Cedar Ridge, Grullablue, grullo, grulla, blue roan, quarter horses, AQHA, reining, Hancock, Blue Valentine, Hollywood Dunit, Topsail


Grullo or Grulla

Explained in as simple of terms as possible!

April, 2018:  Much of this page is very old, and needs to be updated. Some of the info is outdated, but it is still a good reference for the most part. I'll try to update it soon!

Three different shades of grulla, sunbleached (late summer)

Copyright and "Up to Date" Note:

Please note that all of the text information on this page was originally composed by me unless otherwise referenced, and was typed with great thought.  I have read books and many educational web sites to contribute to my knowledge base.  Some of the content was created in the late 1990's, and may need to be updated. With 300+ pages in this web site, I can't remember which pages need updates all the time. If you see an out-of-date page, let me know so I can update it.

Some photos were donated by people that have horses with color examples needed to provide educational content. For that reason, permission is not granted for anyone else to use photos from these pages.

Please feel free to link to this page, but do not copy the content and place it on your site.

"UP TO DATE" Note:  Some of the color/informational pages on my site have not been updated for a long time due to my lack of free time to do so. 
I am leaving the pages up because they are still helpful. BUT, some of the terminology is incorrect and there is also NEW knowledge available regarding color genetics. Some day, I will update these pages...when time allows.

Click here to learn more.

  [Definition] [Finding a Grullo] [Silver Grullo] [Foal Colors] [Grullo Links] [Genetics] [Request Color Help]

Grullo (pronounced "grew' yo" or "grew' ya") is a fairly-rare color still for AQHA horses, even though there are many breeders specifically breeding for the color.

What is a Grullo?

Simplest terms:  A grullo is a black horse with the dun gene.  Grullos range in color from light silvery-white to dark chocolate brown, and some almost look black.  

Grullos MUST have the following characteristics:

  • Black or brown legs

  • The head will be darker than the body

  • Dark tips on the ears

  • A very DISTINCT dorsal stripe that runs fully from the base of the mane and into the tail

Grullos will often have other characteristics such as:

  • Stripes on the legs (leg bars)

  • Mottling on the upper legs, shoulders, gaskins

  • Dark rings around the ears

  • Striping on the forehead (cobwebbing)

  • Stripes crossing the back, shoulders, or neck

Grullo is the result of the dun factor "gene" on a black horse.  Grullo (used here for both masculine, and the feminine "grulla") is to black as dun is to bay, and as red dun is to sorrel.  They are just the colors that result when the dun factor is applied to the base coat colorsThis dun gene acts similarly to the creme gene in that it dilutes the base color, but not quite the same.  The following table shows what color results from three base horse coat colors when the dun or creme genes are passed by a parent to an offspring.  Back to Top

Base Color Base Color plus Dun Gene (always has a dorsal stripe) Base Color plus Creme Gene
Sorrel Red Dun Palomino
Bay Dun Buckskin
Black Grullo Smoky black (brownish)

Combinations of the above colors, and others, exist.  For example, see Baileys Badland Buck, a palomino red dun (dunalino).  She carries both the creme and the dun genes on a base sorrel color.  Our late stallion, Blue Yahooty Hancock, is a base color black with the dun gene (making him grullo) AND the roan gene (making him a blue roan).  Most of the year, he looks grullo, but for a couple months of the year he is a blue roan with a dorsal stripe.  The same is true with Crowheart WYO Boy.

Genetics of the Grullo Color

  Back to Top

How Can I Get a Grullo?

  1. Buy One.  Your best bet is to buy one from a reputable breeder who specializes in grullos (like us) if you want a foal, or to buy a mature grullo whose color is easy to determine.  Non-grullo specialists (breeders) often "think" they have a grullo foal, but the buyer ends up with a dun, gray, or a black in many cases.

  2. Make One.  The other way is to try to breed for one.  There are few guarantees on this route, but with genetic testing, some people have been able to match up stallions and mares to produce grullo foals 100% of the time.

To have a grullo foal, the best bet is to breed two grullos, or even to breed a black to a grullo.  The chance of having a grullo foal from two grullo parents has averaged less than 50% in some studies, but can be 100% in certain circumstances (with certain homozygosities).  This varies, depending upon whether the dun factor and/or the black gene (lack of red factor) are homozygous in the sire and/or the dam, however. 

Back to Top

[Definition] [Finding a Grullo] [Silver Grullo] [Foal Colors] [Grullo Links] [Genetics] [Request Color Help]

The Elusive Silver Grullo

Many people are looking for a silvery-colored grulla, and many breeders claim to have them. 

