INTRODUCTION
Everyone is familiar with a brindled pattern of colouration in domestic mammals.
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However, what remains poorly-appreciated is that this pattern
- has never been produced by natural selection,
- occurs, even in domestic animals, unambivalently in only three spp., and
- differs from the pattern of wildebeests (Connochaetes), which is textural as much as pigmentary.
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Euchromic (purely pigmentary) brindling is unknown in any wild species – including the ancestors of the domestic mammals in which it has emerged inadvertently via anthropogenic selection.
CitedWikipedia
This is puzzling, because brindling
- would hardly look incongruous in a wild mammal, in the ways that other domestic mutations of colouration look asymmetrical, and
- forms the ‘ground-colour’ upon which asymmetrical white markings are superimposed.
CitedWikipedia
SPECIES IN WHICH EUCHROMIC BRINDLING OCCURS
Euchromic brindling has been recorded in only the following spp.:
- Equus caballus,
- Bos taurus, and
- Canis familiaris.
Patterns similar to euchromic brindling occur additionally in
- Felis catus, and
- Cavia porcellus.
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I have yet to find evidence for brindling in
- Bos indicus, despite its close relatedness to B. taurus, and
- Ovis aries and Capra hircus, despite the fact that these spp. are extremely diversified into breeds.
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ILLUSTRATIONS
Equus caballus:
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Bos taurus:
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Canis familiaris:
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Felis catus:
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Cavia porcellus:
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Posted on June 24, 2026 10:59 PM by
milewski
The author added the following in comments beneath the original post.
Chatgpt
MY QUESTION
Certain aspects of adaptive colouration in Nature are purely/solely pigmentational, as opposed to effects such as sheen, gloss, and iridescence. What would be a single technical term meaning ‘purely pigmentational’ in this context?
ANSWER FROM CHATGPT
There is no widely established single technical adjective in zoology or colour science that means exactly “purely pigmentational, without any contribution from gloss, sheen, iridescence, structural colour, or optical effects”.
Several possibilities exist, but each has drawbacks:
Pigmentary — the standard adjective meaning “due to pigment”. However, something can be pigmentary without being solely pigmentary.
Pigmental — occasionally encountered, but uncommon and not generally preferred.
Chromatic — unsuitable, because it refers to colour generally, regardless of mechanism.
Pigment-based or pigment-derived — accurate, but not single-word technical terms.
Non-structural — commonly used in colour science to contrast with structural colour, but it excludes only structural mechanisms and says nothing about gloss or sheen.
If you wish to coin a precise technical adjective, the most etymologically transparent possibilities would be:
pigmentogenic (“produced by pigment”)
pigmental (“of pigment alone”)
chromophoric (“arising from chromophores”), though this term is already used in chemistry and may be too broad.
For zoological descriptions of pelage and plumage, I would favour pigmentary and then define it explicitly on first use:
“The pattern is entirely pigmentary, lacking any structural, catoptric, or iridescent component.”
If a new single-word term is desired specifically to contrast with optical effects such as sheen and iridescence, one could coin euchromic (from Greek εὖ, “truly”, + χρῶμα, “colour”), meaning:
“colour produced solely by pigments and not by optical properties of the integument.”
However, this would be a neologism and would require definition by its author. Among existing terminology, pigmentary is probably the closest and most defensible adjective.
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MY QUESTION
Purely pigmentary brindling does not occur in any wild animal. However, it is common among domestic animals. Which author has explained this, in terms of adaptation and natural selection? Supply full references.
ANSWER FROM CHATGPT
I do not think there is a single author who explicitly argued the precise proposition that purely pigmentary brindling is absent from wild mammals because natural selection eliminates it, whereas it persists in domestic animals because human selection relaxes or overrides natural selection. The argument is usually made more generally, as part of explanations for the extraordinary diversity of coat-colour patterns in domestic animals.
The author who comes closest, and who is probably the strongest citation for the adaptive explanation, is the evolutionary geneticist Leif Andersson. In a major review of pigmentation patterns in domestic animals, he argued that the profusion of unusual colour patterns in domestic forms is primarily due to direct human selection for appearance, whereas many such variants would not be favoured in wild populations because natural selection tends to preserve adaptive colouration and remove conspicuous or non-functional variants.
