Last updated: October 14, 2025
At the 2025 Lafayette Quarter Horse show, I watched a tan mare run barrels. At first I couldn’t tell if she was a buckskin or dun. However, after she stopped her dorsal stripe was clear as day, and up close, her leg barring confirmed she was no buckskin. After 25 years with horses, a true dun horse still gets me excited.
People ask me all the time if their horse is a real dun—it’s not always obvious. Dun horses carry ancient genetics that dilute coats and add primitive markings, like leg barring seen on wild Mustangs, from light red duns to smoky grullos.
This guide covers everything you need to know about dun horses: identifying leg barring and other markings, genetics, buying, and care, all from my hands-on experience. Got a dun story? Share it below! For more on equine colors, check my article on horse coat colors.
What Is a Dun Horse?
A dun horse carries the dominant D gene (TBX3 mutation), which dilutes the base coat color and adds distinctive primitive markings, per the American Quarter Horse Association. This gene lightens bay, black, or chestnut coats and produces markings like a dorsal stripe, zebra stripes on the legs, shoulder barring, dark ear tips, and darker lower legs.
Unlike grays, which lighten with age, or buckskins, which lack primitive markings, dun foals are born with their diluted coat and markings that stay consistent for life. The D gene carries no major health risks, unlike some color genes.
Key Identifiers of True Dun Horses
- Sharp dorsal stripe running from mane to tail (never seasonal or fuzzy)
- Zebra stripes on legs, most prominent on forearms and gaskins
- Darker face and points than the diluted body color
- Born with dilution (not developing over time like grays)
- Shoulder barring or cobwebbing patterns (in some duns)
Dun markings tie these horses to their ancient roots, likely serving as camouflage in the wild. You’ll see them in feral Mustang herds, especially Kiger Mustangs in Oregon, where nearly half carry dun genes (BLM).
For context on base colors, check our guides on chestnut horses and bay horses.
Dun vs. Buckskin vs. Palomino: How to Tell Them Apart
Distinguishing dun horses from buckskins and palominos is a common challenge I’ve seen in my 25 years with horses. Here’s a clear comparison to help you spot the differences:
Use this quick reference when evaluating a horse:
| Marking | Dun Horse | Buckskin | Palomino | Roan |
|---|---|---|---|---|
| Dorsal Stripe | ✔️ | ❌ | ❌ | ❌ |
| Leg Barring | ✔️ | ❌ | ❌ | ❌ |
| Shoulder Shadow | ✔️ | ❌ | ❌ | ❌ |
| Ear Tips | ✔️ | ❌ | ❌ | ❌ |
| Ventral Stripe | ✔️ | ❌ | ❌ | ❌ |
| Color Type | Gene | Base Color | Appearance | Primitive Markings? |
|---|---|---|---|---|
| Dun | D gene (TBX3) | Any (bay, black, chestnut) | Tan to smoky gray coat with dark points | Yes — dorsal stripe, leg barring (aka zebra stripes) |
| Buckskin | Cream (CR) gene | Bay only | Golden coat, black mane/tail | No |
| Palomino | Cream (CR) gene | Chestnut only | Gold coat, white mane/tail | No |
Foolproof Identification Method
- Check for primitive markings first: Duns always have a dorsal stripe and usually leg barring (aka zebra stripes)
- Examine leg barring: Horizontal dark stripes on legs = dun; no stripes = buckskin/palomino
- Look at mane/tail color: Duns have darker points; palominos have white manes/tails
- When uncertain, test: UC Davis or Animal Genetics can confirm genotype ($40–$60)
For more, see our Dun vs. Buckskin guide.
Dun Horse Genetics
Dun horses stand out with their diluted coats and primitive markings, like leg barring and dorsal stripes, tied to ancient ancestry. The dominant D gene (TBX3 mutation) dilutes the base coat (bay, black, chestnut) and adds sharp markings, per UC Davis Veterinary Genetics Laboratory (95% accurate, 2024). Horses with at least one D allele (D/D, D/nd1, D/nd2) show dun traits; non-dun alleles (nd1, nd2) produce no dilution and faint or no markings.
