fuck

fuck

Tuesday, 14 January 2014

Examining a Pleistocene Wild horse's body conformation

The Pleistocene Wild horse skeleton from Denmark displayed at Kopenhagen is perhaps the only complete specimen of Equus ferus from that epoch that is available on the web. I always suspected that it was a member of the przewalskii subspecies that far more widespread during the Würm glacial and also present in Europe, as cave paintings show. However, on sorraia.org there is the claim that this skeleton is practically identical to that of a Sorraia. In the lack of a complete Sorraia skeleton to compare with, we have to take the other way to verify this statement and do an anatomically correct reconstruction of the skeleton and compare both animals in flesh. This is less precise than working with the skeletons, but better than nothing. Note that the skeleton is mounted incorrectly, like most museum mounts (the post of the legs is unnatural, the neck should have an S-curvature). This how the animal should roughly look like in life: 


I chose a bay dun colour because this is seemingly the most common wild type colour of Equus ferus, and there is no genetic evidence for black dun during the glacial yet. I restored it with a standing mane because it seemed advantageous to me in a dry environment. But a falling mane is possible as well, as it is a good protection from heat loss and snow, and mummified Pleistocene horses from Siberia show a falling mane as well. In this case, it probably would be a member of the ferus subspecies. The snout in this reconstruction probably is a bit too long, you see the more precise head reconstruction of the specimen here

After doing the reconstruction, I superimposed three primitive horse breeds over the image to get an idea of which body conformation comes closer to this wild horse. These three breeds I chose are a Przewalski-influenced Heck horse, an Exmoor, and a Sorraia-type Kiger mustang. 


Image sources: 
Heck: http://cdn.fotocommunity.com/Tiere/Tier-und-Mensch/Przewalski-Pferde-a20563865.jpg
Exmoor: http://i68.photobucket.com/albums/i40/VickiE_87/Conformation%20Clinic/Banjo_2.jpg
Kiger Mustang: Wikimedia Commons

The trunk length is the benchmark. The Heck horse and the reconstructed wild horse have almost no proportional differences (if you think the Heck horse has a shorter neck, keep in mind that it has its neck in a more upright position), but the head is slightly shorter. The Exmoor pony has legs shorter by about 7%, but apart from that, the proportions are similar. Again, the snout is shorter. The Kiger Mustang, which's phenotype is identical to that of a Sorraia, has legs longer than those of the wild horse by about 9%. The neck and skull might be slightly longer as well, but this is not measurable because the animal does show them in a lateral position. 
But metric proportions are not the only important aspect of the body conformation. All historic wild horses are described having strong legs, and primitive ponies like the Exmoor and kin or the Konik do so as well. I reconstructed the thickness of the legs with the aid of this superb drawing of a Przewalski's horse: 


As you see, the lim bones of this Przewalski's horse are about as thick/slender as in the fossil horse, therefore I made the legs in my reconstruction as robust. Of the living horses I compared it with, the Heck horse comes closer regarding the thickness of the legs. The Exmoor's are a bit thinner, and those of the Sorraia-type Mustang are way thinner. 

Mind that this comparison is, enforcedly, based on a very small sample - just one skeleton, and pleistocene Equus ferus seemingly were quite variable. Furthermore, horses from that epoch probably are not a prime comparison for what European wild horses would look like if they hadn't been exterminated by man. The increased forestation during the Holocene might have caused a change in body conformation, probably leading to a smaller and stockier type - but as I always say, trustable osteologic data is needed. 
But what I can say based on that comparison is that the skeleton of this Pleistocene wild horse is very likely not identical to that of a Sorraia.  

25 comments:

  1. Daniel, wouldn't it be good to metricaly compare the skeletal dimension of the different bones of the danish horse with the findings of dr Vera Eisenmann ?
    thickness of legs is depending on the dimensions of the skeleton, especially the metacarpus or canonbone (and the 1st phalange). Therefore a comparison of those bones is prominent : danish - przewalski - studies of dr VE....

    ReplyDelete
    Replies
    1. That's a very good idea, I also know photos of the respective bones of an Exmoor. Which study of Eisenmann are you referring to?

      Delete
  2. Nother great post! Keep up the great work.