A second important source is the review by Adam R. Wilkins, Richard W. Wrangham, and W. Tecumseh Fitch on domestication. They emphasised that coat-colour variation is one of the most conspicuous and ubiquitous consequences of domestication, because domesticated populations experience a very different selective regime from their wild ancestors.
For the broader Darwinian principle that animal colour patterns in nature are generally interpreted as adaptations shaped by natural selection, the classic authority is Edward Bagnall Poulton, followed by Hugh Bamford Cott. Neither discussed brindling specifically, but both established the framework in which mammalian colour patterns are viewed as adaptive and therefore subject to natural selection.
A difficulty, however, is that your premise itself is not universally accepted. There is no demonstrated rule that all wild brindle-like mammalian patterns are structurally based and all domestic brindling is pigmentary. The literature on wild mammalian colouration has not, to my knowledge, produced a formal evolutionary treatment of brindling equivalent to what exists for striping, spotting, countershading, or disruptive coloration. Consequently, no major zoologist appears to have published the exact argument in the form you state.
References
Andersson, L. A. (2020). Mutations in Domestic Animals Disrupting or Creating Pigmentation Patterns. Frontiers in Ecology and Evolution, 8, 116. doi:10.3389/fevo.2020.00116.
Cieslak, M., Reissmann, M., Hofreiter, M., & Ludwig, A. (2011). Colours of domestication. Biological Reviews, 86, 885–899.
Kaelin, C. B., & Barsh, G. S. (2013). The role of humans in facilitating and sustaining coat colour variation in domestic animals. Seminars in Cell & Developmental Biology, 24, 587–593.
Poulton, E. B. (1890). The Colours of Animals: Their Meaning and Use. London: Kegan Paul, Trench, Trübner & Co.
Cott, H. B. (1940). Adaptive Coloration in Animals. London: Methuen.
If your interest is specifically the alcelaphin-type phenomenon (the sheen- or texture-based “brindling” of wildebeest, topi, hartebeest, etc.), the most relevant historical author may actually be Richard Lydekker, who repeatedly remarked on the peculiar pelage texture of alcelaphins. That literature is descriptive rather than explicitly Darwinian, but it is probably where the distinction between pigmentary and textural brindling would have to be traced.
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Chatgpt
MY QUESTION
Does brindling occur in any breed of Gallus gallus? Supply full references.
ANSWER FROM CHATGPT
If by brindling you mean the classical mammalian phenomenon—an irregular pattern of darker streaks, bars, or vermiculations superimposed on a lighter ground colour, produced by pigmentation differences in the integument or its appendages—then the answer is essentially no, not as a recognised plumage pattern in domestic chickens (Gallus gallus domesticus).
The extensive poultry-genetics literature recognises plumage patterns such as:
barring,
pencilling,
lacing,
spangling,
mottling,
cuckoo patterning,
partridge patterning,
millefleur patterning,
but not a true brindle pattern homologous to mammalian brindling.
There is, however, one complication. A traditional Czech breed is actually called the Czech Gold Brindled Hen (Czech: Česká zlatá kropenka). Despite the English translation “brindled”, the plumage is not brindled in the mammalian sense. The breed standard describes a gold-and-black speckled or flecked plumage, and the term reflects historical nomenclature rather than the presence of true brindling.
The description of the hens as “gold brindled” appears to be a translation of Czech breed terminology referring to a speckled or mottled plumage pattern rather than longitudinal dark streaking comparable to that seen in dogs, cattle, or alcelaphine bovids.
From the standpoint of avian colour-pattern terminology, chicken plumages that might superficially resemble brindling are usually classified as:
pencilled,
barred,
cuckoo,
stippled,
mottled,
or speckled,
depending on the arrangement of pigment within the feathers.
Consequently, I am unaware of any recognised breed of Gallus gallus domesticus exhibiting true brindling as that term is used in mammalian colouration studies.
References
Breed source
Czech Gold Brindled Hen. Breed account in the Food and Agriculture Organization’s Domestic Animal Diversity Information System (DAD-IS), summarised in: Czech Gold Brindled Hen article.
General definitions of brindling
Merriam-Webster Dictionary. “Brindled”: “having faint dark streaks or spots on a usually gray or tawny ground.”
