What color is a gray horse known to progressively change into as it ages?

A gray horse is known to progressively change into a lighter shade, often appearing white as it ages. This transformation occurs because the gray coat pattern involves a gene that causes the horse to lose pigmentation over time. As the horse matures, the individual hairs that make up its coat become increasingly white, leading to a largely gray and eventually white appearance.

While gray horses start with a darker gray coat, they will gradually lose their color until they appear nearly white, though the skin underneath retains a darker pigmentation. This characteristic is unique to gray horses and distinguishes them from horses of other solid colors, which do not undergo a similar transformative process in their coat color as they age.