver,” and “isabella.” If a dog’s Eumelanin goes more liver, for example, not only will their coat color be affected but also their nose color and eye color.

Does your pup’s fur stray more into the red-tones? A secondary pigment called Phaeomelanin is also an important determinant of a dog’s fur. Unlike the way that Eumelanin also affects the coloration of a dog’s nose and eyes, Phaeomelanin only affects their coat color. Also, Phaeomelanin only expresses one color — red — as opposed to two groups of color like Eumelanin’s liver and black. It includes dogs with truly red coats (such as an Irish Setter), and also includes a wider range of hues including golden tans, yellows, and oranges. A dog’s genetics determine how pronounced the Phaeomelanin is and how dense the hue of their coat is. Think your dog’s coat is totally unique? You’re absolutely correct: while families tend to have similar coat patterns, stray spots here and there will differ from dog to dog. This is how every coat color and combination end up being truly unique!

What if your dog’s coat is white? Good question: it really doesn’t fall under either of the pigments we’ve explained! White, the presence of all color in the visible light spectrum, is the absence of all color and information in a dog coat. Dogs have white coats whenever both of these pigments are inhibited or whenever the Eumelanin and the Phaeomelanin are extremely weak. For example, whenever a dog has a completely white body and a black nose and darker eyes, it means that the Phaeomelanin is dominant but unpronounced. However, in the case of albino dogs or breeds where the genetics don’t clearly delineate a dominant/recessive relationship, the eyes will be blue and the nose will likely be pink because the Eumelanin is not affecting those traits. A true albino dog would have red eyes, but it is more common to find dogs with weakened traits as opposed to the anomaly of actual albinism. “White spotting” (under the technical term epistasis), in a dog refers to white patches that lay on top of any Eumelanin or Phaeomelanin on a dog. This means that any dog coat color can be speckled with white regardless of their dominant pigmentation.

Like the primary colors on the color wheel, small bits of pigment help determine a wide variety of color. These fundamental principles help us better understand the reasons behind each pup’s uniquely colored coat.

Have a colorful day, WonderPups!