From the moment I announced that I was searching for a grulla (which is pronounced “grew-ya”) filly, I was met with looks that said, “Huh?”.

Most people (if they’re familiar with Morgans at all) think that they only come in the standard colors of black, bay and chestnut. NOT TRUE! Morgans can come in an amazing variety of colors, thanks to dilution genes.

Dilution genes take the base coat color and dilute it to some degree. To really simplify things, here’s few examples:

· Bay horse, diluted by one cream gene: Buckskin

· Brown horse, diluted by one cream gene: Brown Buckskin

· Chestnut horse, diluted by one cream gene: Palomino

· Black horse, diluted by one cream gene: Smokey Black

Then we can shake things up a little more, and throw in a second cream gene. That would give us these results:

· Bay horse, diluted by two cream genes: Perlino

· Chestnut horse, diluted by two cream genes: Cremello

· Black horse, diluted by two cream genes: Smokey Cream

Sounds fantastic, right? And it is. But it gets even better when you add the dun gene to the mix! Dun is a dilution gene that lightens both red and black hair on a horse. Because it is a dominant gene, every dun horse must have at least one dun parent. Let’s see what we get now:

· Bay base coat + dun gene: Peanut Butter Dun (or Bay Dun or Zebra Dun)

· Bay base coat + dun gene and one cream gene: Dunskin

· Bay base coat + dun gene and two cream genes: Perlino Dun

· (There’s also a brown dun. Read more about that at Dun Central Station.)

 

· Chestnut base coat + dun gene: Red Dun

· Chestnut base coat + dun gene and one cream gene: Dunalino

· Chestnut base coat + dun gene and two cream genes: Cremello Dun

And now for my favorite part…

· Black base coat + dun gene: Grulla (or Grullo)

· Black base coat + dun gene and one cream gene: Smokey Grulla

PLEASE NOTE: This is a ridiculously simplified view of Morgan color genetics! For a more in-depth and educationally sound explanation, please visit the Morgan Colors, Rainbow Morgan Association and Dun Central Station websites on the Links page. They have wonderful photos of every color under the Morgan rainbow...

So there you have it. A grulla colored horse has a black base coat that has been diluted by the dun gene. Grullas can range from a dark mousy gray all the way to a light, silvery gray. Traditionally their heads will be a darker shade than their bodies, and they will have “Dun Factor” markings. Dun Factor markings include leg barring, dorsal stripes, cobwebbing, wither stripes and dorsal barbs.

Remember: just because a horse might have a dorsal stripe, that does NOT make it a dun! If there is no dun parent, you cannot have a dun, no matter how convincing that stripe looks. Several other colors can produce countershading that mimics a true dun dorsal.