Encyclopaedia Britannica Dictionary. “Brindled”: “having faint dark streaks or spots on a gray or light brown background.”
If your interest is specifically in whether any chicken breed possesses a texturally generated, sheen-dependent brindling analogous to that which you have been discussing for alcelaphin bovids, then the answer appears to be an even firmer no: I know of no domestic chicken breed in which a brindle-like pattern is produced by directional reflection from differently structured feather tracts rather than by pigment distribution.
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Chatgpt
MY QUESTION
In which breeds of Ovis aries do brindled individuals occur?
ANSWER FROM CHATGPT
If by brindled you mean the true zoological sense—a pattern of irregular dark and light streaking or striping produced by pigment distribution in the coat—then brindling is exceptionally rare in domestic sheep and is not recognized as a standard colour pattern in any major breed of Ovis aries.
The sheep-breeding literature recognizes a wide range of colours and patterns (solid black, brown, moorit, grey, badgerface, mouflon, piebald, etc.), but true brindle is generally absent. Standard breed descriptions for breeds famous for colour variation, such as Shetland sheep, Icelandic sheep, and Soay sheep, do not include brindle as a recognised pattern.
There are, however, scattered reports of individual sheep described as “brindled” by breeders. These fall into three categories:
Rare spontaneous variants within otherwise non-brindled breeds.
Mosaic or chimeric individuals, where different pigment cell lineages create streaked colouration.
Apparitions of “brindling” caused by fleece structure, weathering, or differential fading rather than true pigmentational striping.
I am unaware of any sheep breed in which brindling is:
genetically established,
routinely inherited,
recognised in a breed standard, or
common enough to be considered a breed characteristic.
Consequently, the most accurate answer is:
No breed of Ovis aries is known for a true brindle colour pattern in the way that certain dog, cattle, or guinea-pig breeds are. Brindled individuals may occur sporadically in various breeds, but the pattern is not a recognised characteristic of any sheep breed.
If your interest is specifically in documented photographed examples of genuinely brindled sheep, I can search for individual cases in the agricultural and fleece-colour literature and distinguish them from superficially similar patterns such as badgerface, mouflon, or agouti.
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Chatgpt
MY QUESTION
In which breeds of Capra hircus do brindled individuals occur?
ANSWER FROM CHATGPT
If by brindled you mean a true brindle pattern (irregular dark striping or streaking superimposed on a lighter ground colour, analogous to brindle in cattle or dogs), then the situation in domestic goats is rather different from that in some other livestock.
There is no widely recognised goat breed in which brindling is a standard or characteristic breed trait. Most goat breed standards describe colours such as solid, belted, chamoisée, cou blanc, sundgau, badger-face, spotted, roan, or various piebald patterns, but not true brindle.
That said, brindled individuals are reported sporadically in several breeds and landraces, especially where colour selection is lax. Examples include:
Boer goat — occasional brindle or tiger-striped individuals are reported by breeders, particularly in crossbred populations derived from Boer stock.
LaMancha goat — because virtually any colour and pattern is accepted in the breed, occasional brindle-patterned animals have been recorded by breeders.
Various unmanaged or village goat populations (e.g. in parts of Africa, Asia, and Latin America) may produce animals described as brindled, but these are usually individual colour variants rather than recognised breed characters.
A complication is terminology. Goat breeders often use brindle rather loosely for:
agouti-derived striping,
mixed black-and-brown coats,
heavy ticking,
or irregular streaking produced by piebald genes.
Many purported “brindled goats” therefore are not homologous to the genetically defined brindle of dogs or the classical brindling of cattle.
As far as the zoological and livestock-genetics literature is concerned, I am not aware of any goat breed comparable to brindle cattle breeds (e.g. some Highland or crossbred cattle populations) in which true brindling is a common, breed-defining feature. The standard references on goat breeds generally do not list brindle as a recognised breed colour.
If your interest is specifically in documented photographs of genuinely brindled goats, I can search for published photographic examples and determine which breeds those particular animals belonged to. That would give a firmer answer than breed-standard descriptions alone.
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MY QUESTION
Has brindling colouration been recorded in Equus asinus?
