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Saturday, 28 December 2013

The Sorraia - is it a wild/ancient horse?


The Sorraia is one of those horse breeds of which some of its advocates claim it is a remnant of a special wild horse population. According to them, the Sorraia descends from supposedly wild horses spotted in the 1920s in a rural region in Portugal, is phenotypically identical with a local wild horse type and genetically similar to the Polish Konik and the Przewalski, endorsing its status as a wild horse. With this post I try to give an overview over which arguments supporting a special status for the Sorraia among other Iberian horse breeds are verifiable, and what seems to be a colourful or wishful interpretation based on my research for this post.
I want to note that all this is my personal interpretation of data that was available for me, if anyone has additional material or disagrees with my reasoning for good reasons, I would like to read about it.

Breed history

First of all, the Sorraia does not descend from any members of that one free-ranging horse herd spotted by Ruy d’Andrade as he was unable to find them again. The Sorraia actually descends from farm horses he thought to resemble those horses which he collected for a breeding program in 1937. All Sorraia descend from four stallions and seven mares of local farm horses, to which a Criollo stallion was added later on.
There are no reports of a feral horse population resembling those spotted by d’Andrade, not even in C. H. Smith’s extremely comprehensive work The Natural History of Horses with Memoir of Gesner. D’Andrade is the only person who saw them, and he saw them only once. I think it is much more likely that he saw just a herd of escaped local farm horses, rather than a population of free-ranging horses that remained undetected for decades or centuries, were spotted by one man and disappeared into the void again. The only references claiming there was an existence of these free-roaming horses prior to d’Andrade’s encounter that I know of is either d’Andrade himself or Hardy Oelke (who is one of the main contemporary Sorraia advocates), so I don’t know of a neutral reference. Sorraia fanciers also claim that the so-called “zebro” (“encebro” in Spain) was a wild Sorraia-type horse that disappeared in historic times. The Zebro was in fact more likely an Iberian wild ass, a late-surviving strain of E. hydruntinus [1] or maybe a population of feral donkeys (their wild nature is no argument against that, as feral animals do in fact re-develop such wild traits). The European wild ass survived the longest on the Iberian Peninsular, the last of these Zebros survived into the 16th century in a game reserve in Murcia [1].
As you see, the modern Sorraia is not older than 80 years, and neither does descend from a wild or feral horse population but from local farm horses (just like the Konik, by the way). Nevertheless, there is still the possibility that these farm horses may have been genetically influenced by surrounding wild horses, so let’s have a look at what genetic studies say about this horse breed so far.

Genetics

There is some debate on whether the Sorraia is the ancestor of other, similar Iberian-based horse breeds like the Lusitano or various Mustang lineages. This is in fact not really relevant for the question stated in the headline of this post; domestic breeds do give rise to other breeds, that does not place them closer to their wild type. But since the population that is called Sorraia originated when d’Andrade started his breeding programme in 1937, it is chronologically not possible that the modern Sorraia gave rise to similar Mustangs and the Lusitano, though I think its possible that they derive from a common stock, as genetic similarities between the Sorraia and the Lusitano[2,3,4] and phenotypic match with some Mustangs (f.e. Kiger) suggest. It is not relevant for the wild horse debate anyway.
If the Sorraia is a true wild horse, or at least strongly wild horse-influenced as advocates claim, there should be a clear genetic indication for it. A connection with the Konik, Mongolian and Przewalski horse was suggested in Jansen et al. 2002, but later studies found the Sorraia to be more or less closely related to other Iberian horses [3,4,5,6].  Luis et al. 2007 write: “Because of its low variability, the Sorraia usually separated from the other [Iberian] breeds when only one type of marker was used, seen also in […]. However, when we used all three types of markers the Sorraia clustered with the other Iberian and Iberian influenced-breeds […] However, new results from mtDNA analysis revealed a lost haplotype in the Sorraia breed, which is included in the mtDNA haplogroup recognized for heaving high frequency in Iberian horses, and the result obtained here indicate closeness of the Sorraia with the other Iberian breeds, which fits historical documentation.”[3] Lira et al. 2009 [5] compared mitochondrial haplotypes of Iberian horses with those of ancient domestic and wild horses from the Neolithic to the Bronze age and Middle age. They find no relationship between the Sorraia and the ancient samples and conclude: “Lastly, our data do not support the Sorraia horses as a primitive predomestic lineage, in contrast to a previous claim (d’Andrade 1945).” The only similarity of the Sorraia with an ancient sample is with one that is from the middle ages, what does not implicate the Sorraia is an ancient, isolated breed. They consider the introgression of local wild mares for all Iberian horses is possible, without giving the Sorraia a special status.
Sorraia advocates argue that the wild horse samples are too small and the genetic diversity in Sorraia too limited to give an accurate clue about its relation to predomestic horses. However, if the Sorraia is truly a remnant of the wildtype of Equus ferus ferus, then it there should be at least some genetic markers totally unique to the Sorraia – unless domestic introgression and genetic bottlenecks purged them out (if that’s the case, it is the question if it still can be considered a representative of the wildtype then). Advocates of the breed argue that absence of evidence is not evidence of absence, and that is true. But it is no good basis for assuming presence either.

