Grullo
Dun on a black base: a mouse-grey body with a black dorsal stripe.

What does this colour look like?
A smoky-grey to mouse-coloured body (no white hairs, unlike grey) with a black head, lower legs, mane, tail and a black dorsal stripe.
- Body
- mouse-grey / smoky grey
- Mane and tail
- black
- Legs
- black
- Skin
- dark
- Eyes
- brown
- Primitive markings
- Yes (incl. dorsal stripe)
How does this colour arise?
A black horse with the dun gene. The black dilutes to mouse-grey, with a dark stripe along the back.
More about the genetics
Grullo = black (E_, a/a) + D. The grey tint comes from diluted black pigment, not from intermixed white hairs. Grullo (male) / grulla (female) is Spanish terminology.
What is this colour often confused with?
- Blue roan
Roan on a black base: a blue-grey barrel with a black head and legs.
- Grey
A grey turns whiter year after year, whatever colour it was born.
- Smoky black
A black horse with a single cream gene; often indistinguishable from ordinary black.
- Dun
You recognise a dun by the dorsal stripe along the back and the primitive markings.
Discover more
Sources: UC Davis Veterinary Genetics Laboratory · UC Davis Veterinary Genetics Laboratory · Sponenberg, D.P. & Bellone, R.R. (Wiley-Blackwell).