Dun Genetics and Inheritance
| Genotype | Phenotype | Breeding Outcome (D/d1 Cross) | Dun % |
|---|---|---|---|
| D/D | Dun: Diluted coat, sharp leg barring, dorsal stripe | 100% dun (D/D or D/d1) | 100% |
| D/nd1 | Dun: Diluted coat, sharp leg barring, dorsal stripe | 50% dun (D/D or D/d1), 50% non-dun (d1/d1) | 50% |
| D/nd2 | Dun: Diluted coat, sharp leg barring, dorsal stripe | 50% dun (D/D or D/d2), 50% non-dun (d2/d2) | 50% |
| nd1/nd1 | Non-dun1: No dilution, faint markings possible | 50% dun (D/d1), 50% non-dun (d1/d1) | 50% |
| nd1/nd2 | Non-dun1/2: No dilution, faint markings possible | 50% dun (D/d2), 50% non-dun (d1/d2) | 50% |
| nd2/nd2 | Non-dun2: No dilution, no markings | 50% dun (D/d2), 50% non-dun (d2/d2) | 50% |
Subtypes:
- Red Dun: Chestnut base, apricot coat, red leg barring.
- Grullo: Black base, smoky gray, black leg barring.
- Bay Dun: Bay base, tan coat, black leg barring.
Testing via UC Davis ($40–$60, 2025 prices) predicts foal colors. See our equine genetics guide for more.
Dun Subtypes by Base Color
- Red Dun (Chestnut Base + D Gene): Apricot to peachy body with red to dark red mane, tail, and leg barring (aka zebra stripes)
- Grullo (Black Base + D Gene): Smoky gray to mouse-colored body with black mane, tail, points, and leg barring
- Bay Dun (Bay Base + D Gene): Light tan to sandy body with black mane, tail, lower legs, and leg barring
Dun Horse Colors & Patterns
Dun horses come in a variety of shades, each influenced by their base coat color and the action of the dun gene. The table below highlights the most common dun color variations, their descriptions, and visual examples.
| Color | Description | Image |
|---|---|---|
| Bay Dun | Tan with black points |   |
| Red Dun | Apricot with red points |   |
| Grullo | Mouse gray with black points |   |
| Dunalino | Palomino base with dun gene |   |
| Dunskin | Buckskin base with dun gene |   |
| Smoky Black Dun | Black base with dun gene |   |
| Silver Dun | Silver dilution and dun gene |   |
Primitive Markings: Ancient Heritage in Modern Horses
Primitive markings set dun horses apart from all other coat colors, reflecting their prehistoric heritage. These patterns are the definitive identifiers of true dun coloration, linking modern horses to their wild ancestors.
Types of Primitive Markings
- Dorsal Stripe: A sharp, dark stripe from withers to tail, always present in true duns, never fuzzy or seasonal.
- Leg Barring (aka Zebra Stripes): Horizontal dark stripes on legs, most prominent on forearms and gaskins, sometimes wrapping fully around.
- Shoulder Barring/Cobwebbing: Cross-stripes or web-like patterns across shoulders and withers, ranging from distinct lines to subtle webs.
- Ear Tips and Frosting: Dark ear edges and light “frosting” around the muzzle, subtle but consistent markers.
- Ventral Stripe: A rare dark stripe along the belly, seen in some duns.
The Ancient Connection
These markings, seen in prehistoric cave art like France’s Lascaux caves, reflect camouflage patterns that aided wild horses’ survival. Leg barring broke up their outline in tall grass, while dorsal stripes mimicked shadows in rocky terrain.
Today, feral Mustangs, especially Kiger Mustangs in Oregon, retain these traits, with up to 30% carrying dun genes. The Norwegian Fjord Horse Registry requires these markings for breed authenticity.
Dun Horse Breeds: Where to Find These Ancient Colors
The dun gene can appear in any horse breed, but certain populations—like those shaped by natural selection or selective breeding—show higher frequencies of this ancient coloration.
American Quarter Horse
- Frequency: ~10% of registered Quarter Horses carry dun genes.
- Popular Uses: Ranch work, reining, cutting, western pleasure
- Notable Bloodlines: Hollywood Dun It descendants, prized for dun traits
- Registry: AQHA recognizes red dun, grullo, and bay dun as distinct colors
Mustang
- Frequency: 20–30% in feral populations, up to 50% in Kiger Mustangs.
