Living the Scientific Life (Scientist, Interrupted)

It’s a Zorse, Of Course

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This equid with distinctive markings is a zorse — the hybrid offspring of a female zebra and a male horse.

Eclyse (Ek LEE za) is the latest addition to the German safari park, Schloss Holte Stukenbrock. Eclyse is also special as zorses, or zebroids as they are also known, are typically the product of a horse mare that has bred with a zebra stallion. Her mother, on the other hand, was a zebra.

Image: Reuters [larger]

The creature pictured above is a one-year-old zorse — a hybrid between a female Chapmann’s zebra and a male horse, and what you see in that image are her natural markings. Instead of being striped all over, as most zebra-horse hybrids are, this animal is primarily white with bold striped patches, one on her head and the other on her left hind quarters, making her look like she was sewn together using parts from either a zebra or a horse, a la Frankenstein’s monster.

Additionally, this hybrid is unusual because most zorses are the product of a female horse and a male zebra.

Nevertheless, Eclyse was an accident. Her mother, Eclipse, was visiting a ranch in Italy where she ranged freely with a number of horses and zebras. One horse, Ulysses, spent a lot of time with Eclipse and surprisingly, ended up becoming her father.

Before she returned to her safari park home, Eclipse surprised her keepers by giving birth to a peculiarly-marked horse-zebra foal. The foal, a female, whose very appearance is a testament to her mixed parentage, was given a name that is a combination of her parents’ names, Eclyse (ek LEE za).

Not only do Eclyse’s markings reflect her unusual parentage, but her personality does, also.

“You can tell she is a mix just by looking at her. But in temperament she can also exhibit characteristics from each parent,” observed Udo Richter, spokesman for the park. “She is usually relatively tame like a horse but occasionally shows the fiery temperament of a zebra, leaping around like one.”

Eclyse is a major attraction at the safari park at Schloss Holte Stukenbrock, near the German border with Holland, where she recently arrived from Italy. The safari park has given Eclyse with her own enclosure and plans to provide her with a male horse as a companion.

“She’ll get a boyfriend, as we hope it might be possible to cross-breed again, but also so she doesn’t have to stand here alone,” said park veterinarian, Heiner Vorbohle.

Despite the veterinarian’s hopes, it is highly unlikely that Eclyse would be capable of breeding successfully because she is a hybrid. A horse has 64 chromosomes, whereas a zebra has only 44. Due to the resulting lack of chromosomal pairing, Eclyse is very likely to be sterile, just as other hybrid horses, such as mules, are.

Horses and zebras are often hybridized in Africa for use as pack animals on Mount Kenya.

Sources

ITV News (quotes)

ABC News.

Courier-Mail.

Comments

  1. #1 Jamie
    July 5, 2007

    Hey Grrl!

    I just wanted to give a bit of input on the Zorse filly… 🙂 One of my good friends is the registrar for the American Donkey and Mule Society (ADMS), which also governs Zebra and Hybrid registrations for the US. She told me that it is terribly uncommon for Zorse juveniles that are the product of a cross between a Zebra mare and a Stallion do not typically make it to maturity, but that crosses of a Zebra Stallion on a Mare usually do well. Nobody’s really sure why that is, but it also hasn’t been explored that extensively.

    Just thought you might like a bit of trivia today!
    Jamie

  2. #2 Bob
    July 5, 2007

    Instead of being striped all over, as most zebra-horse hybrids are, this animal is primarily white with bold striped patches, one on her head and the other on her left hind quarters, making her look like she was sewn together using parts from either a zebra or a horse, a la Frankenstein’s monster.

    No, she looks like a hybrid of a zebra and some whitewash, which she probably is. Bet they don’t have any pics of her when it’s raining.

  3. #3 llewelly
    July 5, 2007

    If you google images for pics of ‘zorse’ you’ll see that none of them (except the ones in your post) have such clean contrasting demarcations between horse-like coloration and zebra-like coloration. Although horse zebra hybrids are real, I suspect these pics are horse-photoshop or zebra-whitewash hybrids.

