A HORSE OF THAT COLOUR

Our forefathers believed firmly that certain qualities and defects in horses were associated with their colour and markings, on the basis of observations as profound as they were inconsistent.

            – Juan Llamas, This is The Spanish Horse

What has colour to do with temperament or performance? And why do so many people have strong prejudices against horses f a certain colour and/or markings? Our perceptions about horses are inevitably affected by the beliefs we hear expressed in equestrian circles. If we are to approach the training and development of horses rationally, we must weigh the evidence and decide which of those beliefs really matter.

       Such ideas as those outlined by Colonel Llamas in the epigraph to this article, while not so strongly held as they were a couple of generations ago, may still be found throughout the horse world. So among top class equestrian competitors we learn that X will never have a black horse, while Y will only have bays; Z will have a chestnut, but only if it has no more than two white feet, and so on and so forth; while breeders will often express regret that instead of the desired bay or grey, their carefully planned mating has thrown up a despised chestnut, etc.

       All kinds of reasons are given for these prejudices, some of them obscure in the extreme to anyone not well versed in the ‘folk wisdom’ of the horse world. Some of these, particularly among breeders, represent theories which may be very deeply entrenched, but which have no foundation in fact. Thus, as Margo Weise points out, ‘A common breeding theory holds the belief that if a horse was prepotent enough to pass on his or her color, then the horse’s other attributes, such as speed and class, would be passed on to the next generation as well.’^[1]

However, the transmission of colour from one generation to another has nothing to do with prepotency and no link has ever been convincingly made between colour and performance. So why do such beliefs and prejudices persist?

       Although colour-prejudices and preferences have existed more or less wherever horses have been ridden or driven, they are not consistent world-wide. For instance, in some cultures greys have been highly regarded, in others despised and shunned. Parti-coloured horses, especially piebalds, were prized by the Mongols (probably because of the disruptive effect of their colouring); the Native Americans, too, have tended to prefer horses with spots or splashes of colour interspersed with white, probably for similar reasons to those of the Mongols. The bedawin tribes of the Arabian Peninsula are often reported as preferring bays, but fashions changed in the desert. The Arabs have variously held bays, blacks, chestnuts and greys (when the latter have turned white) in high esteem. Lady Anne Blunt observed, during her visit to Central Arabia in 1879, that as a rule colour was not much regarded there, since the strain (or pedigee) was all that mattered.

       In Europe, and among European settlers in the Americas, certain beliefs regarding coat colour have proved remarkably consistent and resilient over the centuries, giving rise to the idea that there must be something in such beliefs for them to have persisted for so long. It is a human characteristic to like things tidy and easily labelled so we know what they are, so people have always tried to find ways to label other people and put them in ‘pigeon-holes’. This system of classification makes them believe they know who they are dealing with, and how that other person is likely to react in various situations. (Humans also do this with horses, for the same reason.) This process of ‘pigeonholing’ has been going on for thousands of years, and in the Europe one of the most effective ‘pigeonholers’ was the Greek physician, writer and philosopher Galen (ad 129-c. ad 216). Galen, basing his ideas on those of earlier Greek philosophers, believed that human health depended on the harmony and balance of the four bodily ‘humours’ or fluids: blood, phlegm, choler and bile. He taught that each of the humours was composed of the four elements of which the classical Greeks believed the universe was composed: fire, air, earth and water; and this teaching became enmeshed with earlier Greek concepts, which sought to explain personality traits in terms of their association with the bodily humours. So blood, being associated with enthusiasm, became linked to the air; phlegm, denoting apathy or sluggishness, was linked to water; choler or yellow bile, signifying anger, was linked with fire, and black bile, associated with melancholy, was considered to be of the earth.

       Such concepts exerted a powerful influence on European thinking right up to the seventeenth century, and were eventually assimilated into the great body of what we may call ‘folk wisdom’. It was not until the inaccuracy of many of Galen’s physiological observations  was discovered in the seventeenth century that the doctrine of the ‘four humours’ was finally relinquished. However it retained its hold on ‘folk wisdom’, and it has tended to resurface, often heavily disguised, to this day.

