grulla

Grulla refers to a color in horses, specifically a shade of grayish or dull dun. This coat color is characterized by a base coat that is typically mouse-gray or a smoky brown, with darker points, such as the mane, tail, and lower legs. A distinctive feature of the grulla coat is the presence of primitive markings, which are common in dun-colored horses. These markings can include a dorsal stripe running down the horse's back, as well as zebra stripes on the legs and a cobwebbing pattern on the forehead.

The grulla color is a dilution of the black base coat gene. This means that a horse must have a black base coat to be grulla. The dilution gene, when present, lightens the black pigment, resulting in the characteristic gray or smoky appearance. This is different from a gray horse, which lightens with age. Grulla is a specific color at birth.

Grulla horses are found in various breeds, though they are particularly associated with breeds that historically worked with cattle or were developed in arid environments, such as the American Quarter Horse, Mustang, and Appaloosa. The color is often seen as a sign of hardiness and an ability to blend into rocky or scrubby terrain. The term "grulla" is Spanish for crane, likely referencing the grayish color of the bird.