Bay horse color comes when a horse has both one or two copies of the extension gene (E/e, black/red) and the Agouti gene (A/a, restricts black to points), so genotypically they are E? A?
Body color ranges from a light reddish-brown to very dark brown with "black points." (Points refer to the mane, tail, and lower legs). The main color variations are:
* Dark bay: very dark red or brown hair, also called "black bay," "mahogany bay," or "brown."
* Blood bay: bright red hair, the shade variation often considered simply "bay."
* Light bay: lighter than a blood bay, but hairs still clearly more red than gold
* Wild bay: very small black on the legs
The body is mainly brown although the shade of brown may vary from very pale to very dark. The mane and tail are black. The legs are black from above the leg downwards.