There is no well-established, documented coat-colour phenotype called brindle in the donkey, Equus asinus, comparable to the recognized brindle patterns of dogs, cattle, or some horses.
The modern genetic and breed literature on donkey coat colours repeatedly discusses colours such as dun (the ancestral state), black, chestnut/red, bay, grey, white, spotting patterns, and the “no light points” phenotype, but does not list brindling as a recognized donkey colour pattern.
For example, Royo et al. (2015) explicitly remarked that only a limited range of coat colours, patterns, and textures had been described in donkeys, listing black, bay, grey, red, white spotting, and hair-length variants, but not brindling.
That said, two caveats are necessary:
Individual anomalies may occur. As in horses, localized striping or irregular coat patterning can occasionally arise through developmental mosaicism, chimerism, or hair-growth effects. A photograph of a donkey showing a brindle-like appearance would not by itself demonstrate the existence of a heritable brindle colour morph.
Dun markings can be misleading. Donkeys commonly possess a dorsal stripe, shoulder cross, leg barring, and other primitive markings associated with the dun phenotype. These can superficially resemble brindling to non-specialists but are not regarded as brindle colouration.
So, if the question is whether zoological or livestock literature recognizes a genuine brindled coat colour in Equus asinus, my answer is no: I am unaware of any documented, accepted brindle phenotype in donkeys, and the standard coat-colour literature does not appear to record one.
References
Royo, L. J., et al. (2015). “A missense mutation in the agouti signaling protein gene (ASIP) is associated with the no light points coat phenotype in donkeys.” Genetics Selection Evolution 47: 28.
Wang, C., et al. (2020). “Donkey genomes provide new insights into domestication and selection for coat color.” Nature Communications 11: 6014.
OMIA: “Coat colour, dun in Equus asinus.”
If you are interested specifically in historical breed descriptions, studbooks, or nineteenth-century zoological accounts, I can search those separately; occasionally old authors used the word “brindled” rather loosely for animals that would not now be considered truly brindled.
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Chatgpt
MY QUESTION
In how many breeds of Canis familiaris has brindle colouration been recorded? Supply full references.
ANSWER FROM CHATGPT
There is no published, authoritative count of the number of dog breeds in which brindle has been recorded. The answer depends on what standard you adopt:
Breed standards that explicitly recognise brindle (AKC, FCI, KC, UKC, etc.).
Breeds in which brindle occurs genetically but may be non-standard or rare.
Historically documented occurrences, including accidental or disallowed colours.
Under criterion (2), the number is certainly well over 50 breeds, and probably exceeds 70 if all regional breeds are included. Under criterion (1), the number is lower but still several dozen.
Some breeds in which brindle is formally recognised include:
Boxer
French Bulldog
Bulldog
Bull Terrier
Staffordshire Bull Terrier
American Staffordshire Terrier
Bullmastiff
Mastiff
Great Dane
Greyhound
Whippet
Plott Hound
Dutch Shepherd
Cardigan Welsh Corgi
Basenji
Cane Corso
Kai Ken
Bouvier des Flandres
among many others.
A defensible minimum
If one restricts oneself to breeds whose current major kennel-club standards explicitly permit brindle, a conservative count is approximately 35–45 breeds worldwide. If one includes breeds in which brindle is documented genetically or historically, the total rises to at least 60 breeds and probably more.
References
American Kennel Club. Breed standards and colour registries for numerous breeds, including the Bulldog and French Bulldog:
Bulldog breed standard (AKC)
French Bulldog breed standard (AKC)
Fédération Cynologique Internationale (FCI). 2026. FCI Breeds Nomenclature and Recognised Colour Varieties.
FCI nomenclature and colour varieties
Schmutz, S.M. & Berryere, T.G. 2007. Genes affecting coat colour and pattern in domestic dogs: a review. Animal Genetics 38: 539–549.
Little, C.C. 1957. The Inheritance of Coat Color in Dogs. Comstock Publishing Associates, Ithaca, New York.
Sponenberg, D.P. & Rothschild, M.F. 2001. Genetics of colour and hair texture. In: Ruvinsky, A. & Sampson, J. (eds.), The Genetics of the Dog. CABI Publishing, Wallingford, pp. 61–85.
