The wisent hybrid origin hypothesis is outdated

Traces of hybridization among closely related species have been found everywhere it was looked for, including the genus Homo. Bovines are no exception to this. About ten years ago, it was proposed that the wisent, which I refer to as Bos bison bonasus here, originated as a hybrid of aurochs and steppe bison, Bos bison priscus, and inherited around 10% of its nuclear genome from aurochs. Now, ten years later, it has been demonstrated that this hypothesis was based on premature conclusions and partly also the result of methodological problems. However, the rebuttal of the hybrid origin hypothesis did not nearly attract as much attention as the paper by Soubrier et al., 2016, so that many still think this is the current state of research. Considering that I wrote a post when the paper came out titled “Confirmed: the wisent is an aurochs hybrid” back then in 2016 that is still online, I feel obliged to present a (hopefully) up-to-date picture of the current research on the origin of the European bison. Let’s dive into the literature.

 

A possible hybrid origin for the wisent was first proposed in 2004 by Verkaar et al., when it was surprisingly revealed that the wisent does not cluster with American bison and yak on the mitochondrial genome but with taurine and indicine cattle instead [1]. This would have suggested that bison bulls repeatedly mated with cows of the cattle lineage, which, given the time and region, would have been aurochs, giving rise to a bison that has “cattle-line mitochondria”. Then, more than ten years later, this hypothesis was endorsed by Soubrier et al., who executed a test of 10.000 single nucleotide polymorphisms and concluded that 10,9% of the nuclear genome of the wisent stem from aurochs [2]. At that time, I found that convincing, given that wisent sometimes clearly show the primigenius spiral in their horns and have a shorter body length than American bison, traits that I associated with the aurochs. But, as we will see, the results of Soubrier et al., did not remain uncontested for long.

 

The first critical response to mention would be Wang et al from two years later [3]. They find no evidence of 10% nuclear aurochs ancestry, and also found that parts of the nuclear genome show a similar phylogeny as the mitochondrial genome. The authors consider it more likely that the evolutionary phenomenon called incomplete lineage sorting is responsible for the weird mitogenomic position of the wisent on the phylogenetic tree.

ILS is a rather cool phenomenon. It happens when there are polymorphic genes (with more than one allele) in an ancestral population and the population splits up and undergoes cladogenesis. One branch would inherit only one allele of the polymorphic gene (let’s call it “A”), while the other population still has the alleles A and B. Then, this other population splits up too and one filial population retains only A, and the other one only B. What would the result on a phylogenic tree be if you look at this gene? The population that branched off first would group together with the population that retained A, while B would result as the outgroup to the other two – although this is not what happened in reality. This is incomplete lineage sorting. In fact, it is not rare that mitogenomes show phylogenies that are inconsistent with those inferred from nuclear DNA [3]. Wang et al. find that ILS is a more plausible explanation for the mitochondrial position of the wisent and more consistent with the genomic structure of the bovine [3]. The authors also caution that phylogenies based on single genes can be misleading because of ILS [3].

 

What about the 10% aurochs ancestry on the mitochondrial genome? It seems that this number is erroneous because an inadequate method was used [4]. Soubrier et al. looked at fewer than 10.000 SNP, which is a rather scarce sample, and did an f4-statistics analysis with them, which is how they arrived at the 10,9% aurochs ancestry. Grange et al. point out that this might be problematic because f4-statistics assume an ancestral population that is polymorphic for the SNPs, while the sample the authors used were from the BovineSNP50 chip that contains SNPs for differentiating individuals of modern cattle breeds [4]. With another approach, namely the Approximate Bayesian Computation (ABC), Grange et al. arrive at a 97,2% probability that there is at least one percent aurochs ancestry in the wisent genome, which is significantly lower than the results of Soubrier et al. [4]. The method employed by Soubrier et al. also results in ancient wisents, wisents from 1911 and Pleistocene priscus being closer to each other than the wisent from 1911 to modern wisents, indicating that something is methodologically wrong here [4].

Weçek et al. did a whole genome sequence analysis with modern wisent genomes as well as four historical samples and found that only 2,4 to 3,2% of the wisent genome seem to come from the aurochs/cattle lineage and the genomic structure suggests that it occurred a long time ago, therefore they consider it possible that this reflects aurochs introgression but they note it requires more research [5].