If you are looking for a silvery grulla foal, educate yourself.

If you see a newborn foal that is silver-colored, you can very often get a resulting horse that is black, a dark slate or medium slate grulla (or even a gray that will turn white and not even be a grulla at all!) at maturity.  Silvery grulla foals are usually born a VERY light buff/cream color, and not a light gray color.  There are exceptions, but in general, this is true.

True silvery grullas may have blue-gray eyes  according to some sources, but this is generally true only in the foal's early life. This is because one (outdated) definition of a silver grullo is a "grullo that also carries a creme gene." The creme gene usually gives the foal blue eyes at birth, but does NOT guarantee the coat color will be light silver in shade.

Buy cautiously if you are trying to buy a silvery grulla as a foal.  Many breeders advertise "silver grulla foals" who later shed out black or dark grulla.  Your best bet is to visit the farm and look at the under-color of the foal coat, or at the back of the foal's buttocks where it has begun to shed.  Even at that, grullas change so much in their first few years that luck will have to be considered a factor.  The only sure way to buy a silvery grulla is to buy a mature horse that is silver! 

Smokey Grullo and Silver Grullo

Keep in mind that terminology is changing. Until about 2005, the term "silver grullo" was used to describe a silvery-colored grullo (light silvery body color) most of the time. Some people used it to describe any grullo that also carried a cream gene (smokey grullo), whether light/silver shade or dark grullo shaded.

In recent years, "silver grullo" has been used for a grullo that also carries a silver dapple gene. I think that in the future, "silver grullo" will be most correct for grullo + silver dapple horses, and "smokey grullo" will be for grullos with cream genes.

It might be a compromise temporarily to call a light-colored grullo a "silvery grullo" (with the y on the end of silver). Maybe people will begin calling them "light grullos." At this point, it's hard to guess.

A "true" silver grullo: Silver Dapple + Grullo
(aka silver black dun and various other terms)
Note the light mane and tail, which are caused by the silver dapple (aka Taffy) gene.

Back to Top

Examples of Foal Coat Colors  

Grullo foals are often mistaken for dun foals, and even long-time breeders can be fooled.  Grullo foals have even been born red dun, only to shed out grullo within the first year.  Many black foals have been called grulla, only to shed off black around the age of 4 months.  We hope buyers will beware of buying such foals...how disappointing to pay a premium price for a grulla, only to find they have a black later in the year.

Generally, grullo foals are born a light tan color with a distinct dorsal stripe.  

To tell the difference between a grullo foal and a dun foal, look at the face.  Usually, a grullo foal will have black hair around the eyeballs and a black or gray mask of hair across the face/bridge of the nose.  A dun foal will have golden, orange, or brown hair in those two places.  Also, grullos will often have black dorsal stripes, while dun foals will often have dark brown or dark red dorsal stripes.  Still, this doesn't always hold true!  Other grullo foal colors...click here

Grullo Foals

This filly was born silvery and turned into a medium slate.

At birth (left) and at age 2

This filly was born cream/light buff, and looks pretty silvery/light now as an adult.  She had dark blue eyes (at 3 months), instead of brown eyes, which is an indication that she probably carries the creme gene as well as the dun factor. 
21 days old
This filly shed off with a black head and legs, and was a blue grullo base color plus the roan gene.  You can see why some people would have called her a dun, based upon her foal hair color.  5-26butt.jpg (15448 bytes) grulloroanSpark.jpg (13301 bytes)
Left, 2 months.  Right, 6 months
This filly was a unique color.  She shed off a beautiful silvery/light color.  Her parents' colors were inconclusive...a red dun and a dun (possible dunskin).  Thanks for the pictures, Kristi!  :-) karibaby.JPG (12169 bytes)  Kari.JPG (21938 bytes)

Left, foal coat. Right, yearling.

