Yesterday I use the pattern on this horse to discuss the way sabino can mimic rabicano. If sabino can mimic the rabicano pattern, then what exactly does a sabino-rabicano look like. Is it any different from the sabinos that have flank roaning and coon tails?
One difference might be the way the roaning organizes itself. Rabicano is known for having a brindled effect. That is a bit different from the diffused roaning that is present on the horse above. Contrast his side with this mare:
In the areas where the white is less concentrated, the brindling is visible. (In my experience with my own mare, whose striping is pictured in the blog header, this trait is often less obvious in photos than it is in person.)
It may be that this trait can help identify the presence of rabicano as opposed to sabino roaning or even the other forms of white body ticking. Rabicanos do seem to brindle more often than other types of ticked horses, though it is hard to know if this is an exclusive trait or not, too.
Another interesting difference with this horse compared to the first one is that the tailhead is more completely white.
Could sabino, which often boosts the white in other patterns, be influencing the amount of white on the tailhead? The frequent assumption is that rabicano is adding white tailheads to sabino patterns. This kind of effect, where sabino amplifies the white of another pattern, is consistent with what we already know sabino does.
This all illustrates the problem with identifying patterns using the tools we presently have. We have pieces of the puzzle, but we do not (yet) have a complete picture. The point at which one pattern begins and another ends is not entirely clear. To make matters more complicated, the evidence suggests that at the more minimal end there is considerable overlap. And at t the other end, the amount of white tends to hide the clues!
Both horses posted are good examples. Not only are they roaned and coon-tailed, but they each have high stockings and one blue eye. Here is the head shot from the mare. (I did not have a good, in-focus head shot of the colt in the first picture.)
Does her blue eye come from sabino, which she obviously has? The white high on the broad side of her neck suggests she also has the frame pattern. Did that give her the blue eye? Is it proof of the presence of splash? Right now we simply do not know for sure. When there are more tests, we’ll probably be able to develop a more clear picture of just where the patterns start and end. But for now it really is just guesswork. Sometimes the breed can eliminate certain possibilities, or more clues can be found by examining production records of a given family of horses, but it is still guessing.