 

If the wisent is not an aurochs hybrid, where does it come from? One hypothesis that was postulated is that it is a descendant of late surviving B. b. schoetensacki. Bone remains from the Sirejol cave from the Upper Pleistocene have been tentatively morphologically assigned to this form previously, and a phylogenetic analysis revealed that the material belonged to the Clade X proposed by Soubrier et al. and Bb1 proposed by Massilani et al. (2016) [6]. The authors of Palacio et al. therefore conclude that schoetensacki corresponds with this mitochondrial clade [6]. The presence of schoetensacki in the Late Pleistocene would imply a ghost lineage spanning over a 500.000-year period, since this variant disappears from the fossil record shortly after aurochs enter the European continent in the Middle Pleistocene.

However, the morphological assignment of the Sirejol material to schoetensacki was likely premature, as a morphometric analysis taking sexual dimorphism into account rejects that this material was of a late surviving schoetensacki bison [4]. The much more basal B. b. schoetensacki clusters morphologically with the earlier B. b. menneri, but not with steppe bison and wisent.

 

So the wisent is not a descendant of the European Bos bison schoetensacki either. What we can say is that molecular clock data suggests that the lineages of B. b. bonasus and B. b. bison diverged around 215kya (roughly the same time when B. b. priscus first entered America) and gene flow ceased at 102kya [4]. 57 ancient genomes suggest that late Pleistocene steppe bison originated from the north while wisent originate from a refuge in the southern Caucasus after the most recent glacial maximum [7]. The American bison is nested in the priscus tree on the mitogenome [4], so we can be rather confident that B. b. bison descends from B. p. priscus in some way (either directly or over B. b. latifrons).

 

The two mitochondrial clades Bb1 and Bb2 are present in the late Pleistocene in Western Europe and the Caucasus, they are sister clades to the modern wisent clade [7,8]. It seems that while aurochs retreated southwards during glacial periods, ancient bison stayed in refuges dispersed over Europe [7,8]. This fragmentation and isolation could explain how the ancestors of the wisent split off from the rest of late Pleistocene bison around 215kya. While the more cold-adapted ancestors of the steppe bison/American bison clade probably remained in the north, the ancestors of the wisent might have stayed in their refuges in the Caucasus and parts of Europe.

 

As you see, the situation is much more nuanced than my post from 2016 suggests. It is a reminder for me that the last word is never spoken in science, contrary to what the title of my 2016 post suggests (“confirmed”, a word I should not have used).

If I missed any relevant papers in this post, I'd be grateful if it could be pointed out to me. 

 

Literature

 

[1] Verkaar et al.: Maternal and paternal lineages in cross-breeding bovine species. Has wisent a hybrid origin? 2004.

[2] Soubrier et al.: Early cave art and ancient DNA record the origin of European bison. 2016.

[3] Wang et al.: Incomplete lineage sorting rather than hybridization explains the inconsistent phylogeny of the wisent. 2018.

[4] Grange et al.: The evolution and population diversity of bison in Pleistocene and Holocene Eurasia: sex matters. 2018.

[5] Weçek et al.: Complex admixture preceded and followed the extinction of wisent in the wild. 2016.

[6] Palacio et al.: Genome data on the extinct Bison schoetensacki establish it as a sister species of the extant European bison (Bison bonasus). 2017.

[7] Massilani et al.: Past climate changes, population dynamics and the origin of Bison in Europe. 2016.

[8] wisenthybrid3

[9] Zver et al.: Phylogeny of Late Plesitocene and Holocene Bison species in Europe and North America. 2021.

 

Did the wisent evolve because of humans?

For this post, I created the new post category “wild speculations”, because it is indeed a wild speculation. Some species even evolved as a result of human activities. One example for human-induced speciation would be the plant Erythranthe peregrina, which is a hybrid of two species introduced to Britain, E. guttata and E. lutea, which hybridized, created a sterile hybrid which experienced allopolyploidization (doubling of the genome) and produced a fertile hybridogeneous species. It was discovered relatively recently (2011). Without human intervention, this species would not exist. It is also possible that other kinds of human intervention, such as wiping out species, can result in a speciation event over a longer period of time in evolutionary terms because the niches that become vacant have potential for the evolution of new species. I have the suspicion that it is possible that the wisent might be such a case.

