Although many people think that buckskin and dun horses are the same, they are in fact two different colors of horse! There are two different genes that cause each color, and this results in some subtle differences between them.
The main difference is that a dun horse will have markings called prehistoric markings. These are shaded or striped areas of the coat more commonly associated with ancient wild horses.
However, it is possible for a horse to carry both the buckskin and dun genes! This combination is very rare, as it requires a very specific set of genetic circumstances to occur. A horse that is both buckskin and dun is called a dunskin!