Blue is one of the rarest among dog coat colors. A blue coat can be solid in color or seem blue by its pattern, as in merle blue coats. In again other breeds the blue color only becomes visible when the dog is fully grown.
The blue color mutation is not something that appeared recently. An article written for the Ladies Kennel Journal dating back to 1897 already mentions two blue colored Pomeranians.
Recent studies have shown that coat color dilution in several dog breeds is caused by a dilution of the one or more mutations within or near the melanophilin gene (MLPH). The blue caused by this gene could be termed "born blue" since it is present from birth (as opposed to progressive graying seen in Kerry Blue Terriers, see further).
A blue Italian Greyhound
Photo: Mark Hatfield
Types of blue coats
There are four types of blue coats, depending on the pattern and whether or not the dog is born blue. They are all inherited differently.
Blue (dilute): a genetically black or dark brown coat becomes metallic blue-gray in appearance (blue Great Dane, blue Weimaraner). Always with a grey nose or paw pads.
Blue (progressive silvering): puppies are born black, but become blue-gray in adulthood (Kerry blue terrier). Other breeds in which progressive blue can be found: Puli, Havanese, Briard, Poodle and other breeds. Always with a black nose. See Kerry blue terrier >>
Adult and puppy Kerry Blue Terrier
Blue-tick: black roaning on white. The blue coloring results from a black/white mottling which gives the impression of a navy blue color. Always with a black nose, e.g. Petit Blue de Gascogne, Blue Belton English Setter.
See bluetick dogs >>
Blue Merle: is a color pattern, more than a color, which looks like marbled gray on black as in the Catahoula leopard dog and the Australian Shepherd dog. Always with a black nose, sometimes blue eyes.
For more information, see: blue merle dogs.
Blue border collie
Photo: Robert Churchill
The type of blue we will be examining into further details here, namely "born blue", appears as a mutation of the base color black. Only when the base color is black the dilute will be blue, while a chocolate or reddish brown dilute will give a lilac, mousey silver.
A blue Pit Bull Terrier
Photo: Chris Johnson
Weimeraners have a coat color that is based on dilution. The breed is predominantly fawn/lilac, i.e. a chocolate dilute. However, Weimaraners can also be black dilute, resulting in a blue coat. The nose color is usually also affected by the dilution, resulting in a grey or black nose, instead of brown. The same goes for other breeds, such as the German shepherd dog, i.e. red carriers will have a more lilac shade and those dogs that are homozygous for black will have a pure steel blue color.
Blue dilution from black (eumelanin dilution) occurs Dobermans, Great Danes, Pomeranians, Chow Chows, Shar Peis, German Shepherds and even Newfoundlands. Shar Peis also have a chocolate dilute, called lilac. Chocolate dilutes are known under different names according to the breed: lilac, pearl, isabella, light fawn, cream, etc. In Shar peis lilac and isabella are sometimes registered as blues because most registers do not distinguish between the different varieties of blue.
(Dog breeds with a solid blue coat or blue-merle coat)
a blue dobermann (left), black doberman (center)
and a brown doberman (right)
Photos: Doug Miller (left), Nataliya Kuznetsova (center), Emmanuelle Bonzami (right)
In some breeds the blue variety is an accepted color, but this is not always the case. The standard may also vary according to the registry (FCI, AKC, CKC, etc.). Blue Weimaraners, for example, are disqualified in AKC. In Dobermans, the situation is reversed: Blues and Fawns are allowed in AKC, but not allowed in the FCI.
In few breeds, blue is not a standard coat color variety, but nevertheless a color purposely bred for by some breeders, as is the case for example in the Pug and Labrador Retriever (see further). Future will tell if these colors will eventually be accepted as recognized colors in these breeds. Opponents believe only colors accepted by the standard should be bred as the standard is a blueprint for the breed that preserves against variations that could ultimately be detrimental to the breed. Reversely, one could say that evolution and changes form an integral part of a breed's history and made them what they are today. Breed standards have been adapted accordingly on many instances. Without judicious outcrosses many of our favorite breeds would probably not be what they are today. However, the pros and cons of these debates would lead us far beyond the scope of this article.