The story begins around 600kya, when there was only one Bos species in Europe, Bos (bison) schoetensacki. Around that time, a second bovine species migrated to Europe, either by island hopping from Africa or via the continental route from western Asia, the aurochs. Only a few millennia after the aurochs arrived in Europe, B. schoetensacki disappeared from the fossil record. I think it is quite possible that B. schoetensacki was outcompeted by the newly arrived aurochs as both bovines must have occupied a similar niche and the extinction shortly after the arrival of the aurochs is just as suspicious as the fact that bison subsequently were absent from interglacial faunal assemblages of Europe until the very late Pleistocene around 13kya, when bison (now in the form of the wisent) re-entered the interglacial megafauna assemblage. I call that the “bison gap” (roughly 600kya-13kya). If the aurochs outcompeted bison in Europe, why did they rejoin the interglacial fauna and why only so recently? B. bison priscus, which was most likely the ancestral form of the wisent, was present in Europe during all of the recent glacial periods. So, it could have evolved into an interglacial bison type much earlier, right after the extinction of B. schoetensacki if the aurochs did not outcompete bison in Europe – if it did, it is an open question why this competition was not a factor anymore at the end of the Pleistocene and during the Holocene.

Several thousand years earlier, there was another event that had an impact on the European megafauna: Palaeoloxodon antiquus and Stephanorhinus hemitoechus died out, most likely because of hunting from humans. Elephant extinction reduced competition for other grazers, at the same time forest growth became more common. Aurochs could not invade denser forest while bison are adapted to consume more wooden vegetation and can invade denser forest. This might have created new ecological space for bison to re-enter the interglacial faunal assemblage.

 

This guess is impossible to verify, but I think it must have one or several reasons why bison were absent from the European interglacial faunal assemblages for over 500.000 years.

 

If this guess is true, it would illustrate how nature is dynamic and might respond to anthropogenic impacts not necessarily always in a diversity-reducing way but sometimes also in a diversity-increasing way.

 

Aurochs anatomy revisited

In the latest post, I reviewed much of the ancient and historical aurochs depictions and what they tell us.

Here are some conclusions in this regard:

 

A shoulder hump present and visible, more so bulls than in cows but present in both sexes, but not nearly as prominent as in bison – this is also in line with the fact that the shoulder spines are not as high in the aurochs as in bison.

The dewlap likely had almost a gap in the throat region, similar to what we see in banteng.

The pelvis was probably slanted to some degree; we see this also in other wild bovines and this is likely basal for Bos.

Adult bulls probably made a massive and somewhat hefty impression as they are often portrayed in that fashion. Likely there was no edge between the neck and the hump in bulls in the “default position” of the neck.

 

With this information, I attempted some new reconstructions, also trying to avoid my common mistakes I tend to make when I reconstruct the aurochs.

 

Most puzzling to me is the length and shape of the trunk. Let us look at the length first.

When I do my reconstructions, I always consider the cartilage between the leg elements that is missing in the skeletons. This makes the legs longer in life than what they appear in the skeleton. There were of course also the intervertebral discs between the vertebrae, which I also considered but assumed that most mounts take them into account. Looking at dissected cattle, I think, however, that some skeletal mounts might underestimate the amount of cartilage between the vertebrae. This means that the ratio between shoulder height and trunk length was certainly not exactly as in the skeletons. The exact ratio in life is, however, hard to determine without accessing the skeleton directly. Some guesswork is involved, and this is where aurochs depictions can be helpful. Not in detail, but they do transport the overall impression the animals must have made. And if the artwork is bulky, the animal certainly was not gracile.

There is also one sentence in Schneeberger’s report from Jaktorow that provides a clue. He writes that bulls were not as long as the cows, which is the only written account of the body morphology of the aurochs that I am aware of. The fact that he wrote cows being “not as long as the bulls” could indicate that he found the bulls to be somewhat longish. But not necessarily. However, the way the remark is put is interesting.

 

The same goes for the shape of the trunk. With the exception of the Siga verde bull engraving, none of them show bulls with an overly slender waist as in young fighting bulls.

 

Putting the evidence together, I made three sketches based on three different approaches.

This one is based on the photo of a Holstein bull. I manipulated the proportions of the bull on the photo in order to make it fit the Store-damme skeleton:

 

This one is based on the Torsac-dirac skeleton, using ancient depictions such as the one from the Romito cave, Siga verde or Dordogne as a guidance:

 

The last one is based on the Store-damme skeleton:

 

 

While the results are not all too different from each other, I think the lower sketch is the most plausible one, it resembles the Lascaux cave paintings quite well while also matching the anatomy of extant wild bovines. It also resembles the reconstruction of the Sassenberg bull by Tom Hammond in overall morphology. If two artists come to the same result with different skeletons and methods, we might be on the right track. 

 

 

 

What ancient and historical depictions of the aurochs tell us

When trying to infer the morphology of the aurochs from all available evidence, we do reach a point where comparisons with living relatives (wild bovines and domestic cattle) will not get us any further because there are limits to what the skeletal morphology tells us about the surrounding soft tissue. This is where ancient and historical depictions made by people who actually encountered the living animals become helpful. With this post, I want to do a review of what I think these depictions tell us about the morphology of the wild bovine.