    ReplyDelete
  3. http://www.vera-eisenmann.com/

    ReplyDelete
    Replies
    1. I find it really difficult to navigate on her homepage and was unable to find a useful paper for my purpose, do you have a direct link perhaps? I didn't find an email address to contact her either.

      Delete
  4. http://www.vera-eisenmann.com/skulls-system-of-measurements
    http://www.vera-eisenmann.com/-cranes-d-e-caballus-

    Daniel, if you take the link "plan dus site" you can find a listing with all your heart and brain need ! :)
    http://www.vera-eisenmann.com/spip.php?page=plan

    ReplyDelete
  5. I have a question for you. Out of all types of conformation would you consider colour the least important? A horse or pony or whatever might be an exact match for a primitive type because of its skeletal structure. It may just differ in colour to what might be desired.

    ReplyDelete
  6. if I may make a remark on the colorsubject : to often color is interpreted as just that, another color, but if you further look into the genetics you will find out that with the changes of color there are linked a lot of other problems, to name some : deafness, nightblindness, other sightproblems, digestive problems.....
    Pigment is filled in from the neural crest, as well as is the nervoussystem, interior organs develop from the same layer as the outer skin. When problems occur on the skin, it is logical you will see other problems too

    ReplyDelete
    Replies
    1. If you could 'Don' provide a few links to support what you are saying. It sounds really interesting and I would like to find out more about it. I know that some spotted ponies suffer night blindness.

      Delete
  7. Homozygous "LpLp"horses, those are appaloosapatterned horses but specifically with white-whitout-spotting (Lp stands for Leopardcomplex or appaloosa-roan)on the body are all nighblind : you can find more on this here : http://www.appaloosaproject.co/articles/free-articles.html
    The foal in my avatar is such a horse as well as his mother running beside him, quite a difference in colorappearance though !
    Pruvost et Al did find the Lp-gene in predomestication samples, which is quite strange since you would think the nightblind condition is nor really a good point for survival.

    The color "chocolate" or "taft" caused by the silver-gene "Z" (dilution of eumelanin) is known for lens-problems in the eye.
    In paint or pintopatterned horses (big patches in a certain pattern called "frame-overo") the homozygousity leads to liveborn foals but with a neurological default in the gut just before the rectum leading to a painfull dead in 24 hours after birth.
    In other whitepatterned colortypes provoking blue eyes (in dogs, cats, mice .... aswell) this goes together with hearingconditions, partial to complete deafness.

    this is a site by a geneticist which is quiet informatif on color in horses with descriptions of specific problems : http://www.horse-genetics.com/horse-color-genetics.html

    Diluted colored horses (Sivler, cream, pearl, champagne) are als known for skin that is more suffering to tear and wear aswell as to sunburn (UV)

    some other links :
    http://en.wikipedia.org/wiki/Hirschsprung%27s_disease
    http://en.wikipedia.org/wiki/Chediak%E2%80%93Higashi_syndrome
    http://en.wikipedia.org/wiki/Waardenburg-Shah_syndrome

    ReplyDelete
    Replies
    1. Thanx for the a above links.
      I live on the edge of Darmoor Devon. The reason I want to know about color is because of the complicated situation of the ponies on Dartmoor. Evidence exists to support the presence of domestic ponies on Dartmoor since the bronze age. But the present pony population is mainly composed of a broad range of introductions mixed with the former population. The result is 3 main types of pony .
      The situation is complicated as all the types have an uncertain future.
      I have been trying to understand all the above but so little scientific work has been carried out. The official Dartmoor pony is considered to resemble the original and ancient breed that I habited the moor. The Exmoor pony and the Dartmoor are very similar and it is likely that the Exmoor was but only an outlying outpost of a South Western type. The Dartmoor has since been outcrossed with arab and hakney, as well as some other influences. The pedigree herds dont run on the moor accept in new takes.