  4. #4 "GrrlScientist"
    July 5, 2007

    i am inclined to believe she is real because her patches are brown with blackish stripes, as typical zorses show, instead of white with black stripes. also, look at that patch on her hindquarters; the stripes aren’t perfect, especially near the top of that patch. further, her nose is dark brown instead of black, as is a typical zebra’s nose is. also, she has a horse tail, instead of a zebra tail.

  5. #5 Oran_Taran
    July 5, 2007

    Interesting… how exactly does the whole chromosome thing work? does there have to be a genetic fluke in order for the hybridization to work, or does mating any two horse/zebra pairs result in offspring?

    The coloration reminds me of gynandromorphs (which of course this is NOT an example of) and x-chromosome mosaics (is that what you call it? I forgot). Since this one is unusual because it’s mom was the zebra one and because of it’s coloration, could it be that some gene influencing stripes is an x-linked trait?

  6. #6 Melissa
    July 6, 2007

    If you google images for pics of ‘zorse’ you’ll see that none of them (except the ones in your post) have such clean contrasting demarcations between horse-like coloration and zebra-like coloration. Although horse zebra hybrids are real, I suspect these pics are horse-photoshop or zebra-whitewash hybrids.

    That is true that most look like the ones found on Google images, but most crossbreds are produced from solid color horses. Crossing a piebald with a zebra is unusual if not unique.

  7. #7 Torbjörn Larsson, OM
    July 6, 2007

    A spontaneous crossing – talk about product out-zorse. 😛

    she looks like a hybrid of a zebra and some whitewash

    Females are mosaics, because in x-inactivation ( http://en.wikipedia.org/wiki/X-inactivation ) either x-chromosome can be chosen to be active in the . So perhaps the coloration are tied into that, as discussed above. Calico cats is the classical example of such coloration from x-inactivation.

    IIRC zebra coloring is dominant (which would explain why one seldom sees variants). And I’m not sure about horse colorations, but the local press claimed that white color is dominant. Which factoids would support an x-inactivation scenario.

  8. #8 Torbjörn Larsson, OM
    July 6, 2007

    “either x-chromosome can be chosen to be active in the” – either x-chromosome can be chosen to be active in placentals.

  9. #9 llewelly
    July 6, 2007

    Thank you, GS, for your comments about the brown background of the zorse’s stripes (which rules out whitewash but not photoshop), and thanks to Torbjorn for reminding me of x-inactivation, which helps explain the clean separations between horse-like and zebra-like coloration.

  10. #10 Henk Poley
    July 6, 2007

    In humans, such (rare) clear cut differences in skin / hair colouring are often a case of chimerism. In a chimera part of the cells have a different set of chromosomes. Either by two separate fertilised eggs who stuck together, or by a (rare for mammals) ‘immaculate conception’ and a normally fertilised egg. In the latter case the normal tissue patches up the parts that don’t develop from the cells that have two identical halves of the chromosome set.

    Have they tested for chimerism?

    (Though the grey hair in between the black stripes is an indication that this is a crossbred. But there are zebras that are born black and get whiter when they grow up.)

  11. #11 Bob
    July 6, 2007

    i am inclined to believe she is real because her patches are brown with blackish stripes, as typical zorses show, instead of white with black stripes. also, look at that patch on her hindquarters; the stripes aren’t perfect, especially near the top of that patch. further, her nose is dark brown instead of black, as is a typical zebra’s nose is. also, she has a horse tail, instead of a zebra tail.

    OK, so she’s a whitewashed zorse. That’s my theory and I’m sticking with it!

    The X-inactivation idea is intriguing, though…it would be interesting to know if coloration is really X-linked.