- Characteristics: Prominent leg barring and dorsal stripes from natural selection
- Availability: BLM adoption programs regularly feature dun Mustangs
- Temperament: Hardy, intelligent, excellent under saddle with training
Norwegian Fjord
- Frequency: ~90% of the breed displays dun coloration
- Unique Features: Two-toned mane with dark center stripe, traditionally roached
- Breed Standard: Primitive markings required for Norwegian Fjord Horse Registry
- Temperament: Gentle, reliable, strong work ethic
Other Notable Breeds
- Highland Pony: ~30% dun frequency, often grullo shades
- Icelandic Horse: ~10% carry dun genes, valued for hardiness
- Appaloosa: <5%, striking dun + spotted combinations
- American Paint Horse: Occasional duns with vivid color patterns
- Sorraia: ~50% dun frequency, known for primitive grullo coats
Famous Dun Horses: Legends and Icons
Dun horses have left their mark in competition arenas and popular culture, showcasing the beauty and strength of this ancient coloration.
Real Champions
- Hollywood Dun It: This red dun Quarter Horse stallion revolutionized reining, earning AQHA Hall of Fame status and siring over 500 foals who earned over $8 million in competition.
- Dun Deal: AQHA World Champion, proving dun horses excel in western performance at the highest levels.
- Smart Little Lena Offspring: Many dun descendants of this cutting horse legend continue to dominate competitions.
Fictional Fame
- Spirit: The Kiger Mustang stallion from DreamWorks’ “Spirit: Stallion of the Cimarron,” with prominent primitive markings, showcased dun horses’ wild beauty to millions.
- Hidalgo: The dun Mustang from the 2004 film “Hidalgo,” known for his endurance and striking leg barring, inspired audiences with his grit.
These horses show dun coloration isn’t just stunning—it’s built for elite performance. Hollywood Dun It and Spirit highlight how primitive markings shine in both arenas and on screen.
Watch this short video to see the distinctive primitive markings of a dun horse in action:
Caring for Dun Horses: Special Considerations
Caring for dun horses follows standard equine practices with color-specific considerations, especially for lighter duns in sunny climates like Louisiana.
Skin Care and Sun Protection
In Louisiana’s intense sun, light-colored duns—like red duns and pale bay duns—need extra UV protection due to their diluted coats offering less natural shielding than darker horses.
- UV Protection Essentials:
- Fly masks with UV protection: $50–$100, like Sunny Zebra.
- Lightweight UV fly sheets: $80–$150 for full coverage
- Equine sunscreen for pink areas: $20–$30, such as Ultimate SunShield spray
Regional Climate Considerations
- Desert climates (Arizona, Nevada): High UV protection needs, $200–$400 annually (2025 retail prices)
- Northern regions (Montana, Minnesota): Less intensive sun protection, $50–$150 annually
- Humid climates (Louisiana, Florida): Use breathable UV gear to prevent overheating
Grooming to Enhance Dun Coloration
Proper grooming makes primitive markings pop:
- Daily brushing: Enhances contrast between diluted body and darker markings
- Whitening shampoo: Brightens red duns’ lighter areas without affecting leg barring (aka zebra stripes)
- Gentle curry combs: Avoid over-scrubbing leg barring to prevent irritation
- Show preparation: Use coat polish sparingly to preserve natural color variations
For detailed grooming tips, see my Daily Horse Grooming Guide.
Nutritional Support for Coat Health
- Biotin supplement: 20mg daily I use biotin from Horse Health) for coat strength
- Flaxseed oil: 4–8 oz daily for skin health and coat luster
- Quality hay and pasture: Essential for vibrant coat color
- Adequate water: Critical for skin health, especially for light duns
Health Monitoring
Dun horses are generally healthy, but watch for:
- Sunburn on light areas: Especially muzzles, pink skin around markings, and diluted body areas
- Norwegian Fjords: Monitor for laminitis due to sturdy build and metabolic traits
- Regular veterinary care: Standard preventive schedule as for any horse
- Skin cancer screening: Annual checks for horses with pink skin areas
On one particularly hot summer trail ride, my red dun mare came back with a nasty sunburn on her pink muzzle despite my precautions. Now I never skimp on UV protection—it’s much cheaper than the treatment.