      So their are two main issues. A breed much inbred and reducing in size with most of its members off the moor altogether, and certainly less wild. Then of a wilder and tougher relative in the hill pony already on the moor and surviving, and yet still threatened as there is no real market for foals. A pedigree dartmoor will cost you £500 and a hillpony £80. There are some who beleive the relict population of unregistered heritage ponies should eventually replace the hill ponies role.
      There is thus a lot of disagreement as to which way to best conserve the pony population, or to which of the three types should be promoted. The Dartmoor and Heritage ponies posess primitive colours but represent a smaller group and are thus less diverse. The hillponys do however demonstrate what shape and sise of pony best suits the environment. And the proof of this is how they thrive. The hill ponys are a mixture of all the relict breeds extant in the uk. Its just their colouration, with examples of bay grey dun and rare spotted and silver.
      In terms of Breeding back, do you think that the hill pony population is
      Well placed for a breeding back experiment. There is more genetically diversity within the hill pony population, than ever could be quickly recreated with a captive breeding program. And they represent the exact mixture of breeds mentioned on this blog. And they have already adapted to the local terrain. It seems that the bay gene is growing in number and it makes you wonder just what would happen in time.

      Delete
  8. hi "unknown", I got you allready on FB, so you'll know me by now. I like and completely support your drive to start an eco-packtouring-bizz overthere !
    With respect to the ponies, I think all brittish ponybreeds have been influenced by input of arabian and thoroughbred studs, the same was done in the US with the mustangs, with that difference that mustangs were completely made up out of domestic-horses-gone-feral.
    The Dartmoor-pedigree has become in fact a modernised sportspony, a breed like so many others, while the hillbillies are a mixup in an effort to make them more "commercial" leaning on the modern principle of the "pink-pony" (lovelycolored fluffy petponies), which is to my eyes a really bad thing. What is good, is that they still remain under nearly wildrunning conditions and that they adapted (or kept their adaptation) to the specific environment of the moors.
    I think it would be best to start with the heritage-group and enlarge that group with a selection of the best individuals of the hillponies. A selection on type, temperament, conformation AND color. Color is the easiest if you know a little of how the genes work : select for pangare-bay, wildbay, eventually black and certainly dun (the real dun since in the UK dun is often understood as "cream" (buckskin, palomino....)) - dun in baydun or blackdun (grulla), no red dun ! Purge out all white, the whitepatterns as well as the white stars, blazes, snips, lists, socks, hocks and other.....
    Then you have to decide what type/conformation is wanted in respect to the original equus ferus "subspecies" that was local before domestication (if there was such a group !?). Anyway you should select away from the typical arabian concave head (allthough that type of head can be due to selected paedomorhy or to dwarfism (see Shetlandpony).

    The genetic diversity based on the apearance of all colors is in fact a false diversity, it is diversity in genetic abrasion.

    So you would probably end up with an exmoor type pony, perhaps a little larger (1,30-1,35cm - ap.13 hands), a more straight or even convex profile of the head, a little longer legs (I think the exmoor is allready going the way of the dwarfed shedlandpony) and in the darker colorfazes : from wildbay, over pangarebay, to linebackdun and -grulla....
    (do you have by the way any pics of linebackdun dartmoors ?)
    what do you think ?
    Peter

    ReplyDelete
    Replies
    1. Hi Peter, your breeding proposal is a very good idea, I think the same could be done with the Icelandic horse, it includes bay dun as much as black dun individuals too as you know.

      Delete
    2. well daniel, I'm full of good ideas ! ;)
      but you have to remind in regard to the icelandic "horse" (people do not want to call it a pony, whatever !), that they come all from domestic stock, compared to the brittish ponys of which you can presume a certain "wild" background ( allthough there is discussion about this too).
      The icelandic horse is very diverse in color but since there are since long no imports allowed they all stem from a narrow population. What is important in this, is that all icelandic horses have more than the 3 standard or natural gaits, being walk, trot and canter. Most of them have lateral gaits of which the breedfanciers say those are the natural gaits of 4x4-ponies (offroad-ponies ;) ) But a scientific study detected a responsable genetic mutation for these lateral gaits, that leads, as usual, to one ancestor, which makes the diversity even more narrowed down....
      Furthermore the genetic mutation is a neurological defect in the coordination between left-right movement.

      peter

      Delete
    3. I don't think that British ponies derive from wild horses or experienced more introgression than other European domestic horses,at least there is absolutely no hint for that based on the literature I know. Do you know more about it, perhaps?
      Daniel

      Delete
    4. I thought there were 2 theories :
      1- there were no wild equides on the islands, all horses have been brought there and are derived from domestic stock (Celtic ponies)
      2- there were pockets of wild horses left on the islands, they were there since the last glacial when the ocean between Brittain, France and Iberia had withdrawn....