Phenotype

Pleistocene horses portrayed in southern European cave paintings are used as a comparison for the Sorraia, and the fact that these painted horses show leg and shoulder stripes is used as an argument to support the primitive nature of the Sorraia. But first of all, keep in mind that the end of the glacial brought a dramatic shift in the range of the Eurasian mammal fauna and terrestrial biomes, and the Pleistocene horse types probably represented a type different from that inhabiting Holocene Iberia. In my personal opinion, it is likely that some of these paintings might represent members of the przewalskii subspecies with standing manes rather than ferus with falling manes. But if we are willing to use these paintings as a reference, what do they tell us? That wild horses had striped legs and shoulders to a certain degree, what is typical of many dun horses and therefore no argument in favour of any breed.
The Sorraia is considered a primitive horse particularly because of its coat colour. It is predominantly grulla-coloured, and grulla is often considered the standard colour of western wild horses (although genetic data suggests that a large portion was coloured bay/bay dun [8,9] and grulla is only one of the colours mentioned for historic wild horses). Black dun has many different shadings, varying from light grayish, dark gray to yellowish to almost optically brown. Some Sorraia apparently also show a bay dun colour (see below). Bay dun and black dun are wildtype colours, and any domestic mutations present in the breed could be explained by domestic influence if we assume the Sorraia is a wild or ancient horse, so the coat colour does not contract this hypothesis. I have to note two things though: 1. the striping of the Sorraia isn’t as exceptional as often stated, stripes are part of wildtype colour + dun expressions and shown by other grulla horses, like the Konik or Hucule (considering that the stripes were regarded as a trademark of the breed right from the beginning, it is also possible that the breeders selected for prominent striping). The there are no photos supporting the claim that the stripes in Sorraia were more prominent in the past. 2. prominent stripes are not the unmistakeable indication of European wild horses as one might think because of the seductively strong striping of the African ass and, obviously, zebras. In fact, historic references for wild or free-ranging horses don’t mention them that often, while the dorsal stripe is nearly always remarked. Also in the Przewalski’s horse the stripes are not that prominent (anymore?).

Striped black dun Hucul, there are even more strongly striped Hucul
This Sorraia seems to be bay dun ©Lynne Gerard

