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Montage showing the coat variation of the dog.

The coat of the domestic dog (Canis lupus familiaris) refers to the hair that covers its body. A dog's coat may be a double coat, made up of a soft undercoat and a tougher topcoat, or a single coat, which lacks an undercoat. Double coats have a top coat, made of stiff hairs to help repel water and shield from dirt, and an undercoat to serve as insulation.[1] The terms fur and hair are often used interchangeably when describing a dog's coat, however in general, a double coat, e.g., like that of the Newfoundland and most mountain dogs, is referred to as a fur coat, while a single coat, like that of the Poodle, is referred to as a hair coat.

Contents

GeneticsEdit

 
Newfoundland lying next to its combed-out seasonal undercoat.

There are a greater variety of coat colors, patterns, lengths and textures found in the domestic dog than in its wolf relations, as is typical of all domestic animals. In the wild, mutations often put animals at some practical disadvantage decreasing survival or reducing their attractiveness to the opposite sex; whereas domestic animals are protected from harm, and bred from specifically due to practical applications of the mutation for human uses, or to the attraction man has for uniqueness.

During evolution of the dog from their wild wolf ancestors, coat colors in dogs were probably the inadvertent outcome of some other selective process (i.e., selection for tameness), and were not likely initially selected for intentionally by humans.[2] Research has found that tameness brings associated physical changes, including coat colouring and patterning.[3] Diversification of the dog into different types and ultimately separate breeds increased colour variation as factors such as camouflage and visibility aided the dogs’ functionality.

Coat types were selected for, both inadvertently and intentionally, in accordance with factors such as climate, vegetation in the dogs’ working environment, and the need to perform tasks in water.

Domestic dogs often display the remnants of countershading, a common natural camouflage pattern. The basic principle of countershading is when the animal is lit from above, shadows will be cast on the ventral side of the body. These shadows could provide a predator or prey with visual cues relating to the movement of the animal. By being lighter colored on the ventral side of the body, an animal can counteract this, and thereby fool the predator or prey. An alternative explanation is that the dorsal and ventral sides of an animal experience different selection pressures (from the need to blend into different backgrounds when viewed from above and below) resulting in differing coloration.[4]

Nomenclature of colors and patternsEdit

ColorsEdit

The same color may be referred to differently in different breeds. Likewise, a same term may mean different colourations in different breeds.

Brown, chocolate, liver

Brown, chocolate and liver are the most common terms used to refer to the bb-dilution of black pigment to a dark brown. Depending on breed and exact shade, terms such as mahogany, midtone brown, grey-brown, blackish brown are used. Sedge and deadgrass are used to describe the desired Chesapeake Bay Retriever color that resembles "that of its working surroundings" as closely as possible.

Red

Red refers to reddish shades of orange, brown, and tan. Terms used include orange, red-gold, cinnamon, tan, and ruby. Genetically a dog called red is usually a clear sable (with little to no eumelanin tipping on hairs) or a ruddy recessive yellow.

In some breeds, "red" refers to what would usually be called brown, chocolate, or liver. A "red merle" is always a liver-based merle. In Australian Cattle Dogs, blue stands for a densely ticked liver-based colouration with an overall red-grey appearance.

Gold and yellow

Gold refers specifically to a rich reddish-yellow and its variants, whereas yellow can refer to any shade of yellow and tan. Terms used include yellow-gold, lion-colored, fawn, apricot, wheaten, tawny, straw, yellow-red, mustard, sandy, honey, apricot, blond, lemon. Dogs called golden or yellow tend to be recessive yellow, but can also be sable.

Cream

Cream refers to a pale yellowish or tannish colour which can be almost white.

Fawn

Fawn typically refers to a yellow, tan, light brown, or cream dog that has a dark melanistic mask.

With Weimaraners, fawn refers to their typical brownish grey colouration that with other breeds is usually called lilac.

Black

Black is a pure black that can get grizzled as the dog ages, or have a tendency to gain a brownish cast when exposed to the elements.

Blue

Blue is a cool-toned, metallic grey. It typically means a d/d dilution of black pigment, a grey colouration that is grey from birth, but has a wide range of breed-specific meanings.

In Kerry Blue Terriers, Poodles, and Bearded Collies, "blue" refers to colouration that is black at birth and progressively greys out as the dog matures. In Australian Shepherds, Rough Collies, and Shetland Sheepdogs, blue means a blue (black-based) merle. In Australian Silky Terriers, blue means a saddle-type black and tan pattern, where the black parts of the coat progressively fade to a steel grey as the dog matures, and in Australian Cattle Dogs, blue stands for a densely ticked black-based colouration with an overall blue-grey appearance.

Grey

Grey simply means a grey colouration of any shade. It can be used as an alternative synonym of blue, but tends to mean some other type of grey than the d/d dilution of black. Synonyms include silver, pepper, grizzle, slate, blue-black grey, black and silver, steel. Greys of a dusty or brownish cast are often lilac, a d/d dilution of liver, and this colouration does not have much of a commonly recognised name. Across various breeds, it is called lavender, silver-fawn, isabella, fawn, café au lait or silver beige.