 

This post features some images; if you are the copyright holder of these images (in those where the copyright is not yet expired) please notify me if you want me to remove the images in question.

 

-) Cave paintings and prehistoric engravings

 

All prehistoric depictions show a rather short dewlap in both sexes that becomes very short in the throat region. This shape of the dewlap is similar to what we see in banteng. The backline is almost always slightly depressed in the middle of the trunk, creating an S-shape. Bulls are often shown with a rather massive and sometimes longish morphology, most notably the engravings at the Grotta de Romito and Dordogne.

The hump is indicated in most ancient depictions, but not nearly as prominent as in depictions of steppe bison. There is mostly no edge between the neck and the shoulder hump in the bulls, similar to what we see f.e. in Sayaguesa but unlike what we see in Lidia and most other domestic bulls.

 

-) The Zliten mosaic

 

It shows a rather athletic bull that might be an aurochs with a morphology similar to young Lidia bulls.

 

-) The Vapheio cup

 

The bulls on the Vapheio cup from ancient Greece show curly hair between the horns and rather longish trunks. The waist is not as slender as in young Lidia bulls and the dewlap is again very short.

 

-) Bestiary of the British Library 12F XIII

 

This is the only depiction showing what might be a “mane” like in Lidia, Chillingham and some OVP Heck bulls. The trunk is rather short and narrowing towards the hips and the dewlap is short.

 

-) Aurochs hunt depiction from 16^th century of Nuremberg

 

It shows a bull with an athletic body with a narrow waist and a short trunk.

 

-) von Herberstein’s taxidermy

 

There are two contemporaneous drawings showing Sigismund von Herberstein’s aurochs taxidermy, one from 1556 and one from 1557. These drawings, however, have to be viewed with caution; not because they are stylized, all contemporaneous aurochs depictions are, but because it is based on a taxidermy and we do not know how authentic this taxidermy was. Von Herberstein was also in possession of a wisent taxidermy that was drawn by the same artist at the same time, and the wisent drawing is rather accurate, so the taxidermies might have been quite authentic and so might be the drawings.  

 

 

The 1556 drawing shows a massive body, short dewlap with a similar shape as in cave paintings,a hump not discernable (while illustrated very clearly in the wisent drawing), curly hair on the forehead, a slightly slanted pelvis as in banteng and gaur, which I believe to be the basal condition within the Bos clade.  

 

The 1557 coloured drawing shows a short but massive trunk, slightly slanted pelvis, a hump that is slightly indicated, dewlap short but more than one “flap” under the throat (more like domestic cattle) and the same curly hair as in the older drawing.

 

-) Charles Hamilton Smith’s aurochs

 

CHS’s copy of the lost “Augsburg painting” shows a very short dewlap with two indicated flaps in the throat region, a deep chest and relatively trunk narrowing towards the hip, a hump that is only indicated and neck muscles set apart from the hump. The original is said to have shown a coarse black coat.

 

I leave this analysis as it is for this post, my conclusions for the aurochs’ anatomy will be covered in an upcoming post that will also include some new reconstructions avoiding my old mistakes. Stay tuned.

 

 

 

 

Flaws and inaccuracies in my aurochs reconstructions and what we do not know

I did several dozens, perhaps roughly one hundred, aurochs reconstructions since I got into this topic in 2011. Some of them I nowadays consider outdated or not sufficient because in the early days I was not that experienced in drawing bovines. But also my recent reconstructions do have some flaws sometimes. I am still trying to accomplish the “one perfect aurochs reconstruction”, which is probably impossible to achieve (or maybe I am overcomplicating this issue). Anyway, I always appreciate constructive criticism, also because I am never 100% confident that the respective reconstruction shows what the aurochs really looked like. Most of my aurochs reconstructions are floating around on the web, often in places I don’t know, which makes it impossible for me to put a disclaimer on those that have apparent flaws. That is why I decided to make a post summarizing common flaws and inaccuracies that may happen to my reconstructions. If you have any flaws to add to this list, be it in general or to a particular reconstruction, please tell me, it is highly appreciated.

 

-) Exaggerating the morphology/the hump

 

Since I copy the proportions directly from photos of the skeleton in profile, and for head reconstructions I track out the skull, the proportions themselves should be alright in most of my reconstructions. However, I think I have a tendency to show certain aspects of the morphology in a too pronounced fashion, often due to a fear that the result looks too domestic. It is like I subconsciously think “I’ll do an anti-domestic cattle to be on the safe side”. But taking it to the other extreme is not good either.