The optic similarity with the Konik, a primitive horse breed from eastern Europe and thus far removed from the Sorraia, provokes the assumption that their phenotypic traits are inherited from a common ancestor since genetic exchange seems very unlikely. But in fact this similarity is grounded almost exclusively on the coat colour features (as primitive Koniks are smaller and more sturdy in build), which are regulated by only two loci (Agouti and Dun) since both breeds are non-sorrel horses. Bicoloured manes and tails, dorsal and leg stripes are part of the expression of black dun (=grulla). Black dun colours are not rare in rural horses and ponies, and it is one of the wildtype colours of Equus ferus; thus its presence in two compared horse breeds is not a surprise and also no indication of a common, predomestic ancestry.
While the coat colour is no argument against a status of the Sorraia as an ancient horse, their body conformation seems problematic. The Sorraia is a quite large (140-150 cm), lightly built horse with a proportionally small and slender head. Historic references for central and eastern European, Russian and even western European wild horses describe a horse type with a body conformation that is quite the opposite – small, stocky, with strong legs and a proportionally large and robust head. However, Sorraia fanciers argue that the Sorraia is a remnant of a specialized Iberian subtype of the wild horse, and there are no historic references describing wild horses from the western Iberian peninsular as far as I know, so that this is not necessarily contradicted. Genetic data suggests that the extinct wild horse population was separated into two main populations: one huge, panmictic population eastern to the Pyrenees inhabiting the Eurasian steppe, and one smaller population western to the Pyrenees inhabiting the Iberian peninsular [10]. So the hypothesis there was an Iberian wild horse that slenderer and taller than other members of Equus ferus seems at least possible. But is there evidence for it? This is hard to tell because it is difficult to tell wild horses apart from domestic horses in the subfossil record of the late Holocene without genetic testing. I know that d’Andrade did measurements with skeletal elements of the Sorraia and supposed wild horses, and I do not dispute his professional competence, but I am not sure if it was possible to safely distinguish between domestic and wild horses back this time (except for some unambiguous cranial features, such as enlarged eyes and a reduced brain case). Furthermore, the Sorraia remains he worked with were prior to the bottleneck event, so modern Sorraia might display different features due to genetic drift. I know of Ebhardt’s division of 4 predomestic subtypes of Equus ferus that includes one type resembling the Sorraia, but it seems that there is low scientific support for it in modern scientific literature (although it is popular among hippologists). I haven’t seen any recent studies using or referring to it. Of course it is likely that different environments had a different impact on wild Equus ferus over its large geographic range, but the proposal of regionally differentiated body conformations should be grounded on a osteologic basis or on reports of people having seen these animals in flesh. Of course it is possible that the western wild horse was regionally differentiated, but other large herbivores with a large geographic range such as Red deer or moose don’t display any radical differences in body conformation when comparing their various subspecies (island dwarfism in case of Red deer on Sicily is another story), so it does not imply it.
Sorraia.org claims that the Danish wild horse skeleton from 11.100 years BP is identical in proportions and skull shape to Sorraias. I do not really see that, it would be more conclusive for me if it would be a member of the przewalskii clade and its head is clearly more robust (sorraia.org provides a superimposition with a Sorraia skull photo from d’Andrades work, but this historic skull hardly fits modern Sorraia’s heads because the lower jaw is more robust; perhaps an effect of the genetic bottleneck?). I will do a life reconstruction of that skeleton soon to get a better idea of what it might have looked like in life. Nevertheless, not all Sorraia have a gracile head. Looking at this dental, claimed by sorraia.org to be an example of a gracile-jawed wild horse remain, and comparing it with an Exmoor pony skull from Sue Baker’s book, it appears to me that this wild horse had a skull only insignificantly longer (=more gracile) than the Exmoor. To affirm the question if there are definite wild horse remains that endorse the hypothesis that there were predomestic horses that had a body conformation similar to the Sorraia, a new osteometric study comparing a representative sample of confirmed wild horse and Sorraia skeletons would be needed. Sorraia advocates sometimes also refer to Equus stenonis, but this is a huge and most likely incorrect stretch, as E. stenonis was only distantly related to E. ferus and disappeared in the late Pliocene. Furthermore, their hypergracile skulls have a concave profile, the opposite of what we see in the Sorraia.

Skull of a Sorraia Mustang mare ©Lynne Gerard
Skull of a Sorraia Mustang stallion ©Lynne Gerard
While looking for good Sorraia skull photos to compare them with wild horse skulls, I stumbled across something interesting. Lynne Gerard published photos of skulls of two of her Sorraia Mustang individuals, a stallion and a mare, on her blog. While neither of the photos shows a lower jaw in a useful lateral perspective, we are able to see that the size of the orbital openings is well larger than in wild horse skulls (I am using the Danish specimen, and in the lack of other useful European species, also American wild horses as a reference, which where probably conspecific). The increase of the eye size, as well as a reduction of brain size, is a typical artefact of domestication, visible in virtually any domesticated larger mammal, and shared by other domestic horses – even primitive ones like the Exmoor pony.