If your objective is a rigorous zoological count, I can compile a breed-by-breed table from FCI, AKC, KC and UKC standards and derive an exact contemporary total.
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Chatgpt
MY QUESTION
In how many breeds of Equus caballus has brindle colouration been recorded? Supply full references.
The difficulty with your question is that brindle is not a breed-defining colour in horses. It is an extremely rare phenotype that has appeared sporadically in numerous breeds, often as a result of chimerism, somatic mosaicism, or (in some lineages) the X-linked Brindle1 (BR1) mutation.
Consequently, there is no authoritative census of all horse breeds in which brindling has ever occurred. The best-documented compilations come from Sharon Batteate’s long-running survey of brindle horses and derivative summaries. These sources record brindling in the following breeds or breed groups:
Arabian
Thoroughbred
Mustang
American Quarter Horse
Tennessee Walking Horse
German Warmblood
Bavarian Warmblood
Russian horses (breed unspecified in some reports)
Spanish horses (breed unspecified in some reports)
That yields a minimum of nine breed or breed-group categories explicitly documented in the literature compiled by Batteate.
However, the true number is certainly higher. Individual documented brindle horses are also known from additional breeds, including Warmblood populations not clearly assignable to the “German and Bavarian Warmblood” categories, and the BR1 mutation was characterised in a family of American Quarter Horses.
What can be stated confidently?
At least nine breeds/breed-groups of Equus caballus have published records of brindle coloration.
There is no published comprehensive count of all horse breeds in which brindling has been recorded.
Brindling is regarded as a rare phenotype rather than a recognised colour variety of any horse breed.
References
Batteate, S. Brindle Horses – a Rare Equine Coat Color. Brindle Horses website. Available at: Brindle Horses. Accessed 25 June 2026.
Lusis, J.A. (1942). “Striping Patterns in Domestic Horses.” Genetica 23. (Frequently cited as the earliest scientific treatment of brindling in horses.) Discussed in Batteate’s compilation.
Murgiano, L., Waluk, D.P., et al. (2016). “An Intronic MBTPS2 Variant Results in a Splicing Defect in Horses with Brindle Coat Texture.” G3: Genes, Genomes, Genetics 6: 2349–2358. Summarised in OMIA entry OMIA:002021-9796.
“Brindle.” In: Wikipedia: Brindle (horse section summarising the scientific literature).
If you require only formally recognised breeds (excluding broad categories such as “Russian horses” and “Spanish horses”), the defensible minimum falls to seven named breeds: Arabian, Thoroughbred, Mustang, Quarter Horse, Tennessee Walking Horse, German Warmblood, and Bavarian Warmblood.
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Chatgpt
MY QUESTION
In Felis catus, what is the difference between brindling and the tortoiseshell pattern? Supply full references.
In domestic cats, brindling and the tortoiseshell pattern are not completely separate phenomena. Rather, brindling is one form of tortoiseshell expression.
The confusion arises because the word brindle has a broader zoological meaning (as in dogs or cattle) but a narrower traditional meaning in cat fancy.
Tortoiseshell
A tortoiseshell cat is a cat possessing both orange/red (phaeomelanin) and black-based (eumelanin) pigmentation in an irregular mosaic. This mosaic results from random X-chromosome inactivation in females heterozygous for the Orange locus. The pattern may appear as:
finely intermixed colours,
streaks,
mottling,
or large irregular patches.
Thus, tortoiseshell is fundamentally a genetic colour pattern.
Brindling
In cat terminology, brindled tortoiseshell refers to the form in which the two colours are closely intermixed hair-by-hair or in fine streaks, rather than occurring in large discrete patches.
Classical cat-fancy descriptions explicitly contrast:
brindled tortoiseshells — colours intimately mixed;
patched tortoiseshells — colours occurring in larger blocks or patches.
Consequently, in Felis catus:
Term Meaning
Tortoiseshell Any mosaic of orange/red and black-based pigmentation caused by X-linked colour mosaicism.
Brindling The finely intermixed or streaked form of tortoiseshell coloration.
Comparison with canine brindling
This differs from the classical brindle pattern of dogs, where dark stripes are superimposed on a lighter background through an entirely different genetic mechanism. Canine brindle is a stripe-producing pattern, whereas tortoiseshell brindling in cats is a mosaic of differently pigmented cell lineages produced by X-inactivation.