Dun Horse Costs: Investment and Ownership
Owning a dun horse is a rewarding investment, but understanding the costs helps you plan and avoid surprises. Here’s a breakdown based on 2025 market conditions.
Purchase Prices by Breed and Quality
| Breed Type | Price Range | Factors Affecting Price |
|---|---|---|
| Quarter Horse Dun | $3,000–$20,000+ | Training level, bloodlines (Hollywood Dun It lineage premium), conformation, age |
| Mustang Dun | $500–$2,000 | BLM adoption ($125–$500) vs. gentled horses, Kiger bloodlines premium |
| Norwegian Fjord | $5,000–$15,000 | Import costs, breeding quality, training, traditional markings |
| Highland Pony | $3,000–$8,000 | Rarity in US market, import considerations, size |
| Appaloosa Dun | $2,500–$12,000 | Combination markings, bloodlines, athletic ability |
Annual Care Costs (Louisiana Estimates)
| Expense Category | Annual Cost | Notes |
|---|---|---|
| Feed (hay, grain, supplements) | $1,000–$1,800 | Varies by region; biotin for coat health adds ~$100 |
| Veterinary Care | $400–$700 | Routine care, vaccinations, dental; emergency fund advised |
| Farrier Services | $300–$600 | Every 6–8 weeks; rocky terrain may require shoes |
| Insurance (optional) | $300–$500 | Major medical/mortality; higher for valuable breeding stock |
| UV Protection Gear | $100–$200 | Fly masks, sunscreen for light duns’ pink skin and diluted areas |
| Boarding (if applicable) | $2,400–$9,600 | $200–$800/month depending on location and services |
For detailed ownership costs, see my Horse Ownership Costs Guide.
Breeding Dun Horses: Planning Your Program
Breeding for dun coloration combines genetics and market savvy to produce stunning foals with primitive markings. Here’s what successful breeders need to know in 2025.
Genetic Testing Before Breeding
Genetic testing is critical to ensure dun offspring and avoid surprises:
- Test both parents: Use UC Davis or Animal Genetics ($40–$60 per test, 2025 prices)
- Homozygous vs. heterozygous: D/D horses guarantee 100% dun foals; D/d gives 50–75% dun odds
- Base color genetics: Test for extension (E) and agouti (A) genes to predict red dun, grullo, or bay dun subtypes
- Other color genes: Cream, gray, or pinto genes can interact with dun, affecting coat and markings
In 2024, at a LSU equine breeding clinic, I saw a client’s grullo Quarter Horse mare, produce a homozygous dun foal after careful genetic testing. Her vivid leg barring and smoky coat fetched a premium, proving the value of planning.
Frequently Asked Questions About Dun Horses
Got questions about dun horses? Here are answers to the most common ones I hear, based on 25 years of hands-on experience.
What exactly is a dun horse?
A dun horse carries the dominant D gene (TBX3 mutation), diluting their base coat (bay, black, chestnut) and adding primitive markings like a dorsal stripe and leg barring (aka zebra stripes). These markings set duns apart from other colors.
How can I tell a dun from a buckskin?
Duns have primitive markings, like a sharp dorsal stripe and leg barring on their legs. Buckskins, from the cream gene on a bay base, have golden coats with black points but no leg barring. See our Dun vs. Buckskin guide for details.
What’s the difference between red dun and grullo?
Red dun comes from a chestnut base with the dun gene, giving an apricot coat with red points and leg barring. Grullo (or blue dun) is a black base with the dun gene, producing a smoky gray coat with black points and primitive markings.
Are dun horses prone to health problems?
Generally, no. Dun horses are as healthy as other colors. Light duns, like red duns, need UV protection for pink skin around markings to prevent sunburn in sunny climates like Louisiana, but the dun gene has no health risks.
Do all horses with dorsal stripes have the dun gene?
No. True dun dorsal stripes are sharp, with leg barring and other primitive markings. Non-dun horses may show fuzzy countershading or seasonal stripes that fade. Test via UC Davis ($40–$60, 2025 prices) to confirm.