Conclusion

I want to make clear that I am not biased against the Sorraia. The idea that Iberia had a unique subtype of the European wild horse differing in having a taller, much slenderer body than other wild horses is exciting, but I think the evidence for that is rather thin. And if there was, I do not think the Sorraia would be a predomestic remnant population of this type, but more likely a domestic breed with introgression of these horses. Nevertheless, I think that the western Iberian wild horse was not drastically different from the wild horses formerly inhabiting the Pyrenees and Northern Spain as described by C. H. Smith, unless there is there is evidence for the contrary – I think this is the most parsimonious and most likely assumption.  An osteometric evaluation of confirmed wild horse remains from various places of Europe would be very helpful to gain information about the appearance of Holocene wild horses and regional diversification.
The hypothesis that the Zebro was a Sorraia-type horse rather than a wild for feral ass seems far-fetched as well. If this was not the case, then I assume that there was no feral population with a long history in the area d’Andrade spotted those nebulous horse herd, as there are no other references to it. Most likely he saw an abandoned farm horse herd. The Sorraia itself is not older than 80 years, since it was created in the year 1937 by collecting local farm horses resembling those spotted by d’Andrade. Genetically, there is no solid evidence for the Sorraia having a special status on the domestic equine tree. Absence of evidence is no evidence of absence, but proposals like the Sorraia being a predomestic horse should have a more solid basis than this.
It seems that the Sorraia breed is “just” a domestic horse breed, albeit a hardy and robust landrace. In my personal opinion, the Sorraia and Lustano as much as similar mustangs like Kiger, Sulphur and Pryor might all derive from a historic domestic breed/type of horses with an appearance very similar to their modern counterparts, what is inferred by their very similar phenotype and also genetic similarities. 


Literature

[1] Bunzel-Drüke, Finck, Kämmer, Luick, Reisinger, Riecken, Riedl, Scharf & Zimball: Wilde Weiden: Praxisleitfaden für Ganzjahresbeweidung in Naturschutz und Landschaftsentwicklung. Arbeitsgemeinschaft Biologischer Umweltschutz
[2] Jansen et al.: Mitochondrial DNA and the origins of the domestic horse. 2002
[3] Luis et al.: Genetic diversity and relationships of Portuguese and other horse breeds based on protein and microsatellite loci variation. 2007
[4] Luis et al.: A lost Sorraia maternal lineage found in the Lusitano horse breed. 2006
[5] Lira et al.: Ancient DNA reveals traces of Iberian Neolithic and Bronze Age lineages in modern Iberian horses. 2009
[6] Royo et al.: The origins of Iberian horses assessed via mitochondrial DNA. 2005
[7] Cieslak et al.: Origin and History of Mitochondrial DNA lineages in Domestic horses. 2010
[8] Ludwig et al.: Coat colour variation at the beginning of horse domestication. 2009
[9] Pruvost et al.: Genotypes of predomstic horses match phenotypes painted in paleolithic works of cave art. 2011
[10]Cieslak et al.: Coat colours and mitochondrial lineages of ancient horses to document domestication. 2011

Wednesday, 25 December 2013

Bad Heck cattle Pt. II

Remember my post on some blatantly un-aurochs-like Heck cattle? Like I wrote, it is not my intention to bash the whole Heck cattle breed or to accuse breeders of having done something wrong. I merely compare the cattle to the archetype they are supposed to resemble. You find a lot of very bed Hecks in zoos, sometimes also on private farms. Here another little collection of Heck cattle that do not resemble and are in my opinion not useful for breeding-back: 


Almost no sexual dimorphism, domestic body, mediocre horns
Rheinauer Wald, Germany
Grayish coat, domestic body, short barely curved horns
Tripsdrill (Münster), Germany
Weakly expressed sexual dimorphism, domestic body, horns too small and wrong shape
Is that a bull or a cow? Sometimes really hard to tell in Heck cattle
Although the leg length and the skull is acceptable,
the sexual dichromatism is too reduced, horns are way too small and wrong-curved