For the Renaissance equestrians on whose teachings the first great revival of Classical horsemanship was based, and in particular for those sixteenth and seventeenth century writers on matters equestrian such as Thomas Blundeville, the ‘received wisdom’ of their day regarding equine coat colours and markings was not merely prejudice or superstition, it was scientific fact. So Blundeville says that a horse

is coloured according as he is complexioned…and he is complexioned according as he doth participate more or less of any of the four elements. If the earth predominates, he is melancholy, heavy and faint-hearted and his colour is black, russet, or a bright or dark dun. If he has more of the water, he is phlegmatic, slow, dull, apt to lose flesh, and his colour is usually milk white. If of the air, he is sanguine, pleasant, nimble and of the bay colour. If of the fire, he is choleric, therefore light, hot and fiery, a stirer, seldom of great strength, and a bright sorrel colour.^[2]

       In Spain we find Pedro de Aguilar in the sixteenth century expressing much the same beliefs as Blundeville. However by the eighteenth century, the ‘Age of Reason’, a number of knowledgeable equestrians had started to question, and in many cases to abandon, the received wisdom regarding coat colours. By the late nineteenth century all manner of horsemen, especially the military, were expressing the view that there are ‘bad horses but no bad colours’. The great Captain Horace Hayes, still widely regarded as an authority in equestrian circles, maintained that ‘From a working point of view, the colour of a horse’s coat, as a rule, does not seem to be of much importance’, although Captain Hayes adds conscientiously that ‘we cannot help being favourably impressed with those of rich and decided shades.’^[3]

       So do the old prejudices regarding colour have any substance to them? Some modern writers seem to feel that they do. For example, Dr Edward Skorkowski of the Kraków Institute of Zootechnics in Poland produced several papers in which he attempted to show a relation between fertility and colour in Polish broodmares, or between success on the racetrack and colour. However Skorkowski’s findings take no account of the many other factors which could be involved, and the apparent correlations he produced are not really of much value. The late Dr Moyra Williams, a respected psychologist who carried out a great deal of work on equine psychology,  considered the possibility, although the qualities she attributes to different coat colours differ in some respects from those traditionally ascribed to them. For instance, she states that

Black horses have the reputation for being touchy and tending to rear. Chestnuts, like red-headed people, are said to be hot-tempered and are apt to pull. Greys are traditionally docile, tame and dependable, while bays have the reputation of being self-willed and mulish.^[4]

       Dr Williams hypothesised that these temperamental differences could be accounted for by the varying distribution of sensory-nerve endings which might occur with different coat colours:

The docile, insensitive grey, for instance, might not only lack pigmentation in its skin, but might also be deficient in touch spots there. it might literally not feel pricks and buffets as acutely as darker coloured individuals, except on its darker muzzle.^[5]

 Elsewhere, Dr Williams enlarged on this theme:

In albinos there is no doubt that sensory deficiencies in the eyes coincide with a lack of pigmentation in the skin; so that the lack of pigmentation in greys as a whole may well be accompanied by a sparsity of sensory nerves in the skin, making them frequently docile and easy to handle.^[6]

       This is an ingenious theory, but there are several things wrong with it. First, there are different types of albinism, not all of which result in extreme depigmentation of skin, hair, and eyes, although all types affect the eyes to a greater or lesser extent. It is an over-simplification to say that eye problems associated with albinism are the result of sensory deficiencies. The retina does not develop normally in albinism, and this affects the nerve pathways from the retina to the brain. This can result in various vision problems as well as an increased sensitivity to light.^[7]

        Second, greying in horses is not related to albinism. It is rather surprising that a horsewoman of Dr Williams’s experience was apparently unaware that except under original white markings (where, as with all horses, the skin is pink) greys do not lack pigmentation in the skin. On the contrary, greys have black skin, as do most other horses. Furthermore, it has never been demonstrated that the sensory nerves in the skin of grey horses differ in any way from those of horses of any other colour.

        Finally, grey horses can be born almost any colour (not just black, as many writers claim). In fact, when one thinks about it, grey is not a colour at all. Indeed, until comparatively recently, grey was considered by some horsemen (including the great racehorse trainer Federico Tesio) to be a disease, possibly because it seemed  to indicate ageing (like the onset of grey hair in humans), but perhaps also because of the true fact that greys are more likely to develop the skin tumours known as melanomas (which are largely benign but which can sometimes be malignant). Grey is actually the result of a process by which, as the horse grows older, pigment is prevented from reaching the hair, so the horse turns progressively grey, and eventually (in most cases) white.