In Poodles, a blue is a very slowly fading, very dark steel grey, whereas a silver is a quicker to clear, much lighter grey that can range from a pale platinum to a steel grey. Both are black at birth with minimal markings to indicate future change. Similarly, café au lait is a slower and darker and silver beige a quicker and lighter progressively greying brown, i.e. liver.

White

White: Such a light cream that it is seen and described as pure white, making them distinct from albino dogs. A white dog, as opposed to an albino one, has dark pigment around the eye rims and nose, often coupled with dark-colored eyes. There is often some coat identifiable as cream between the dog's shoulder blades.

PatternsEdit

The same pattern may be referred to differently in different breeds.

 
Liver and tan Australian Kelpie
 
Black and tan Rottweiler
Black and tan, liver and tan, blue and tan: Coat has both colors but in clearly defined and separated areas, usually with the darker color on most of the body and tan (reddish variants) underneath and in highlights such as the eyebrows. Black and brindle and liver and brindle, in which the same pattern is evident with brindling in place of tan, are also possible, but less common.
 
Black and white Border Collie
 
Blenheim (Red-brown and white) Cavalier King Charles Spaniel
Bicolor (also called Two-color, Irish spotted, Flashy, Patched, Tuxedo) Any color or pattern coupled with white spotting. This can range anywhere from white toes and tail tip to a mostly white dog with color around the base of the ears and tail. Some breeds have special names for the color combinations; for example, Cavalier King Charles Spaniel uses Blenheim for reddish brown (chestnut) and white. Irish Spotted or flashy pattern is symmetrical and includes a white chest, white band around the neck, white belly, and white feet or "boots." This pattern is commonly seen in herding dogs, and Boxers, among others. The piebald gene is responsible for this pattern.
 
Black tricolor Entlebucher Mountain Dog
 
Tricolor Beagle
Tricolor: Three clearly defined colors, usually either black, liver, or blue on the dog's upper parts, white underneath, with a tan border between and tan highlights; for example, the Smooth Collie, the Rough Collie, the Papillon, or the Sheltie. Tricolor can also refer to a dog whose coat is patched, usually two colors (such as black and tan) on a white background.
 
Blue merle tricolor Shetland Sheepdog
 
Red merle Catahoula Leopard Dogs
Merle: Marbled coat with darker patches and spots of the specified color. Merle is referred to as "Dapple" in Dachshunds.
 
Tuxedo Lab mix.
 
Tuxedo Collie mix
Tuxedo: Solid (often black) with a white patch (shirt front) on the chest and chin, and white on some or all of the feet (spats.) The tuxedo pattern is common in dogs that carry only one piebald gene (a heterozygous carrier).
 
Harlequin Great Dane
 
Harlequin Great Dane
Harlequin: "ripped" splotches of black on white. The Great Dane is the only breed with this pattern. The term harlequin is also sometimes used to describe a piebald spotting pattern, such as parti-colored poodles.
 
Spotted Dalmatian
 
Spotted mutt in Sinamaica, Venezuela
Spotted Coin-sized pigmented spots on a white background. The spotting on Dalmatians is unique as it involves mutations in at least three different spotting genes.[5]
 
Red-speckled Australian Cattle Dog
 
Liver-ticked German Shorthaired Pointer
Flecked, ticked, speckled: also called belton in English Setters
 
Orange belton (orange and white speckled) English Setter
 
Blue speckled Australian Cattle Dog
 
Densely brindled liver and white Boston Terrier
 
Very sparsely brindled Great Dane
Brindle: A mixture of black/liver/blue/lilac and red/yellow/cream arranged in a vertical "tiger stripe" pattern.
 
Airedale Terrier with large black saddle
 
Norwegian Dunker with merle-affected black saddle
Saddle or blanket: A different color, usually darker, over the centre of the back.
 
Dark orange sable Pomeranian
 
Clear sable Australian Terrier
Sable: Black-tipped hairs; the rest of the hair can be gold to yellow, silver, grey, or tan. The darkness of the coat depends on how much of each hair is black versus the lighter color. Totally clear sables might only have black in their whiskers.

Show coatsEdit

The nature and quality of a purebred dog's coat is important to the dog fancy in the judging of the dog at conformation shows. The exact requirements are detailed in each breed's breed standard and do not generalise in any way, and the terminology may be very different even when referring to similar features. See individual breed articles for specific information.

SheddingEdit

 
A slicker brush with wire bristles, used for removing loose hair from the coat.