Monday, 23 December 2013

Some good Maronesa

The portuguese cattle breed Maronesa is certainly one of the most aurochs-like breeds around today, and rivaling with Lidia for being No. 1 of the aurochs-like Iberian breeds on my personal list. 
Maronesa is very precious for several reasons. First of all, let's have a look at its phenotype. It is one of the very few European breeds in which most individuals have a perfectly correct aurochs colour that is really stable in the breed, only a number of cows have a reduced dichromatism, and some bulls might lack the dorsal stripe. Their curly forelocks give them an especially aurochs-like appearance, since this was a prominent facial feature of the aurochs. The horns of Maronesa bulls always face inwards, in some bulls to a very aurochs-like degree. The horns of the cows vary in shape, many have horn tips facing too much outwards to fit the aurochs (having a corkscrew-like shape), but there is still a number of female Maronesa with inwards-facing horns. Being a draft breed, many have a well-developed humps - bulls as much as cows. The body shape varies from being long-legged and slender to less long-legged. Bulls tend to be more longish than cows, I haven't seen a Maronesa bull with a squarely built body like in the aurochs yet. Maronesa also has a very prominent sex difference regarding size and body shape/proportions and horn thickness. 
Their beautiful colour, forelocks, sexual dimorphism and often-good horns shouldn't let us forget their phenotypic deficiencies though; Maronesa tends to be a small breed, as small as Heck cattle or smaller. However, still some quite large animals, like bulls reaching 160 cm, appear. Maronesa is a fairly short-faced breed. Most animals have a concave head profile and a very shortened head, some bulls can be called "bulldog faced". The horns of many Maronesa are good and useful for breeding-back, but one aspect - the orientation relative to the skull - is suboptimal in most individuals. I estimate that the horns of Maronesa are about 20° lower than in the aurochs. 
But as you know, appearance by far isn't everything. Maronesa often live freely all around the year, tolerate large amounts of precipitation and cold temperatures, and even have to defend themselves against wolves on occasion. So they are close to being being semi-feral in my opinion. 

Now, here you find a selection of photos of Maronesa individuals that are quite aurochs-like or at least have an appealing appearance to me. 


Although there should be around 5000 Maronesa (2000 individuals more than Heck cattle!), their numbers are falling. Moreover, their primitivity is at the danger of getting successively diluted by crossing with more derived breeds. Luckily breeding-back bought at least some herds to save and use their primitive phenotypic and ecologic features for "reconstructing" the aurochs. Tauros Project has one Maronesa herd in the Netherlands, and there is a herd in the Faia Brava reserve in Portugal too, although it is still nebulous to me if that herd is going to be part of the breeding-back project. I hope more herds are to follow. Numerous zoos in Central Europe have (often quite non-aurochs-like) Heck cattle displayed as "aurochs". Why not importing and showing some Maronesa instead? It would not be more of false labeling than with Heck cattle and it would contribute to secure good animals for breeding-back. I also hope that more grazing projects will use primitive breeds such as this one in the near future. 

By forming herds exclusively composited of very aurochs-like Maronesa that would be selected for 

  • inwards-facing horn tips in both sexes 
  • not too short skulls
  • tall and slender bodies
  • well-expressed dichromatism
  • large body size 
an even more spectacular lineage of that breed could be created, especially if they would be kept under semi-feral conditions. Crossing in of Sayaguesa and Chianina would help to increase the body size, skull length and long-leggedness significantly. The undesired features of Chianina (colour dilutions and small horns) would require to use them in a separate herd where their negative features are out-crossed by using the second Mendelian rule. An upgrade of horn dimensions would be necessary as well. Barrosa would contribute yet more unwanted colour features and their horns are not that thick in cows, so Wörth Heck cattle might be a useful decision. But perhaps only in few doses to not bring in their dairy cattle body shape into the whole population. 

Sunday, 22 December 2013

Comming soon: Cattle coat colours and Sorraia

I have some articles in preparation but not the time to gather enough information for satisfying quality at the moment, or simply not enough time to write them. But at least one of the two articles mentioned in the headline will follow next week: an introduction to the genes involved in the expression of the aurochs' coat colour and the domestic mutation we see in many cattle breeds, and my approach to uncover what is behind the numerous anecdotes surrounding the Sorraia horse from Portugal. Stay tuned! 


Saturday, 21 December 2013

Spotting free-ranging Exmoors in Devon

The Exmoor National Park is, not surprisingly, populated by several herds of free-ranging Exmoor ponies. They are not feral since they are caught and checked by the Exmoor Pony Society every year, and the breeding stallions are chosen by man. In my opinion it is best to call them free-roaming or semi-feral. However, they do not get supplementary feeding, and few decades ago they were known to be very shy and avoided regions of the NP that was regularly visited by humans. Now, as the tourism and interest in them increased, they get increasingly accustomed to human presence. 
I visited the ENP in summer of 2011. The beautiful landscape of southern England was shaped by man for centuries, yet this park-like partly forested partly grassy landscape is what might be quite reminiscent of what may have been Europe's original home to its large grazers. It was not easy to find the Exmoors because of their excellent camouflage and shyness (while the heterogeneous Dartmoor ponies or other free-ranging ponies you see in England are easy to spot). But finally I came across a small group of four adult mares and one male foal. 