       Whether or not a horse turns grey depends, of course, on his genetic make-up, or genotype (more often referred to as the genome), which in turn determines his physical appearance, or phenotype. This is no simple matter of one gene, one characteristic; most genes have multiple effects, and most characteristics are the result of the action of a number of genes, which interact in ways we are only just beginning to understand.

       To make things even more complicated, most genes also have alternative states, called alleles. Horses, like all other sexually reproducing species, receive one set of genes from their sire, and another set from their dam, so each horse has two alleles of the same gene to pass on to its own offspring. These alleles may be the same, or they may be different. People often talk of one gene being dominant over another, or about genes being recessive (i.e. they may skip one or more generations), but this is incorrect. It is the alleles which are dominant or recessive. So for the dominant allele of the gene which turns a horse grey (usually designated G), the alternative state, or allele, is ‘not grey’ (set out in lower case as g).  As G is dominant, if it is present it will always be expressed. The greying gene itself is not dominant; instead it masks any other colour present. A horse which inherits G will turn grey. If it inherits G from both its parents, then all its offspring will turn grey, because it has no ‘not grey’ allele to pass on. If it inherits one G and one g, then its offspring may or may not turn grey, depending on which allele it passes on to individuals. If neither of its parents is grey, a horse cannot inherit G, because if either of its parents had G to pass on, they in turn would have been grey. So grey cannot skip a generation. Grey horses could therefore be bred out of a horse population quite easily by breeders simply not breeding from greys.

       The coat pigment is produced by substances called melanins. Eumelanin produces black, whereas phaeomelanin produces yellowish-red. The alleles which determine whether a horse is black or chestnut are referred to as alleles of extension, because they extend the pigmentation either to the eumelanin end, producing black, or to phaeomelanin, producing chestnut. The black allele is designated E, because it is dominant over chestnut, or e. If E is inherited, a horse cannot be chestnut; it will be black or bay (bay is produced by the action of another gene, which restricts the black colour to the points, i.e. the mane, tail, legs, tips of ears etc. This gene is known as agouti, after a small South American mammal). If a horse has two E alleles, all its offspring will be black or bay; if it has one E and one e, then its offspring may or may not be black or bay. A chestnut will only result if both parents pass on e; so the easiest way to breed chestnuts is to mate only chestnuts to chestnuts. Since chestnuts have only ee, they cannot produce a black or bay foal, as they don’t have the required alleles of extension to produce eumelanin.

       These are only some of the most common genes which affect coat colour; there are many others, interacting to produce the wonderful variety of coat colours and patterns which can be found in different breeds of horse throughout the world. These interactions are complex and far from fully understood. One set of genes which have posed problems for geneticists and breeders alike are those responsible for the dilution of normal coat colours, producing, for instance, palomino, buckskin, cremello and perlino.

       These dilute colours, together with the question of so-called albinism in horses, have prompted a great deal of speculation, much of it based on inaccurate data. The rare true white (as opposed to the white produced by greying) is not a form of albinism. True albinism has not been fully confirmed in horses, although some tests suggest that there is a similar cause for the light pigmentation found in cremellos^[8], which have ivory hair, pink skin, and, generally, blue eyes (although they may also have amber or hazel eyes).

       Cremellos have traditionally been regarded as ‘soft’ (as have the very similar perlinos). In addition their eyes are often considered weak because of their lightness. Philip Sponenberg disputes this, maintaining that most light-coloured horses see perfectly well and are at no disadvantage compared to dark-eyed horses.^[9] However there is some evidence that blue-eyed horses are more sensitive to the sun, and that they actively seek shade in summer.^[10] Research also shows that pink-skinned horses are more subject to certain carcinomas^[11], but how common this is I have been unable to determine.

       In any case, these are purely physical traits, and do not in themselves give clues as to temperament or ability. The only cremello I have ever ridden was a riding school pony who went like a bomb across country, and was such a safe and accurate jumper that everyone wanted to ride him. Apart from a tendency (shared by many riding school horses) to nip across corners in the school, and a reluctance to canter on the right lead, he was a paragon of riding school virtue and, as far as I could tell, as tough as old boots!