In the Australian Shepherd, Catahoula leopard dog and Beauceron the coat appears blue by its particular pattern and is referred to as blue merle. For further information on Merle blue dogs, see: Merle dogs.
Dog breeds that have blue as a recognized color variety
Australian Cattle Dog
Glen of Imaal Terrier
Old English Sheepdog
Blue dog breeds (which have blue as only color variety, either blue-tick or progressive)
Kerry Blue Terrier
Grand Blue de Gascogne
Petit Blue de Gascogne
Petit Griffon de Gascogne
Basset Blue de Gascogne
Dog breeds for which blue is not (yet) a recognized color variety
A blue pug and white pug together with two standard fawn and black pugs
bred by FunnyFarmPugs
The dog's coat color is determined by a substance called melanin. There are two distinct types of melanin in the dog, eumelanin and phaeomelanin. Eumelanin will, in the absence of other modifying genes, give the color black or dark brown. Phaeomelanin is, in its unmodified form, red/yellow. In some dogs the coat color dilution can be accompanied by hair loss and recurrent skin inflammation, the so called color dilution alopecia (CDA) or black hair follicular dysplasia (BHFD).
Dogs with coat color dilution show a characteristic pigmentation phenotype. The coat colors are lighter in shade, diluted black (eumelanin dilution) giving a silvery grey (blue) and red/yellow giving a cream color (Isabella fawn, also referred to as lilac in some breeds). Note that dark phaeomelanin can ressemble lighter forms of eumelanin and both dark phaeomelanin and brown eumelanin are likely to be considered 'red' by many breeders, which only adds to the confusion.
In some breeds blue dilute is termed grey or silver, which further adds to the confusion. This is the case, for example, in the Tervueren, where a dog with diluted red hairs appearing as blue, is usually called grey.
In some dog breeds the blue color variety is associated with a specific coat texture. That is the case for example in the Thai ridgeback, where the blue color is almost always associated with a velvet coat texture, while the other colored Thai ridgebacks are can have either a short, a velvet or a long coat.
Blue dilution can sometimes be associated with health issues. An affection called CDA (Color Dilution Alopecia), formerly known as Blue Balding Syndrome or Blue Doberman Syndrome, causes the melanin in the hairshaft to clump together making the hair weak and breakable. Despite its former name this affection is not limited to Dobermans, but can occur in many breeds, most notable are blue Chow Chows, Dachshunds, Whippets, Standard Poodles, and Great Danes. Though fawn (dilute brown) dogs also tend to suffer from the same affection, CDA seems less common in fawns than in blues. Dilute coats also tend to be sparser in general than non-dilutes, with fewer hairs to the inch. In collies there is another type of dilution ("Grey collie syndrome") causing acyclic neutropenia, a disorder of the immune system, which renders them defenseless against infection. Puppies with this affection die within a few weeks unless kept on stringent regimens of antibiotics their whole lives.
- The Genetics of the Dog, A. Ruvinsky and J. Simpson (ed.)
- Ute Philipp, Henning Hamann, Lars Mecklenburg et al. Polymorphisms within the canine MLPH gene are associated with dilute coat color in dogs BMC Genetics 2005, 6:34
- Rare Pug colors
- Cord Drögemüller, Ute Philipp, Bianca Haase, et al. A Noncoding Melanophilin Gene (MLPH) SNP at the Splice Donor of Exon 1 Represents a Candidate Causal Mutation for Coat Color Dilution in Dogs. The Journal of Hereditary, 2007, vol. 98, no5, pp. 468-473.
- Squib and Cracker (two blue Pomeranians of 1897)
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a blue Chow
Photo by Geneva Z. Bailey
A blue Weimaraner (left) and typical mouse-gray Weimaraner (right)
Photos: Alice Anne Heath (left) & Dwight Lyman (right)