The herd tolerated me approaching to a distance of about 6 metres, then they started to get wary and walked about 20 metres away from me and started grazing. It was very interesting and enchanting to look for and see free-ranging herds of such beautiful primitive horses in a more or less natural environment. Let's hope Europe will have more of such places again in the near future! 

Monday, 16 December 2013

The skulls of two Taurus bulls


As promised, here is my post on the two Taurus bull skulls from the Lippeaue that were kindly sent to me by Matthias Scharf from the ABU – many, many thanks!
I tried to evaluate everything useful that I was capable of and took a lot of photos and measurements and compared them with aurochs skulls.

But first, a little introduction to the bulls the skulls are from.
"Luca" (Heck x Chianina) Photo © ABU
The larger one is from a bull named Luca, he was one of the first cross bulls produced by the ABU and was Heck x Chianina. He may have been about 160 cm tall at the shoulders (my calculation based on photos and the actual skull), had a diluted colour due to its Chianina ancestry and was used as a breeding bull in the Hellinghauser Mersch herd until he died 3 years ago. He is the father or grandfather of numerous individuals at Lippeaue, very good individuals like Lamarck among them, who replaced him as breeding bull.

The second skull you might already know from my report of my trip to the Lippeaue, it was one of the skulls I viewed in the field. It’s from a bull called Latino – 50% Sayaguesa, 25% Lidia, 25% Heck. He was selected out because of his comparably small size (I estimate a height of 145 cm for him based on photos) and his nervous and aggressive behaviour (I’m not saying this kind of behaviour is “unnatural” or exaggerated, but I understand that such bulls are extremely difficult to handle). He had a quite aurochs-like overall appearance though, and I suspect that he is the father of this bull I saw at neighbouring Pöppelsche.

And now the skulls:

Luca

Skull length (from frontal bone to nasal bone): 49 cm
Skull length (from frontal bone to premaxilla): 59 cm
Breadth from eye opening to eye opening: 25,3 cm
Breadth between the bases of the horns: 23 cm

Horn cores
Length (outer bow): 63,3 cm
Circumference at base: 31,3 cm
Span from tip to tip: 77 cm

Horn sheath
Length (outer bow): 79,5 cm
Circumference at base: 34,5 cm
Span from tip to tip: 70 cm
Maximum Span: 82 cm

Horn angle relative to the skull: 80°

Latino



Skull length (from frontal bone to nasal bone): 44 cm
Skull length (from frontal bone to premaxilla): 54 cm
Breadth from eye opening to eye opening: 23 cm
Breadth between horn bases: 28 cm

Horn cores
Length (outer bow): 44 cm
Circumference at the base: 28 cm
Span from tip to tip: 80 cm

Horn sheaths
Length (outer bow): 61 cm
Circumference at the base: 30,5 cm
Span from tip to tip: 71 cm
Maximum span: 85 cm

Horn angle relative to the skull: 65°

With 65°, Latino’s horn orientation is within the variation we see in the aurochs. With 80°, Luca’s horns are too upright, altough the Vig bull with unusually upright horns comes close.
It was interesting to see the difference in size and shape between horn sheath and horn core when I detached them. The horn sheath of Luca adds 25,6% to the length of the horn cores, while that of Latino adds 38,6%. It adds 23,3% of thickness in Luca and 27,3% in Latino. Comparing the shape of the horn sheaths with the cores I realized that the sheaths have a much more pronounced curvature. Luca’s sheaths resemble the shape of many aurochs horn cores and curve inwards, but his horn cores are more straight and show almost no curve towards each other. The same is the case with Latino’s horns and probably every bovine in the world. I therefore see two consequences: a) aurochs horns were longer and slimmer at the tips than horn bones indicate and their curvature was more extreme, perhaps similar to this maronesa bull, b) we should consider that if an individual has horns sheaths that look like bony cores of some aurochs specimens, the horns are not identical because its cores would be shorter and less curved.



