Bay is a hair coat color of horses, characterized by a reddish-brown or brown body color with a black point coloration on the mane, tail, ear edges, and lower legs. Bay is one of the most common coat
A bay mare
The horses of the New South Wales Mounted Police show some of the typical variations in the bay color.
A very dark bay horse might appear to be almost black
Dark bay or "brown" horses often have lighter hair around the muzzle, eyes, flanks, and elbow
Seal brown is a hair coat color of horses characterized by a near-black body color; with black points, the mane, tail and legs; but also reddish or tan areas around the eyes, muzzle, behind the elbow
Bay (horse)
…the bay family are quite complex and, at times, disputed. The genetics of dark shades of bay are still under study. The genetic mechanism that produces seal brown has yet to be isolated. Sooty genetics also appear to darken some horses' bay coats, and that genetic mechanism is yet to be fully understood. The…
This horse looks "brown", but the non-black lower legs give him away as a dark liver chestnut.
In rabbits and other species, the black and tan color comes from an allele of the agouti gene called at.