Grullo or Grulla

Grullo (pronounced "grew-ya" and "grew-yo") is a color of horses in the dun family, characterized by smoky or mouse-colored, unlike a roan which is composed of a mixture of dark and light hairs. A lot of Grullos' ear tips and edging are a darker color and feature Face Masking, which is a face coloring in contrast with the body color. Grullo / Grulla Horses have Leg Barring or Tiger stripes at and above the hock. Same as the Dun, they have a Dorsal Stripe running down the back line.

The world grullo originates from the Spanish word "grulla", which refers to a slate-gray crane. Because of the Spanish origin of the name, some people will refer to a mare as a grulla and a stallion as a grullo.

A grullo horse is a dun with a black base, but is much rarer than red and bay duns. Only 0.7% of quarter horses registered each year with the AQHA are grullo. There are several variations of grullo, referred to as black dun, blue dun, slate grullo, silver grullo, silver dun, or lobo dun.

The most obvious way to tell a grullo is its primitive markings, which are some or all of the following: dark face; cobwebbing around the eyes and forehead; dark mottling on the body; leg barring (sometimes called tiger striping); dark ear tips and edging; dark ear barring; dark shadowing of the neck; dark dorsal and transverse striping; mane and tail guard hairs.