In some of my reconstructions, the hump and the Musculus trapezius are very pronounced. That has two reasons: some aurochs skeletons, such as the Prejlerup bull, have rather tall spines that are not much shorter than in the wisent and I am not sure how pronounced it would be in the living animal. Some Lidia bulls, mostly those I consider less-derived, have very pronounced humps with well-developed trapezius muscles. In others it is less developed. Looking at the skeleton of a Heck bull (go here), it seems that its shoulder spines are not much shorter than in the Store-damme bull skeleton, and Steinberg/Wörth bulls do have a hump but not nearly as developed as in my reconstructions. Most contemporaneous depictions do show a hump, but not as super pronounced as in bison for example. If it was a very prominent trait in the living animal, it probably would show in the cave paintings/engravings.

I also tend to reconstruct the waist too slim because I often have used young Lidia bulls as an analogue. Looking at most wild bovines (fully grown ones) as much as ancient aurochs depictions, this might be inaccurate. Surely, the aurochs’ waist was most likely not barrel-shaped as in domestic cattle, therefore “more hump, less rump” should be the guideline but sometimes I exaggerate it. But I think it got better in my recent reconstructions.

 

-) Underestimating the bulk of the animal aka “shrink-wrapping”

 

This is a pitfall that happened in my 2023 sculptures. I noticed it and paid attention not to repeat that mistake in my more recent sculptures, but it also happened in some of my drawings. This is ironic, because I opposed “shrink-wrapping” in paleoart as early as 2008, when the term was not even invented yet. Looking at the bones too much makes one forget the bulk of soft tissue that surrounded them in life.

But the problem also is that I am completely uncertain how bulky the trunk of the aurochs was exactly. This differs among extant wild bovines and also changes with the individual age. But in general, most of my reconstructions are too light-weight compared to other wild bovines and archaeological aurochs depictions. It got better in my recent reconstructions, but I am still trying to figure out the accurate extent of soft tissue around the bones.

 

-) Ribcage not deep enough

 

The deep ribcage is an aurochs trait that is often overlooked, also in “breeding-back”. Most domestic cattle have a ribcage that is not nearly as deep as in the aurochs. I noticed that detail only a few years ago, hence some of my earlier reconstructions, and also some of the more recent ones, are incorrect in this respect.

 

-) Legs far too thin  

 

This is related to “shrink-wrapping”, but sometimes it happens that the legs of my reconstructions are so thin that not even the bones would fit into them. This is the case in my recent reconstruction of the Cambridge skeleton (go here). I have to pay more attention to that.

 

-) Underestimating the size of the horn sheaths

 

To be fair, there is no rule for how much keratin to add to a bovine horn. The solid part of preserved aurochs horn sheaths varies from 5 cm to 33 cm. So there is some room for artistic license. But in my older reconstructions I definitely underestimated the length that the sheath adds, and sometimes the horns I reconstruct might still be a bit too thin.

 

-) Ears too small

 

The skeleton provides no clues as to how large the ears were in life. Maybe the ears of the aurochs were as large relatively as in domestic cattle, although cave paintings show rather small ears. If domestic cattle are the standard, often the ears of my reconstructions are too small.

 

One reconstruction (or more accurately, an illustration, I did not track out the original bones for this one) that is devoid of these mistakes might be this one I did of the Önnarp aurochs:

 

Part of the reasons why these inaccuracies happen to my reconstructions is that not every aspect of the aurochs’ life appearance is known with certainty. Part of it consists of guesswork, but some guesses are better than others. But for the sake of completeness, here are some of the unknown/uncertain aspects of the life appearance of the bovine:

 

-) S-shaped spine or straight lumbar spine?

 

Looking at living wild bovines, I tend to assume that the lumbar spine of the aurochs was straight and horizontal. However, all ancient aurochs depictions show an S-curved back. I have been reconstructing aurochs with a straight lumbar spine for a decade now, but I think I’ll go with the S-curved back for the next couple of reconstructions because that trait is so consistent in ancient depictions.

 

-) How long was the dewlap?

European aurochs seem to have had a short dewlap, unlike indicine cattle or the kouprey. However, how short was it exactly? Some less-derived taurine cattle breeds have a very short dewlap with almost none in the throat area, and this kind of dewlap is depicted in ancient artistic depictions, so I go with that.

 

-) How bulky was the trunk at which stage of life?