This filly shed off with a medium slate grulla coat which later roaned.  Note the black nose, eye hair, and face mask on her baby picture.  6_week_side.jpg (22813 bytes) july10buttlook.jpg (38704 bytes)
Left, 1 month.  Right, 4 months.
Born silver grullo, this colt changed to a dark slate grullo at maturity.  In the winter, he's a rich, dark charcoal color that's almost black.  He might be a lobo dun (dark grullo).   dundeemature.jpg (10237 bytes)
A bluish-gray eye is characteristic of a dun-factored horse that is also carrying the creme dilution, from my experience.  Often (but not always), these creme carrying grullos will be silver.  NOTE:  Blue eyes are NOT necessarily a characteristic of the dun gene or of grullos in general.  Grayish blue eyes are most likely due to the creme dilution, which is most commonly known for causing buckskins and palominos, and which sometimes appears along with the dun gene, depending upon the ancestors of a horse in question. There are other modifiers that can cause lighter-colored eyes as well.
Creme-carrying silver grullo foal eye color
Click for larger view
THIS IS VERY RARE...do not assume that your red dun foal will turn out to be grullo.  I shouldn't even put this on here, but it is an example of what can happen with colors, and how hard they are to predict.  After having had 50 to 100 grullo foals (I haven't counted), I wouldn't feel badly at all if I was wrong about guessing a foal's color being grullo. They can be tricky! ;-)

This filly was born looking like a red dun, but had black roots to her mane and tail, black skin around her eyes, dark charcoal-colored hooves, and had 2 grullo parents. She grew up to be silvery (light) grullo. 

The last/bottom foal is another example of a grullo that looked red dun-ish at birth, but had dark skin instead of peachy skin. It also matured to a light grullo color, like its dam.

Back to Top

Non-Grullo Horses

This foal is by a palomino sire and a bay dam.  He shed off black, and has now been tested positively as a smoky black.  Pretty deceiving color at birth!  This stripe is attributable to countershading (edit 2018:  nd1 is responsible for foal striping quite frequently, and is now testable). He's gorgeous, either way. tuscarorastablesdotcom.jpg (7392 bytes)
Black or smoky black, not grullo.
This foal (below) was born medium slate/olive (the same color as his dam) and shed off black or smoky black.  His dam was a medium slate grulla with the creme gene, and his sire was black.     
Left--one day old, Right--yearling
Black, not grullo.
This filly is out of a silvery grullo mare and a black stallion.  She had a dorsal stripe at birth and shoulder shading, but ended up being black with no dun or cream genes...just plain black. 
Left, one day old.  Right, yearling.
Black, not grullo.
This is a unique guy!  His dam is a palomino, and his sire is a dun. What a change from his weanling coat (after shedding) to his yearling coat. He's a gorgeous buckskin. smokyblackcolt.jpg (18696 bytes) 
Buckskin, not grullo.
A comparison of a dun and a grulla foal with foal coats on.  Note the colors of the face masks, the hair around the eyes, and the colors of the dorsal stripes.  These are big clues to help determine color.  They aren't 100% accurate, but much of the time will hold true. 
Click to enlarge these photos that show a dun and a grullo next to each other.  The body color is similar, but there are clues that will help you see how to differentiate dun and grullo foals.
A comparison of a sooty buckskin foal and a grullo foal. Note how the buckskin's tail is black to the top, and how the grullo's face has a dark mask over the bridge of the nose between the eyes and the nostrils.
Sooty buckskin left, grullo right. Note the difference in the face colors.
This is a color that is very often incorrectly called grullo. Though it's dark, it is not the same as a dark grullo, and is actually a gorgeous version of buckskin! Notice the yellow tone and the mixture of yellow/gold and black hairs that make the coat dark. This color is caused by a cream gene on a bay or brown coat, possibly with a sooty or smutty modifier added. It is not the same as grullo, which is a dun gene on a black coat.
This foal looked red dun at birth, but had a telltale sign of inheritance of the gray gene by the rich-colored leg hair (as opposed to the dull, buff-colored leg hair that a red dun would usually have). He shed off charcoal color, and could have tricked some into thinking he was grullo. But the mature photo shows that the gray progressed on schedule.
These grays obviously have dun factor (see the leg bars, and dorsal stripe). We know from the graying faces and tails that they have a gray gene. Eventually, they will turn gray and lose their striping, but it sure makes for a neat color combo at this time too!
These are NOT leg bars. This is a black foal with a common hair pattern that some people mistake for leg bars. It is just a hair-direction pattern that eventually goes away.

What color is YOUR foal?

The most common mistake people who contact me
make is in trying to get others to believe
that their foal or horse is the color they WANT him to be.

Many, many people have asked me over the past few years what color their foals were, and then have refused to accept my opinion because they so badly wanted their foal to be a different color.  As you try to figure out your foal's color, leave your personal preference out of it....go by the facts first.  Hopefully, you'll be pleased in the end!  But if not (for example, if you wanted him to be a grulla and he turns out to be a sooty buckskin), take comfort in the fact that you know the truth and can educate others about the differences between similar colors.