Shedding can occur continuously, but in many breeds is strongly influenced by hormones. Seasonal shedders shed most in spring and fall, following an increase or decrease in day length, and least in summer and winter, in response to constant day length. Cold temperatures stimulate hair growth, so that the heaviest shedding is in spring on dogs living in cold climates. Artificial lighting can alter the seasonal shedding pattern of dogs who live indoors. Other hormonal influences include dietary factors, reproductive hormones in intact dogs, and various medical conditions and disorders. Shedding that is done in a short period of time is known as "blowing the coat" or "blowing coat".[6][7] Among the other coat types, dogs with fine silky coats (e.g., spaniels) are generally moderate shedders, those with an intermediate coat texture (e.g., mountain dogs) are generally heavy shedders, and those with thick stand-offish coats (e.g., spitzes) are generally very heavy shedders.

 
The Portuguese Water Dog is an example of a breed with single, low-shedding coat.

"Non-shedding" dogs have greatly-reduced shedding due to alterations to the hair follicle growth cycle:

  • homozygosity for the furnishings (wire) allele - Most breeds with facial furnishings (including ones whose faces are usually shaved removing the furnishings!) are low-shedding, but they must be homozygous, so dogs of mixed wire/non-wire parentage (e.g., terrier crosses or breeds with wire and non-wire varieties) can be heavy shedders. There are a few furnished breeds that shed more (e.g., Old English Sheepdog, Bearded Collie, Briard, Otterhound);
  • at least one copy of the single-coat (non-shedding) allele - Most dogs with a smooth coat are low shedding, as well as the fringed or flat coat. There are breeds with a very short coat that shed more (e.g., Basset Hound, English Bulldog, Pug, Toy Fox Terrier, Dalmatian, Vizsla, German Shorthaired Pointer);
  • single coat (no undercoat) plus furnishings (homozygous) - These breeds shed the least (e.g., Poodle, Soft-coated Wheaten Terrier). No exceptions.

Hypoallergenic coatEdit

Some dog breeds have been promoted as hypoallergenic (which means less allergic, not free of allergens) because they shed very little. However, no canine is known to be completely nonallergenic. Often the problem is with the dog's saliva or dander, not the fur.[8] Although breeds such as poodles, bichons, yorkies, and wire-haired terriers are commonly represented as being hypoallergenic due to reduced shedding, the reaction that an individual person has to an individual dog may vary greatly. In management of dog-related allergies, it has been found that "Factors related to individual dogs seem to influence the allergenicity more than breed..."[9]

See alsoEdit

NotesEdit


ReferencesEdit

  1. ^ "How to Keep Your Dog Warm This Winter". Spoiled Pets Shop. 2014. Retrieved November 10, 2014. 
  2. ^ James Serpell, ed. (1995). The Domestic Dog: Its Evolution, Behaviour and Interactions with People. Cambridge, United Kingdom: Cambridge University Press. p. 284. ISBN 0-521-42537-9. 
  3. ^ Lyudmila N. Trut (March–April 1999). "Early Canid Domestication: The Farm-Fox Experiment". American Scientist. 87 (2): 160–169. doi:10.1511/1999.2.160. 
  4. ^ Graeme D. Ruxton; Michael P. Speed; David J. Kelly (September 2004). "What, if anything, is the adaptive function of countershading?". Animal Behaviour. 68 (3): 445–451. doi:10.1016/j.anbehav.2003.12.009. 
  5. ^ Edward J. Cargill1, Thomas R. Famula, Robert D. Schnabel, George M. Strain & Keith E. Murphy (July 2005). "The color of a Dalmatian's spots: Linkage evidence to support the TYRP1 gene". BMC Veterinary Research. 1 (1): 1. ISBN 1-74661-481-1. PMC 1192828 . PMID 16045797. doi:10.1186/1746-6148-1-1. 
  6. ^ Blackburn, Sandy (2008). The Everything Dog Grooming Book: All you need to help your pet look and feel great!. Avon, Massachusetts: Simon & Schuster. p. 110. ISBN 1440512140. Retrieved 2017-07-04. 
  7. ^ Dog Fancy (2011). Pug. New York: Lumina Media. p. 36. ISBN 1593788398. Retrieved 2017-07-04. 
  8. ^ Grady, Denise (February 5, 1997). "Nonallergenic Dog? Not Really". New York Times. Retrieved April 3, 2011. 
  9. ^ Heutelbeck AR, Schulz T, Bergmann K, Hallier E (Jan 2008). "Environmental Exposure to Allergens of Different Dog Breeds and Relevance in Allergological Diagnostics". Journal of Toxicology and Environmental Health, Part A. 71 (11–12): 751–8. PMID 18569573. doi:10.1080/15287390801985513. 

Further readingEdit

  • Cunliffe, Juliette (2004). "Coat Types, Colors and Markings". The Encyclopedia of Dog Breeds. Paragon Publishing. pp. 20–23 and various. ISBN 0-7525-8276-3. 
  • Fogle, Bruce (2000). "The Breed Section Explained". The New Encyclopedia of the Dog. Dorling Kindersley. p. 83 and various. ISBN 0-7513-0471-9. 

External linksEdit