For more horse color info, see our guides on chestnut horses and white horses.
Myths vs. Facts About Dun Horses
Common misconceptions about dun horses can confuse even experienced owners. Here are the facts to set the record straight.
- Myth: Dun is a horse breed.
- Fact: Dun is a coat color pattern found in many breeds, like Quarter Horses and Mustangs. Norwegian Fjords are bred for dun coloration, but the dun gene appears across breeds.
- Myth: All horses with dorsal stripes are duns.
- Fact: True dun dorsal stripes are sharp, with leg barring (aka zebra stripes) and other primitive markings. Non-dun horses may have fuzzy countershading stripes that fade seasonally. Test via UC Davis to confirm.
- Myth: Grullo horses are just dark grays.
- Fact: Grullos have black-based coats diluted by the dun gene, with leg barring and primitive markings. Gray horses carry the progressive gray gene, lightening over time without zebra stripes.
- Myth: Dun horses are always wild or feral.
- Fact: While primitive markings link duns to wild ancestry, domestic duns excel in reining, cutting, and driving, like Hollywood Dun It’s show-stopping offspring.
- Myth: You can’t breed for specific dun colors.
- Fact: Testing base color genetics (E, A genes) predicts dun subtypes, like red dun or grullo. A chestnut mare and black dun stallion can yield both, with 75% dun odds from D/d × D/d parents, per our genetics section.
In 2024, at a Lafayette horse auction, I overheard a buyer call a grullo colt a “gray.” His sharp leg barring and smoky coat screamed dun, but the myth cost him a bid. A quick UC Davis test later confirmed the colt’s D/d status.
Conclusion: The Enduring Appeal of Dun Horses
Dun horses represent a fascinating blend of ancient heritage and modern performance ability. From the peachy coat of a red dun Quarter Horse working cattle in Louisiana to the smoky elegance of a grullo Mustang running free on the range, these horses carry genes that connect them directly to prehistoric equines while excelling in today’s competitive arenas.
Whether you’re drawn to the striking zebra stripes that define primitive markings, the diverse color variations from red dun to grullo, or simply the living history these horses represent, duns offer something special for every horse enthusiast. Their combination of beauty, hardiness, and performance ability makes them valuable additions to any barn.
Key takeaways for anyone interested in dun horses include understanding their genetics (the dominant D gene creates both color dilution and primitive markings), recognizing the importance of those zebra stripes for proper identification, and planning for slightly higher care costs due to UV protection needs in sunny climates. From Hollywood Dun It’s reining legacy to the wild Mustangs still roaming free with their ancient markings intact, dun horses continue to capture hearts and turn heads wherever they go.
For more information about horse colors and genetics, explore our complete Horse Coat Colors Hub, or dive deeper into related topics like equine color genetics.
Have you encountered a memorable dun horse? Share your stories and photos in the comments below—I’d love to hear about your experiences with these remarkable living links to our horses’ ancient past!
🧠 Quiz: How Well Do You Know Dun Horses?
Test your dun horse knowledge! Select the best answer for each question and click Submit.
References
- UC Davis Veterinary Genetics Laboratory – Dun gene testing and comprehensive coat color panels
- Animal Genetics – Equine color testing services and genetic analysis
- Norwegian Fjord Horse Registry – Breed standards and primitive markings requirements
- American Quarter Horse Association – Color registration requirements and genetic testing
- Bureau of Land Management – Wild horse and burro adoption program
- Brooks, S.A., et al. “Morphological variation in the horse: defining complex traits of body size and shape.” Animal Genetics 41.s2 (2010): 159-165.
- Imsland, F., et al. “The dun gene in the Icelandic horse.” Animal Genetics 37.3 (2006): 279-280.
About Miles Henry
Racehorse Owner & Author | 30+ Years in Thoroughbred Racing
Miles Henry (legal name: William Bradley) is a Louisiana-licensed owner
#67012.
Beyond the racetrack, he’s cared for Quarter Horses, Friesians, Paints, and trail mounts for 30+ years—bringing hands-on experience to every breed profile, health guide, and gear review on this site.
His racehorses have finished in-the-money in
30 of their last 90 starts
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