The superimposings with photos of aurochs skulls were very helpful to see differences and similarities. I did them in lateral (side) view and dorsal view (when the snout is vertical to the ground). I always took the distance between the caudal end of the frontal bone and the eye openings as reference since the length/breadth ratio of the area from the caudal end of the frontal, the imaginary line between the eye openings and the horn bases in both skulls was the same. It showed me that not the entire skull is shorter, but mostly the snout. Also, the eye openings are slightly enlarged in the Taurus bulls, but not much. The skull of the Sassenberg bull is an exception, which was a really long-snouted and small-eyed old specimen. Down below you see the amount of skull length reduction in the two Taurus skulls in respect to the aurochs skulls.


Prejlerup
Berlin
Luca
-4%
-7%
Latino
-12%
-5%


Lund
Vig
Sassenberg
Baikal
Luca
-8%
-7%
-25%
-7%
Latino
-19%
-13%
-34%
-10,3%

According to Nehring 1886 the usual skull length of the investigated aurochs skulls varies between 64 and 72 cm. I wonder whether “skull length” means from the caudal end of the frontal to the cranial end of the nasal or the premaxilla. Let’s assume the former is the case. The arithmetic mean of the relative length difference between the aurochs skulls and the Taurus skulls is about 13%. Increasing the skulls absolute length by the factor 1,13 results in 49,7 and 55 cm. That means that the Taurus skulls are not only shorter but also smaller than usual aurochs skulls, what isn’t surprising considering that the individuals themselves were smaller than aurochs (Latino) or had a proportionally smaller skull (Luca). Also, the nasal bone seems to be shortened relative to the length of the premaxilla in Luca. Interestingly, the nasal bone has two bulges in both skulls instead of one proximal bulge as in the aurochs, what was not visible in the living animals.
Having had a look at the occipital bone, I recognized that the fossae for the attachment of neck muscles forming the so-called neck crest in taurine bulls, wisents, cape and water buffaloes are about as deep and pronounced as in aurochs skulls. This implicates that the crest in the aurochs was of similar size as in bulls of less-derived taurine breeds, what simply makes functional sense.

I also did superimposings with photos of the two bulls in flesh, but they mostly did not work out well because of the perspective. However, one with Luca in profile is quite ok, shown down below. It is interesting to see that the eye sockets protude greatly from the skull in Taurus cattle or Lidia (and probably most other primitive cattle) and the aurochs, but in the living animal the eyes don’t stick out that much, so it probably looked the same in the aurochs.

I also did one with a Maronesa bull in which I shortened the skull of Latino in order to find out how the skull of a short-faced breed would look like compared to the aurochs.


This gif shows Latino’s skull layed over the Maronesa bull’s head, and a version of Latino’s skull with shortened snout to fit the Maronesa’s head, and it lines up very well with the animal. The result was a skull that is 10% smaller than Latino’s head. Now comparing it with the Vig bull, it means that the Maronesa’s head is 21,3% shorter. In the case of the very long-snouted and small-eyed Sassenberg bull (which already had a big difference with Latino’s skull) we get a difference of 59%, what sounds extreme but still plausible. One could argue that this bull is subadult and still growing, but this bull is certainly around 3 years old, and features such as the snout and horn size don’t increase significantly in proportion after that age, although the bull continues to get larger and heavier overall.

With all the information the comparisons between aurochs skulls and my skulls I tried to do a rough reconstruction of an average bull aurochs head. It is based only on what the bones tell me, and focuses on proportional issues and horn shape. I increased the skull/snout length by about 15%, slightly increased the horn size (the relative horn core length of Latino and the Prejlerup skull is identical, but other aurochs skulls have larger horns) and added the parts of the curvature that is missing in his horns (I didn’t put much artistic effort into it, it’s main purpose is to show the proportional differences).

Having evaluated these two Taurus bull skulls and taken note of similarities and dissimilarities, which cattle breeds have heads identical to that of aurochs? We don’t know until a rigorous evaluation of their cranial features is done, using several aurochs skulls for comparison, but based on the characters we can tell from bulls in flesh, some Maremmana, some Lidia (I did a superimposionwith a Lidia steer skull and the Berlin bull here), some Pajuna and some Sayaguesa have bulls with heads looking pretty reminiscent of the aurochs.