Archive | August, 2011

Tobiano, the “top dog” pattern

BFTovero

When it comes to how the different patterns interact, tobiano could be called the top dog. Pretty much no matter what else it gets paired with, the end result still looks pretty much like a tobiano. Sometimes the other patterns add new areas of white, like this tovero here with the bald face and white ear, but visually it is still pretty easy to identify the horse as carrying tobiano.

Here is an pony with both the appaloosa and tobiano patterns. Notice how the white areas from the tobiano just overlay the leopard pattern.

PintaloosaPony1

The lighting for that picture was just right to show the tobiano markings. In bright light, it would be possible to miss it. The outline is also lost as the pattern travels up his hindquarter, when it meets what would likely be the pink-skinned area on a leopard.

PintaloosaPony2

Here is tobiano overlapping dark-headed frosty roan.

RoanTobi

Tobiano even stays intact when inherited by zebra hybrids. (Photo from Wikipedia Commons.)

800px-Zorse

It is tamped down and made more minimal in donkey crosses, but it is still quite obviously tobiano. (Photo by Amanda Slater.)

800px-Mule_Plough_TeamAmandaSlater

Which brings me back to the discussion about white Miniatures from a few days ago. I truly did not think the colt in question was a Dominant White, but rather a tobiano that was rapidly greying out. As a young foal, he looked like a chestnut tobiano. It did lead to the question, though, about what Dominant White might look like paired with tobiano. Would it overlap the pigmented areas (few though they might be in many cases), much like it did with the leopard above? Or would the instructions to make the horse white override the tobiano patterning altogether?

I suspect that the answer lies in the way the two patterns function at the molecular level. I enjoy reading papers about that aspect of genetics, but in many ways that is above my pay grade. As an artist, I am at heart someone who understands the nuances of phenotype (that is, how the horse looks) far more thoroughly than I understand the underlying mechanics. I will need to wait until someone crosses a Dominant White (particularly one of the families that tends towards the “leaky” variety rather than the all-white) with a tobiano to find out.

Continue Reading

Early greys and fading whites

earlygrey

A short time after the posts about Dominant White went out, I was contacted by someone about a family of seemingly white Miniatures. The stallion was advertised as a maximum white sabino, which is often how Dominant White horses are described. The writer wanted to know if I thought the horse was a White or a Sabino. She thought they might be Whites because of this quote from the Wikipedia entry about the color.

Horses with the W3 allele often retain interspersed flecks or regions of pigmented skin and hair, which may fade with time.

That quote was in reference to the third identified family of Dominant Whites, which began with the mutation in the Arabian stallion R Khasper. A few of the other Dominant White families – but not all – have this same tendency. Photos of the Freiberger horses in the original white study (W1, the Cigale family) show this phenomenon really well.

Here is a Cigale descendant as a foal.

514px-DominantWhiteHorsesB

Here he is as a mature horse.

653px-DominantWhiteHorsesC

(Both photos are from the original journal article by Haas and Brooks.)

The writer wondered if the same thing was happening with the Miniatures. Looking at the pictures, it was clear that whatever else was going on with the stallion, he was a tobiano because he was throwing a lot of tobiano foals from unmarked mares. The fact that some of those tobiano foals turned white really quickly was why Dominant White was suspected. Because the dark areas of their tobiano patterns looked to have uniformly dark skin, my own suspicion was that the foals at least were not White, but early greys.

Andrea Caudill sent the picture at the top of this post, and it is perhaps helpful in this case. The colt is two years old, and almost entirely white grey. His legs are muddy in the photos, but Andrea says they were also white. As a thin-coated race horse in what is probably a wet environment, it’s easy to see his dark skin. In my experience, it can be much harder to tell white greys with extensive markings or facial depigmentation from truly white horses when they are dry and have denser coats.