      Delete
    5. It's pretty solid that wild horses died out in Great Britain at the end of (or was it in?) the mesolithic, and after that there were no equines on Britain until domestic stock was introduced. I don't know of any source claiming otherwise; therefore, british ponies are necessarily domestic stock, and also genetic evidence shows that they are pretty "normal" domestic ponies. Regarding iceland, there never were wild horses because the island was completely covered in ice during the glacial and there was/is no land bridge connecting it to GB or the mainland during the interglacials.

      Delete
    6. I agree with you both. I have a theory that the population in the south west arrived in a domestic state. Its highly likely they were imported to fulfil a specific purpose, tin ore. The Iberian peninsula and sw England both possessed tin deposits that may have been worked by bronze age tin streamers. Both regions are rich in bronze age remains. On Dartmoor most early settlement was along the river valleys, close to the source of tin. Beaker pottery seems to have first developed in Iberia before spreading through trade to other regions, including southern England. Both regions have populations of very similar ponies. There is no tin on Exmoor. But iron was mined by the Romans.
      On Dartmoor there are many hundreds of round pounds used for rounding up livestock. Most date from the bronze age and some continued to be used in the pony drifts until recently. There is also another feature of interest, long low drystone walls known as reaves. Set up in the bronze age to divide up the moor.
      Further still long distance trackways such as the Ickneild way and the ridgeway link up to the sw suggesting tin was exported to many distant regions.
      The problem is that the acidic soils do not preserve bone very well, so its only in the chalk and limestone regions along the ridgeways that bronze age horse bones have been recovered.
      Traditionally the Phonesians introduced the horse to Britain. But what would Phonesian horses have looked like. Probably like an arab.

      Delete
  9. The difficulty on Dartmoor is the different factions supporting the different groups of ponies. Most farmers are likely to abandon the hillponies because of a poor market. But they are resistant of the idea of breeding more traditional types. The hillponies are considered and promoted as tougher and apparently more likely to sell. If money were available I think most farmers and breeders would quite happily breed the heritage type.
    Personally I still have to make my mind up. I feel that both breed and feral type are of equal importance, so any breeding back on Dartmoor would have to utilise the population that is in place.
    There are certainly many bay and pangare mares.
    In regards to dun dartmoors I know of two in a field nearbye. They are not true bloods though but unregisteted. There are a few semi feral duns. I will see if I can get a photo and send it on fb. Sam.

    ReplyDelete
  10. thanks Sam !
    for the moment there is no market for any horse I think. Last years there was way to much breeding, considered and not. Bad economics really made the market collapse, there are more horses for sale than sold, or they are sold for meat at very low prices or simply abandoned (especially in the UK and ireland). I read that the original population of the exmoors is now under pressure because of fly-grazing and abondenment of completely different horses (vanners, tinkers, gypsiehorses....) and common opinion doesn't want them to be removed, slaughtered or euthanised.....
    Peter

    ReplyDelete
  11. Is it really the Mongolian subspecies depicted in west European cave art? The shape of the back and head on those paintings is much more similar to the domestic horse. Could it be a third subspecies?

    ReplyDelete
    Replies
    1. I think that it is indeed the asiatic subspecies, przewalskii (which wasn't restricted to mongolia until recent historical times). I think that many of those cave paintings show an unambiguous przewalski look, also considering that paintings often are not precise enough to judge the exact appearance in all details.

      Delete
  12. I suppose ancient dna will give us an answer one day.

    ReplyDelete
  13. About wild horses:
    http://www.eurowildlife.org/news/revolution-in-science-the-wild-horse-looked-completely-different-genetic-research-has-found/

    http://www.beringia.com/research/horse.html

    ReplyDelete
    Replies
    1. That study says nothing new, actually. What authors of that European Wildlife article do not see is that the study says nothing about the dun locus, and without that information we cannot say whether the horses were in fact bay dun (like the przewalski) or bay. I - and I bet most scientists - am sure that these pleistocene wild horses had the dun colouration. But I didn't expect this article to be objective, since these organizations are promoting the Exmoor pony and trying to diminish the Konik, I don't understand why these organizations cannot effort an objective take-on.

      Delete