Grullo or Grulla

Grullo - pronounced (grew-yo)
Grulla - pronounced (grew-ya)

Either of the terms are correct in describing the color. AQHA recognizes the color as grullo. The color is the diluted form of black with dun factor. In other words the black color is modified by the dun gene. "Grulla" is the Spanish word for a gray crane which is a slate-gray colored bird.

You may find grullo or grulla definitions in the rule books of different registries under different definitions but for this I will include the AQHA definition:

Body color smoky or mouse colored (not a mixture of black and white hairs, but each individual hair is mouse colored) Usually has a dorsal stripe, shoulder striping or shadowing and black leg barring on lower legs.

Within this definition there are variations of the color often refered to as slate grulla, silver grulla, olive grulla, black dun or wolf dun. The grullo color in the quarter horse is very rare and only about 0.7% of those registered in the quarter horse breed each year are grullo.


One determining factor of the grulla is the primitve markings which can be seen on all duns to some varying extents.