 

This is very tricky to me as the skeleton does not really provide a clue on that. Wild bovines do vary greatly regarding the correlation of the depth of the ribcage and the bulk of the trunk in life – wisents have a deep ribcage but often a slender waist, as one would expect from the skeleton, but gaurs are much bulkier, particularly the bulls, while their ribcage is surprisingly not very deep. Domestic cattle are not a reliable analogue either, because domestication affected their morphology greatly. Ancient depictions suggest a bulkier trunk, with the exception of the bull depiction at Siga Verde, which shows a rather slim waist.

 

-) How prominent was the hump?

 

The answer to this question depends on how much the surrounding soft tissue obscured the hump and how developed the M. trapezius was. Regarding this muscle, there is quite some variation among domestic cattle, even within Lidia. Banteng and gaurs are not a good analogue for this question, as their trapezius is less developed because combat behaviour is not as common in these species as in Bos taurus.

 

-) Was the aurochs shredded like the gaur and some Lidia?

 

Gaurs do look like bovine bodybuilders. Their muscles are well-developed and defined. Some Lidia bulls come close to this. In most wild bovine species, however, this is not the case. But the bones of the aurochs suggest that it was quite muscular because the muscle scars and attachments are very pronounced.

 

These are all of the most important flaws and inaccuracies in my aurochs reconstructions I can think of at the moment. If you know some that have not been mentioned here, feel free to point me to them.

 

The Prejlerup bull with gaur as a template

We do have a rough idea of how the postcranial morphology of the aurochs looked like in life, but the fact that soft tissue is not preserved gives room for quite some speculation. What the result of the reconstruction looks like also depends on what animals you use as a template for the reconstruction. I tend to avoid highly domesticated breeds for my reconstructions, because domestication has a dramatic impact on the morphology of cattle. If I use domestics as a template, it usually is Lidia, Corriente or feral cattle that I use.

 

But this time I wanted to pretend that the aurochs does not have living descendants and took a more or less distant (the aurochs does not have really close relatives among living wild bovines) relative among wild species as a template, the gaur. I wanted to reconstruct the Prejlerup bull, which is not only the largest more or less complete skeleton of the aurochs that we currently have, but also the bull with the coolest morphology. The massive skeleton with the well-developed muscle attachments suggests to me that this specimen at least was very muscular, quite like a gaur. So I looked not only at cave paintings and other artistic depictions of aurochs but also at the morphology of living gaurs. The basis for the reconstruction is this photo of the Prejlerup skeleton that my friend Markus Bühler sent me:

 

The skeleton is mounted rather accurately, only the hindlegs might be bent to much. Other than that, it is a very nice mount.

Looking at depictions from Dorogne, Lascaux and Chauvet and living gaur bulls, this is the result of my reconstruction:

 

I think it looks plausible and is not even very different from reconstructions where I used less-derived domestic cattle as a template.

 

My next couple of reconstructions will be another experiment: I will reconstruct them as if there were absolutely no living relatives of the aurochs, with only the skeletons and the contemporaneous artistic depictions as a guide.

 

Portrait of the Vig bull

Recently I did a little portrait of the Vig bull, one of the two famous Danish aurochs specimen (the other one being the Prejlerup bull). I started it by tracking out a photo of the skeleton and reconstructing the tissue around it, then redrawing my sketch onto a canvas. The actual painting was done in acrylics. 

The Vig bull is from the early Holocene of Denmark, when forests started to become more prevalent after the mass extinction of Megafauna back in the late Pleistocene, so I chose a forest edge as a background. 

The result can be seen on my new Instagram account (go here). Consider following me there, I will upload most of my new aurochs artworks there. 

I am quite happy with the result, it also matches the Lascaux bull paintings very well, I think.  

Why dividing the mainland aurochs into subspecies might be outdated

It has long been established that the aurochs can be divided into several mainland subspecies: B. p. namadicus, the Indian (South-Asian) one, B. p. mauretanicus (African), B. p. primigenius (European) and B. p. suxianensis (East-Asian). I was not entirely happy with this taxonomy, as it is clear that they are not distinct, isolated clades but have a continuous range and the morphological differences between them are more like tendencies (such as that East-Asian ones tend to have a convex snout but these are not exclusive to them etc.) rather than clear autapomorphies. Recent genetic analyses suggest that the idea of mainland aurochs subspecies tied to certain regions is not tenable and that the evolutionary history of the aurochs was much more complex than what a taxonomy with four mainland subspecies would suggest. The island subspecies, however, are – at least in my opinion – a different story as they were clearly reproductively isolated for at least a certain amount of time. Two studies are of particular relevance for the phylogeny of wild Bos primigenius (or Bos taurus, depends on what you prefer).

