The bay horse is brown, while most people immediately think of a bay horse as brown and possibly a little boring I would like to challenge them to stand next to a bay horse in the sun and watch the colors pop. The color variations are incredible. The reflections of the different tones will transform brown to a rainbow of colors right before your very eyes. The bay horse will actually change colors depending on the way the light reflects on their coat. Never underestimate the beauty of a beautiful bay.