  12. #12 Beth
    July 6, 2007

    I didn’t believe this was real at first. I never heard of a zorse before. I really enjoy reading your blog. By the way, you’ve been tagged. http://easyecoliving.blogspot.com/2007/07/eight-random-facts-meme.html

  13. #13 Oran_Taran
    July 6, 2007

    Ah, yeah. x-inactivation- That’s what I meant.

    The problem I see with that hypothesis is that it has big patches. Shouldn’t the patches be smaller and randomly spread all over the body, like calico cats?

    I didn’t see anything about the size of the patches in my quick scan of the wiki article.

    >Have they tested for chimerism?

    That’s also interesting, but if it were a chimera, the white parts would have to be genetically 100% horse and the striped parts would be 100% zebra, and would require both a horse and a zebra embryo.

    I guess there would be other ways for it to be a chimera, but the likelihood of those other ways happening is WAY too small. Chimeras are very rare as it is.

  14. #14 Bob O'H
    July 6, 2007

    That must be so embarrassing. You’re sat there, painting a nice new zebra, you just reach over for the grey paint, and the damn thing escapes.

    Bob

  15. #15 daedalus2u
    July 6, 2007

    Another option is that there was a somatic mutation during early embryo growth, such as loss of coloration. The regions that are white, look very white, albino even. Different number of chromosomes might make for more instability making such loss more likely.

  16. #16 fireweaver
    July 9, 2007

    actually, the way i understand it is that Ulysses (this zorse’s sire) is a paint horse. if you imagine away the stripes, our little friend is a quite normally-splotched paint horse herself (with a funny zebra-style tail & nose). in paint horses, there are areas of pigmented skin/hair, and areas of non-pigmented skin/hair, so in this particular zorse, only the areas that are pigmented are able to express the otherwise dominant zebra striping pattern. it’s more a phenomenon where the whiteness is epistatic to the stripeyness. it’s not really a case of x-inactivation, as there are plenty of (normal, fertile) male paint horses, and as some of you have pointed out, it lacks the standard mosaic pattern typical of x-inactivation.

  17. #17 Monado
    August 29, 2007

    You certainly see this kind of colouring in cat breeds. I realize they’re not different species but the colour-and-white is because of a gene turning off the colour. You can have black & white, orange-and-white, or tabby-and-white by the same mechanism. And I’ve met lynx-point cats, which are like Siamese in that the cooler areas of the body are darker, but they have pale tabby markings where a Siamese has just colour.

    I’ve seen quite a few pictures of zorses and also the efforts to reconstruct the quagga from the southernmost species of zebra. Eclyse’s colours seem familiar, especially the browning of the zebra pattern.

    The mane also seems hybrid, standing upright for a few inches and then flopping over, like that of an Icelandic horse.

    Just for fun, this link has an image of an Apaloosa saddle mule!

  18. #18 Anne-Marie
    November 26, 2008

    She’s a clear case of X-inactivation. She has the x chromosome of both a horse and a Zebra. Because she has two x chromosomes, only one x chromosome in each of her cells is active, “switched on” if you like. which one that is, is completely random, hence the random colouring. In the stripy patches her mother’s chromosome is active, in the white patches her father’s chromosome is active. That is also the reason why there are usually onle female tabby cats and rarely if ever male tabby cats.

  19. #19 Tori
    December 31, 2008

    She’s definitely real, and I’m pretty sure that the cause of her unique coloring is not a result of anything as exotic as chimerism or x-inactivation or anything. It is just the effect of the “pinto gene”.

    This zorse’s horse parent was a grulla pinto. Grulla is the term for the greyish brown coloration of her base coat. Here is a grulla pinto horse. http://image6.equinenow.com/equine/data/photos/47039_1.jpg

    The thing about pinto horses is that they are NOT white horses with colored patches. They are colored horses with white patches. Their base coat is “covered up” by their white markings. In the case of this zorse, that includes her stripes. Therefore the stripes are only present on the pigmented areas.

    All in all, a very cool animal!

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