[Definition] [Finding a Grullo] [Silver Grullo] [Foal Colors] [Grullo Links] [Genetics] [Request Color Help]

To learn more about grullo and dun colors:

Click here to request help determining your horse or foal's color

  • More about grullo genetics!  This page is about the genetics of grulla, and is more in-depth than this page, but still not full of letters with superscripts and language that is hard to read.  I tried to make this simple, and yet accurate!   Grullo Genetics Info

  • Test your foal or horse...how to be SURE of his/her genetics! 

  • Dun Factor Traits....photos and explanations can be seen  here.

  • Check out http://www.animalgenetics.us/CCalculator1.asp, which is a calculator that will help predict foal color opportunities.

  • Variations of buckskins  Visit http://tenderquarterhorses.tripod.com/tqh_020.htm to learn about sootiness/smuttiness and countershading.

  • He has a dorsal stripe, but neither of his parents did  IMPORTANT LINKS.  This one talks about markings that are similar to dun dorsal stripes, but not the same.  These markings are responsible for a lot of horses being called dun or grulla who really are not. Visit http://tenderquarterhorses.tripod.com/tqh_020.htm to learn about sootiness/smuttiness and countershading.

Click here to request help determining your horse or foal's color

[Definition] [Finding a Grullo] [Silver Grullo] [Foal Colors] [Grullo Links] [Genetics] [Request Color Help] [Top]

How To Donate Your Educational Photo:

  • If you are wondering what color your foal is, click here. We are having a lot of people send us pictures for this page where it is obvious that the foal owners don't know what color their foal is. Please, only send us photos for this page if you know your foal's color. If you don't know what color your foal is, click here.

  • If you foal is a Paint or Appaloosa, we will only use it if the vast majority of the foal's body is not included in the white patterned areas, as this page is intended to help people determine foal colors, so the colored hairs must be very obvious.

  • This is an educational page, and photos should show a safe environment and healthy horses. I don't even know how to respond when I receive photos of wormy, skinny horses in pastures littered with abandoned cars, farm equipment, wire fences laying on the ground, and falling-down buildings. I simply can't put photos like that on an educational page like this, where people come to learn.

  • Please note that this is not intended to be a free opportunity for you to advertise your breeding operation, and instead is an educational page. We will not use photos with watermarks/writing on them. There are many free advertising sites on the Internet at which you can advertise your farm/ranch/horses. Also, only send photos of foals you own. This way, there won't be copyright problems.

Feel free to click the "Send Your Photo" logo at the left
to send a good photo or two to us for inclusion on our color pages.




Photo Ownership Notice:
All of the photos on this page are the property of Cedar Ridge QH's or were sent to us with permission.
If someone has sent a photo to us for use on our pages that belongs to you,
and if they did not have permission to do so, please let us know.
If you are interested in contributing a photo, we thank you! But please do not alter the photo or place your contact
information on it. Our educational pages are for just that...education. Not advertisements. Thanks!

Color and Genetic Testing Labs

There are many laboratories in the US and around the world that do horse color testing, disease testing, etc. When you choose a lab, make sure it is a reputable one! There are several university-related labs, which I recommend, and many private labs (some of which can NOT be recommended!). Here are a few I'm familiar with:

University Laboratories:

Private Laboratories:

  • Animal Genetics, Inc. http://www.horsetesting.com/Equine.asp

  • Pet DNA of Arizona: http://www.petdnaservicesaz.com/Equine.html ONLY tests for Brown in horses (1/2010)

    DNA Diagnostics (aka Shelterwood Labs, and also affiliated somehow with Catgenes.Org)
    http://www.dnadiagnostics.com/  DNA Diagnostics/Shelterwood Labs offers a test for multiple characteristics at one price. I had seen a fair bit of chatter online about how they cash the checks and don't give the results of  the test. So, I tested them by paying for three horse tests. Guess what...they sent back two of my horses' test results and after 4 1/2 months, the third was still missing in action! Repeated phone calls and e-mails were ignored by the lab. Finally, five months after the test, someone gave me the results for the third horse. 
    If you choose to use this lab, my opinion is to only send them as much money as you are willing to lose, in case you don't receive your results. Update: A friend just called that used this lab and she still hasn't received her results after many months of waiting, phone calls, and e-mails. 3/2010. I know of another horse that tested homozygous for black that is not homozygous, as he has produced sorrel and palomino foals. In both cases, Shelterwood does not return their repeated phone calls.


This page last updated 04/03/18
If you notice this date being 2 years or older, please let us know that we need to check out this page!

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Toni Perdew       Bedford, Iowa
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do not call us on the phone with color inquiries for your own horses.
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