References
Beaver, B. V. (2003). Feline Behavior: A Guide for Veterinarians. Saunders, St. Louis.
Little, C. C. (1957). The Inheritance of Coat Color in Cats. Comstock Publishing Associates, Ithaca, New York.
Robinson, R. (1991). Genetics for Cat Breeders (4th ed.). Pergamon Press, Oxford.
Lyons, L. A. (2015). “Feline Genetics and Genomics.” In: The Cat: Clinical Medicine and Management. Elsevier, St. Louis.
“Tortoiseshells” in Cat coat genetics.
“Tortoiseshell cat”.
In short, all brindled tortoiseshell cats are tortoiseshells, but not all tortoiseshells are brindled. Brindling is the finely mixed expression of the tortoiseshell mosaic, whereas tortoiseshell is the broader colour pattern itself.
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Chatgpt
MY QUESTION
Is it true that, in any domestic species, mating by a father and mother, both of brindled phenotype, reliably produces brindled offspring? Supply full references.
ANSWER FROM CHATGPT
No. As a general proposition across domestic animals, it is false.
The reason is straightforward: a brindled phenotype does not necessarily correspond to a single homozygous “brindle” genotype. In most domestic species where brindling has been studied genetically, brindled individuals may be heterozygous at one or more loci involved in the expression of the pattern. Consequently, two brindled parents can produce non-brindled offspring.
Dogs (Canis familiaris)
In dogs, brindle is associated with the K locus, where the brindle allele (k^br^) is dominant to k^y^ but recessive to dominant black (K^B^). A brindle dog may therefore be either k^br^k^br^ or k^br^k^y^.
If two brindled dogs are both heterozygous (k^br^k^y^ × k^br^k^y^), Mendelian segregation predicts:
25% k^br^k^br^ (brindle)
50% k^br^k^y^ (brindle)
25% k^y^k^y^ (non-brindle)
Thus two brindled parents do not reliably produce all brindled offspring.
Cattle (Bos taurus)
Brindle inheritance in cattle has long been known to be genetically complex. Classical breeding studies demonstrated segregation of brindle and non-brindle progeny from brindled parents.
Modern work on Korean brindle cattle likewise shows that brindled sires and dams can produce calves that are whole-brindle, part-brindle, brown, or black. In one study of 90 offspring from wholly brindled sires, only 48.3% were wholly brindled, while others were part-brindled, brown, or black.
Another study found that even when both parents were wholly brindled, the proportion of wholly brindled offspring varied substantially according to parental genotypes and was far below 100% in some mating classes.
Horses (Equus caballus)
True hereditary brindling is extraordinarily rare and genetically heterogeneous. Some reported “brindle” phenotypes result from chimerism or developmental mosaicism and are not inherited in a simple Mendelian fashion. Therefore there is certainly no rule that two brindled horses must produce brindled offspring.
Conclusion
I am unaware of any domestic species in which the mere fact that both sire and dam are brindled guarantees brindled offspring. To obtain such a guarantee, one would need a brindle phenotype determined by a fully penetrant homozygous genotype with no alternative segregating alleles affecting expression. The best-studied domestic species—dogs and cattle—do not satisfy that condition. Published breeding data explicitly show non-brindled offspring arising from brindled parents.
References
Berge, S. 1949. “Inheritance of dun, brown and brindle colour in cattle.” Heredity 3:195–204. DOI: 10.1038/hdy.1949.11.
Park, J.-H. et al. 2014. “Sires’ MC1R Genotypes and Coat Color of the Offspring of the Chikso (Korean Brindle Cattle).” Journal of Animal Reproduction and Biotechnology 29(1):21–27.
Lee et al. 2018. “Interaction between E+ and Abr loci is associated with brindle coat color in Korean Hanwoo cattle.” Journal of Animal Science (supplemental abstract).
Kerns, J.A. et al. 2007. “Linkage and segregation analysis of black and brindle coat color in domestic dogs.” Genetics 176:1679–1689. (summarized in the sources above).
Muller, S. 2021. “Brindle color – partial dominance and epistasis.” Biology LibreTexts.