       Although there may be a link between certain of the dilution genes in horses and albinism in other species, there is one important difference: true albinism is a recessive trait (i.e. for it to be expressed, both parents must pass it on), whereas the allele for true white in horses is dominant, and the alleles for colour dilution (such as those which produce cremello, perlino, etc.) show what is called incomplete dominance.

       Since the 1940s various studies have been carried out regarding the relation between coat colour and behaviour.^[12]  Most of these have involved small rodents, mink and foxes, mainly in laboratory conditions; however dingoes, goats, feral cats, roe deer and reindeer have also been observed to see if any correlation between coat colour and behaviour exists.

       In fact, some such correlations have been found. The results vary depending on the species, e.g. the black animals of one species might not show similar behavioural traits to the black animals of another species, even though their behaviour varied from that of others of their own species with different colouring. However, one set of findings did seem fairly consistent. Albinos in general do seem to differ in behaviour from those which retain the ‘wild’ colouring, and are often tamer and more tractable (as opposed to this, a friend of mine who for many years bred rabbits and cavies, and made detailed observation of their behaviour, reports that the albinos – of which she had a number – in no way differed from the others in terms of behaviour).

       The reasons for these variations in behaviour may be found in the chemistry of coat pigmentation. Chemical substances found in the nervous system of animals, called neurotransmitters, play a vital role in processing information. Among these neurotransmitters are substances called catecholamines. These are especially important, as they include dopamine and adrenaline. Dopamine secretion leads to heightened reactions and an intensification in activity, while adrenaline is well-known for the role it plays in the so-called ‘flight-or-fight’ syndrome, where an animal prepares either to flee or to stand and fight.

       Now the melanins, which as we have seen are the coat-colouring pigments, are initially  produced by the same biochemical process as the catecholamines, from the amino acids phenylalanine and tyrosine. The latter are synthesised to produce a substance called dopa, at which point the chemical pathways of the melanins, and the substances which go on to become the catecholamines, diverge. This common origin of the melanins with the catecholamines may account for the way in which animals with certain coat colours appear more reactive than others.      

       However, it is important to understand that we are talking about a very limited set of behaviours here. The differences in behaviour observed in the animals studied represent mainly increases and decreases in reaction to various stimuli, or increases and decreases in general activity. But all this gives us absolutely no indication of the performance potential of horses of specific colours, nor can it explain more than a tiny part of their psychological make-up.

       The sheer complexity of  coat colour genetics makes any attempt to assign specific psychological characteristics to specific coat colours seem like nothing more than an exercise in futility. Nevertheless, one will always find people who are determined to make the effort. To such people I would pose a question. Take those breeds in which all colours except one are either forbidden, or rarely occur. There is, for example, the chestnut of Haflingers and Suffolk Punches; the bay of the Cleveland Bay; the black of the Friesian; and the famous grey of the Lippizaner. Does anyone seriously think that within those breeds one may not find a huge range of variation in temperament, personality and ability? One has only to read Colonel Alois Podhajsky’s moving tribute to the horses in his life, My Horse, My Teachers^[13] to realise that the grey Lipizzaners of the Spanish Riding School (of which Podhajsky was Director for twenty-six years) exhibit just about every kind of equine personality one could imagine! How does one square this with the characteristics traditionally associated with greys?

       Certainly, plenty of horses can be found who fit the stereotypes, just as one may find any number of humans who fit the stereotypes about sex, race, class etc. This is no more than one should expect to find in any large, varying population.

       Among the eight horses currently inhabiting our own stables, the steadiest and most generally reliable is a chestnut with three white feet. The next steadiest and most reliable is that horror of horrors, an Arabian chestnut with four white feet. The flightiest is a bay mare, while the two most sensitive are the grey Arabian stallion and his grey dam.

       One of the scattiest horses I know is a chestnut Arabian mare with three white feet, while the quietest and most dependable horse I know is also an Arabian mare with three white feet!

       I think the last word should rest with that eminently sane and practical master, the great François Robichon de la Guérinière:

Persons interested in coats attribute to horses with these markings an infinite variety of qualities, but the authors who have written so amply on the conclusions to be drawn from markings and the various coats have the weight of experience against them, for the latter proves that the quality of  a horse depends upon its strength and its vigour, which are interior qualities and not qualities of coat or exterior marking. There is but one thing to say in this matter; which is that, for the eye, certain coats are more pleasing than others.’^[14]

©Lesley Skipper

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