Dappling is an almost universally popular aspect of horse color. There are distinct types of dapples with different causes.
For many of us in North America, it is the time of year when many horses are attractively dappled. At a recent show for Quarter Horses, I had the opportunity to get a lot of good images of dappling. Before I share those, however, I thought I would make a post about the different kinds of dapples. There are many reasons why horses have dapples, and each type can look a bit different.
This is the most familiar form of dappling. It occurs as part of the greying process, which means that it is a temporary phase that some grey horses go through while turning white-grey (like the guy to the left of this vividly dappled pony) or, for some, fleabitten grey.
Some horses that are genetically black silver develop high-contrast dappling patterns. This is why early American Shetland breeders began calling the color "silver dapple." Not all black horses with the silver dilution show dappling, and some of the most striking examples are the result of clipping (see below). However, as the above photo of a black silver Miniature mare shows, some show dapples even in winter coat.
Sooty dappling has a slightly different appearance from other dappling patterns. While most dapples look like lighter spots in the coat, sooty dappling looks like a dark overlay on top of the body color. Although sooty horses can have an all-over dappling pattern, the most common area to see this is the neck, withers and shoulders. Sooty overlay dappling tends to be most extensive (and vivid) in palomino and buckskin horses and quite uncommon in chestnut horses.
For horses with the mealy (pangare) pattern, the area where the most intense red tones transition to the paler parts of the coat often show dappling. This type of dappling is particularly common in some draft horse breeds. It is also one of few forms of dappling that routinely produces a lot of contrast on chestnut horses.
Some horses develop dapples with seasonal changes in their coat. This is particularly true of palomino and buckskin horses, but it also occurs in some horses with roany phenotypes. Visually, seasonal dapples are different from sooty overlay dapples. Instead of a dark charcoal gray "frame" forming the dapples, there is a more intense version of the color found inside the dapple. To see this difference, compare the top left box in the first image at the top of this post with the one directly underneath. Both are images of dappled palominos, but the first is the seasonal color of a clear golden horse, while the second is a sooty palomino.
Horses that have been clipped will sometimes display a dappled pattern. Silver and cream dilutes often have very pronounced dappled patterns after they are clipped—even if the unclipped coat was not dappled. Look for a triangle of longer hair at the tailhead to check if a dappled pattern is due to clipping (see above). Other areas where clipping lines can sometimes be seen are the tops of the forelegs or the base of the mane. Clipper dapples can be soft in outline like those pictured on this black silver Miniature, more distinct like those on the buckskin hunter pony in this post, or even reversed.
Where sooty dappling looks like a dark overlay on top of the coat, condition dapples look like a lighter "glow" coming up from within. They are more subtle than all other types of dappling save reverse dappling (see below). Because their visibility varies depending on the light, they can be challenging to capture in pictures accurately.
Reverse dapples have centers that are darker than the surrounding coat rather than lighter. They tend to be even more subtle—and difficult to photograph—than condition dapples. They are most common on dark-headed roans and champagnes, though they can occur on any color.
If you would like more information, this 2016 article written for equine artists has details about the visual differences between the different types of dapples.