 

Rossi et al., 2024: The genomic natural history of the aurochs.

38 aurochs genomes from the Late Pleistocene to Holocene were analyzed. The lines of taurine and indicine cattle diverged around 166-300kya. Taurine-line aurochs and indicine-line aurochs descend from a common population that lived around 390kya. Within the taurine-line aurochs, North Asian aurochs separated from Southwest-Asian aurochs after 100kya, splitting from a common ancestral population. More archaic aurochs, however, left a minor trace in those later taurine-line aurochs. The North-Asian aurochs haplogroups C and K split from the other taurine-line haplogroups P, Q, T, E and R around 96 to 72 kya.

 

Zhu et al., 2025: Revisiting aurochs haplogroup C: Paleogenomic perspectives from Northeastern China.

It covers all the mitochondrial haplogroups P, T, E, Q, R, G, K, C, I and shows a phylogenetic cladogram. The Central Asian haplogroup G is the basalmost one, basal to the group taurine + indicine line and separated around 400kya. R, so far found in North African aurochs, is closer to a clade of K and C from Asia than to T or P.

 

What is surprising to me is that the split between the taurine-line aurochs and indicine-line aurochs is that recent. This means that most namadicus fossils, which are from the Middle Pleistocene to the early late Pleistocene, cannot be considered ancestors of the zebu any more than other archaic aurochs from that time. It also means that the 700.000 year old Wadi Sarrat skull from Tunisia does not belong to the same line as late North African aurochs but is much more basal.

Looking at the phylogeny of the various aurochs haplogroups and comparing it to their location it becomes clear that the aurochs genomic history is much more complicated than a subdivision into four mainland subspecies would suggest. As Rossi et al. and Zhu et al. note, the range of the aurochs likely expanded and contracted with the countless climate oscillations during its existence, and looking at the relationship between R (North African) and K/C (Asia), clearly a lot of migration must have been involved.

I think that, based on the phylogeny of the various aurochs lineages, it is not useful to subdivide the mainland populations into subspecies. Especially as the type specimens for the respective subspecies taxa are not publicized (with the exception of B. p. primigenius, the Haßleben aurochs), which would be necessary to see which taxon equates to which genetic lineage. Apart from that, it would be of limited use to erect a subspecies taxon for each haplotype or genetic lineage given the diversity found within the aurochs. And we only know about half of the diversity found within the species, given that we do not have genomes from earlier aurochs. So now we know that there were non-crown-group aurochs in the late Pleistocene, that the split between indicine-line aurochs and taurine-line aurochs occurred fairly recently.

 

 

 

My book now available as an ebook

Due to the many request for an ebook, I now made a kindle ebook version of my book. The advantage is that it is way cheaper since there are no printing costs. If I had known how many want an ebook, I had made one from the start - I apologize. 

 

 Go here for the kindle ebook. 

Auerrind individuals joined the Fahrendahl Heck/Taurus herd!

Earlier this year, the Heck/Taurus herd at Fahrendahl (https://www.auerochsen-fahrendahl.de/) was joined by three individuals from the Auerrind project: Costanza (the Chianina x Watussi cow), Henry (a son of Claus and Doro) plus a young cross cow. Now new breeding herds have been assembled: 

The video shows one of the new breeding groups with the sire Ernie (not to be confused with Erni, the Steinberg/Wörth cow), who has Taurus influence and is estimated to be 150cm tall at the withers. Ernie's herd not only has Constanza in it, but also the extremely beautiful Taurus cow Eliese from the Lippeaue (a daughter of Laniel and a daughter of Londo and Lerida). 

 Another breeding herd this year is that of Elias - a son of Eliese and Egon (a Steinberg/Wörth-influenced Heck bull) with a top ancestry and great potential (and quite an aesthetic look, I think). 

The third breeding herd is with the bull Kasimir, a son of Dominator and Bionade! He is joined by Ella, a daughter of Egon and Eliese. What I love about this young cow is that the Chianina influence is recognizable yet it still has the dense and shaggy Heck cattle winter coat (you can see it here f.e.). They share the herd with some beautiful classical Heck cattle cows. 

 

I am amazed by these great animals and the potential of these combinations is tremendous. The Fahrendahl herds are definitely among the most promising breeding-back herds today.  

 

The African aurochs was even more different than usually assumed

I did a couple of posts on the fur colour of the African aurochs in the past, and all of them are more or less outdated. Yes, aurochs in Africa seem to have had a light colour saddle, but their colour was much more deviant than usually assumed.

