Color Shifting

A visual guide to equine colors and patterns

Black appaloosa with color shifting (negative for known dilution genes)

Close-up of the lower legs of the appaloosa mare shown to the left

Appaloosa color shifting

Silver dilutes the black pigment on the body of the horse to a silvery chocolate color, and turns the mane and tail flaxen. This means that black horses show the effect most strongly. Bay horses have their black legs diluted and flaxen mane and tail, but their red body remains unchanged. Because they do not have black hair to dilute, chestnut horses that have the silver dilution do not show the effect. Because chestnuts with the silver dilution can have self-colored manes and tails, it does not appear that silver alters their manes and tails to flaxen.

Silver-diluted black can vary in color from a pale taupe to a deep chocolate that approaches black. Seasonal changes are common, with winter coats tending to be paler. As they age, the flaxen manes and tails tend to darken, starting at the roots. Black silvers sometimes show dappling. This is especially vivid when the horse is clipped. Paler silvers sometimes have a dark face mask similar to that seen on dun horses.

When combined with cream, silver-diluted black pigment tends to lose its cool, silvery tones and look more like milk chocolate. Black silvers with cream, sometimes called silver smokies, often lack the contrast in their manes and tails seen in ordinary black silvers.

Silver smoky (black silver cream) - notice the warmer tone compared to the two horses above (Positively Charmed, purebred Morgan)

A clipped black silver showing vivid dappling with longer coat is visible at the base of the tail (Miniature Horse)

Other instances of color shifting

Silver can be difficult to identify reliably without genetic testing. Darker silvers, liver chestnuts and sooty palominos can all look very similar. The difference in leg color on clear bay silvers can be subtle, especially in winter, leading them to be misidentified as chestnut. Sooty chestnuts where the dark hairs are concentrated on the legs can be mistaken for bay silvers. Some wild bays have very pale, silvery points and some otherwise ordinary bays have flaxen manes and tails. Black silvers and chestnut-based mushrooms also look very similar.

As silvers age, their manes and tails tend to darken (bay silver Rocky Mountain Horse)

Black silver in pale winter coat, with a face mask (Miniature Horse)

Wild bay horse with silvery points (Paint Horse)

Legs of the horse to the left

Mode of inheritance

Silver is dominant, so at least one parent must be silver in order for the foal to be silver. However, because silver does not alter the appearance of red pigment, a chestnut horse can carry the gene without showing it. This can make it seem that the color skips a generation. The gene is not lethal, so homozygous silvers can be found.

Cause and origins

Silver is caused by a mutation to the PMEL17 gene, also known as SILV. Commercial tests to identify silver horses are available. Research on ancient remains suggest that the mutation dates back to at least to the Iron Age.

The mutation for silver is associated with Multiple Congenital Ocular Anomalies (MCOA), formerly known as Anterior Segment Dysgenesis (ASD). Homozygous silvers are believed to be at higher risk for these eye defects.

Equine Tapestry posts

Silver dilution and eye defects

Discusses a study of silver Icelandics and merle in dogs (Feb 2012)

The limits of visual identification

Flaxen liver chestnut in the Black Forest Horse

What are you hiding?

Explanation of epistasis and chestnut carriers of silver

Buckskin silver

Images of an aged buckskin silver

Scientific studies

A missense mutation in PMEL17 is associated with the Silver coat color in the horse.

Open access

Two SNPs in the SILV gene are associated with silver coat colour in ponies

Abstract only

On silver dapple colour in Estonian Native horse breed

Abstract only

Silver dapple, a unique color variety in Shetland Ponies

One of the earliest papers on the color (1953) - incorrectly describes it as having originated in the Shetland Pony
Partial access

Multiple congenital ocular anomalies in Icelandic horses

Open access

Multiple congenital ocular anomalies syndrome in a family of Shetland and Deutsches Classic ponies in Belgium

Open access

Phenotypic description of multiple congenital ocular anomalies in Comtois horses

Open access

Where it is found

There are four breeds where silver is common: American Shetlands, American Miniatures, Rocky Mountain Horses and Comtois.

Silver is found more rarely across a wide range of breeds. Among the American breeds it is found in the Morgan, Tennessee Walking Horse, Missouri Foxtrotter, Saddlebred, Quarter Horse, Banker Ponies and the Mountain Pleasure breeds. Among the British native breeds it is found in Welsh Mountain Ponies, Highland Ponies, Gypsy Horses and the Shetland Pony. Other breeds include the Australian Ponies, Australian Stock Horses, Dutch Warmbloods, Dutch Harness Horses, Finnhorses, German Classic Ponies, Icelandics, Nordlands, and Estonian Natives.

Appaloosas

Ava Minted Design a grulla mare who is one of the most dramatic cases of shifting

Elegant Design half-sister to the mare above, with a more typical form of color shifting
RHR MityMistic Image a good example of color shifting on the points of a bay

Andrews Black Velvet black mare shifted to a pale pewter

Knabstruppers
Pegasus Vom Niehaus-hof (black fewspot)
Majestic Don Giovanni (fewspot)

Mönchshof's Cinderella (black spotted blanket)

Nørgaards Leonardo (younger) note the tone of the legs compared to the body

Nørgaards Leonardo (older) showing a shift to a more overall bronze coat

Color shifting in Sabino1 horses

JFK - Tennessee Walking Horse stallion registered as chestnut, but produced bay and black foals from chestnut mares

More of JFK - these pictures show him with a cooler, more pewter color
Jackie Os My Sister - registered as chestnut, daughter of JFK

CMs Travelin' Texas Outlaw - black sabino Foxtrotter (also a really good example of how minimally heterozygous Sabino1 can present)

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