Some horses, like this colt, do grey really early. Famous white grey breeds like the Lipizzans and Kladrubers have been bred specifically for early and thorough greying. Conversely, breeds like the Percheron have been bred for later greying, so it would appear that greying speed can be manipulated by selective breeding. Perhaps even more interesting, and relevant to the situation with the Miniatures, is that early studies on the silver gene mentioned that pairing silver (Z) with grey (G) produced really rapid greying. I do not believe this was studied in-depth, but it is true that a number of Shetland breeders in the mid-twentieth century were attempting to breed “white” ponies that were in fact early greys. That might be what was happening with the Miniatures in question.

Continue Reading

Artistic liberties

13thcentury3

I am often amused by horse books – often those about colored horses – that point to old art work as proof that this or that color has a long history. Perhaps because I am an artist working in a field where success is often measured by the accuracy with which color can be rendered, I am all too familiar with how this can go wrong. It is a lot easier to be sure that the Pech Merle cave paintings portray appaloosas when you haven’t looked at many artist’s first attempts at painting a dapple grey!

I thought of this again when I was in Germany and came upon these illustrations from a 13th century book of love poetry. Why such pictures were hanging in the Medieval Torture Museum, right along with the comfy chair, I cannot guess!

13thcentury2

I suspect that the artists intended to depict dapple greys with most of these polka-dotted horses. Certainly that seems the most logical explanation for the blue ones at least. Just what the yellow ochre pony with the white dots is supposed to be is open to speculation. Is he a dappled palomino? Some kind of brownish horse turning grey? Or were dapples the crazy all those centuries ago, just as they once were with equine collectibles, so that they were added to just about any body color whenever the horse needed to be made more special? Were there thirteenth century equine art fans bemoaning the fact that the illuminators just couldn’t leave a plain color alone?

13thcentury1

Maybe that could explain the white dots on the very red horse in the background of this illustration, as well as those on the gray (mostly covered with trappings) and the taupe pony.

These pictures illustrate the problem with using art to assess horse color in distant times. Our modern perspective makes it tempting to say that the taupe pony is evidence that silver dapple must have existed in Germany at the time. It is a color we associate with ponies, and he does look small relative to his rider. Unlike the other horse in the same series, he is taupe and not golden brown. Yet he matches the brown on the ground, just as the previous one matches the falcons. It might mean nothing. Likewise the size of the rider relative to the horse might not be intentional, or might be used to indicate something other than the size of his mount. We can only guess.

All artists take liberties, and most are influenced by the conventions adopted by their colleagues. This can skew an entire era of work in such a way that it distorts reality. (When it was still published, The Boat has a wonderful set of articles on painting conventions prevalent in equine collectibles. Excerpts can be seen here, here and here.) A good example of this in historical equine art is the seventeenth and eighteenth century depiction of horse form.

CerberoNeopolitano
Cerbero by Johann Georg von Hamilton, 1725

Artists of that era tend to distort horses in a fairly predictable way. The accuracy and detail with which the color is rendered, however, is striking. (Note the cat tracks and the isolated roan patch on Cerbero, for instance.)

Yet even when horse color is rendered with such precision, it can be hard to know what liberties were taken – or what gaps in knowledge had to be filled in. That brings us back to yesterday’s post on the Royal Creams. Artists frequently painted the Creams. A print of this one hangs in the foyer of my home.

Adonis_JamesWardqrtsize
Adonis by James Ward, 1826

Adonis is usually referred to as a Hanover White, which were bred alongside the Creams in the early days of the Royal Stud. In the painting he has blue-green eyes. Was that accurate? Part of why the nature of the dilution carried by the Creams has remained a mystery is that there are so many conflicting stories about their eye color, so the eye color on a horse like Adonis is particularly interesting. Did the artist know the eye color? The painting was made six years after the death of his owner, King George III, so it is possible that he was only working from descriptions. Maybe the color wasn’t important to anyone, and the artist just liked how the blue picked up the tones in the background.

cream
Beauty, another of King George III’s horses

Is that why this Cream, another stallion owned by King George III, has golden eyes? Certainly the artist took liberties with the size of the eyes, as many artists did at the time. Could he have done the same with the color?

As much as I love historical artwork, and find myself searching it for clues about historical colors, it is not an absolutely reliable witness.

Continue Reading