 

It all depends on the nature of the bovines depicted in Egyptian tomb paintings. Van Vuure (2005) assumes those are all feral domestic cattle because of the horn shape depicted, but there are some that clearly show aurochs. One of them is the so-called “ostracon with fighting bulls”, which can be found on the internet. This inspired me to my painting of an aurochs bull with exactly that colour fighting off a lion in the Nile delta, which can be seen on my Instagram page.

 

But there are a number of depictions that suggest that there were even more deviant colour variants found in the North African aurochs populations. Looking at all of them, I did this reconstruction based on a skull at the Oran caves:

 

A list of tomb paintings suggesting this colour as much as what the genetic background of it might be can be found in my recently published book.

 

 

A sneak peek into my book

Today I want to give you a little sneak peek into my book so that you can see what you can expect from my book "Breeding-back wild beasts: aurochs, wild horse and quagga". Now available on Amazon. 

Life reconstructions, anatomical drawings of all types of aurochs 

 

Lots and lots of photos of "breeding-back" cattle, including brand new previously unreleased photos of the Hortobagyi animals

Previously unpublished reconstructions of wild horses

Reconstructions showing the variation within the quagga

The cover; I'll reveal the bull on the cover in an upcoming post

My book is available on Amazon!

Today is a great day for me. My book Breeding-back wild beasts: aurochs, wild horse and quagga is published and available on Amazon!

 

Go here for my book on Amazon

 

With this book, I turned all the material I gathered on this blog in 12 years into one comprehensive work, but I also included new studies that I haven’t covered on this blog yet. The bulk of the work is on the aurochs, but of course it also has a chapter on wild horses with a lot of material, and also a chapter on the quagga. And of course also a chapter on dedomestication, which is also relevant for “breeding-back”.

The book has more than 150 images, most of which are photos and life restorations I haven’t published previously.

 

These are the contents:

 

- In the first section, I cover the debate of the influence of megafauna on the landscape

- The phylogeny, taxonomy, behaviour, ecology and morphology of the aurochs is covered, the latter very extensively as you can imagine

- The domestication of the aurochs is outlined, including remarks on the mechanisms of domestication in general, including the domestication syndrome

- The history of breeding back is outlined, the role of genetics in breeding back is discussed

- A section on the history and various breeding lines of Heck cattle with lots of photos

- A section on Taurus cattle in Germany and Hungary with lots of photos, including never-before published new photos of Hungarian Taurus cattle

- A section on Tauros cattle with lots of photos

- A section on Auerrind cattle with lots of photos 

- A chapter of sections discussing hybridization with wild bovines in breeding back, the challenges for breeding back, new breeding strategies based on genetics et cetera

- The taxonomy of wild horses with remarks on the status of the Przewalski’s horse

- An extensive section on the quest for the morphology and appearance of western Eurasian wild horses and its alleged subtypes

- A section on the origins of the Exmoor pony, the Konik and the Sorraia

- Thoughts for a “breeding-back” project with horses, covering the Lippeaue horses

- A chapter on the phylogeny, morphology and appearance of the quagga and of course also the Quagga Project

- A chapter explaining my dedomestication hypothesis focusing on cattle, covering the Heck cattle at Oostvaardersplassen and Chillingham cattle, the latter with lots of photos

- Final remarks

 

The book is of course in colour and printed on qualitative paper so you can enjoy the lots and lots of photos and artworks.

 

As you know, I put my heart blood in this book and I am confident that readers of my blog and all other enthusiasts for these extinct animals will enjoy it very much.  

 

Another archaic aurochs: the Wadi Sarrat skull

A while ago, I posted a reconstruction I did of an archaic aurochs from India. This time, I did a little sculpture of an aurochs that was even older, the Wadi Sarrat skull. It was published in 2015, found in Tunisia and is roughly 770.000 years old. The skull is only partially preserved, but with complete horn cores that have astonishing dimensions. The horns face forward in a 40° angle. No postcranial material has been recovered as far as I know.

 

I reconstructed the body based on the Store-damme skeleton and the head and horns precisely after photos of the Wadi Sarrat skull. For the colouration, I was inspired by a colour found in many wildtype-coloured zebu: black base colour with a dorsal stripe, light areas on the ventral body and brownish flanks. There is no evidence for the colour of aurochs that old, and since the Wadi Sarrat skull is outside the modern aurochs crown group, we have a bit of artistic license for the colour. Here is the sculpture:

 

If the bull the Wadi Sarrat skull belonged to was proportioned like that, it would have been 160cm tall at the withers.