"Breeding-back" aims to restore or immitate extinct animals by selective breeding. This blog provides general information, the facts behind myths and news from various projects.

Tuesday, 29 July 2025
My book now available as an ebook
Friday, 18 July 2025
Auerrind individuals joined the Fahrendahl Heck/Taurus herd!
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).
Sunday, 13 July 2025
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I did a couple of posts on the fur colour of the African aurochs in the past, and all of them are more or less outdated.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.
Wednesday, 25 June 2025
A sneak peek into my book
![]() |
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Previously unpublished reconstructions of wild horses |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 |
Thursday, 19 June 2025
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!
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.
Saturday, 14 June 2025
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.
Saturday, 31 May 2025
My new project: life-sized aurochs head bust
During the past few weeks, I have been busy with finalizing my book (which will be out soon) and also starting a new sculpture. This time it is not a small full-body sculpture but a life-sized aurochs head bust. It is based on the Ilford skull at the British Museum of London. I thought it would be most precise to at first replicate the skull as accurately as possible and then to reconstruct the soft tissue and fur around it. This is the replica of the skull, made of paper maché, fimo air and polyurethane foam, photo taken today:
It looks a bit slenderer than the Ilford skull, which is only on the photo. Perhaps due to perspective. A 3D-scan of the actual skull was very helpful to me for getting the proportions right. My replica is exactly 73,5 cm long, which is the size of the Ilford skull that I was told.
It was quite difficult to get the horns right, due to their highly three-dimensional curvature.
The next step will be connecting the lower jaw to the skull and then creating the base of the neck with the foam. Then I am going to sculpt the horn sheaths over the cores, which always involves some speculation as there is no rule of thumb of how much the sheath adds to the length of the horn. The final surface of the bust will be made of fimo air and I am going to paint it with acrylics.
Saturday, 12 April 2025
Was the European aurochs woolly and shaggy like Highland cattle?
Thinking about the coat of the European aurochs, there is a notion from Conrad Gesner, who owned a piece of an aurochs skin, describing the coat as it follows:
“… the hairs are really very soft (surprisingly so), like the wool of sheep, close together…” (cited from van Vuure, 2005)
For quite a long time, I did not know what to make of that notion. My assumption was that the coat preserved on the skin was dismembering and that the longer outer coat had been fallen off, revealing the finer hair of the undercoat. While this is possible, there is also a quote from Anton Schneeberger, describing the aurochs of Jaktorow:
“They look a lot like domestic cattle, but are much larger and covered in longer hairs…” (cited from van Vuure, 2005)
He notes that aurochs were covered in longer hair than domestic cattle. This raises two questions: was he referring to the coat in general or just the winter coat? Which domestic cattle was he thinking of when comparing the aurochs against them? Since Schneeberger’s report is rather precise and he makes a special notion on the coat being shinier during autumn but not that the hair was only longer than in domestic cattle during winter, it could be possible that he was referring to the hair in general. Since he was German, he was probably comparing them against rural Central European breeds and not short-haired Southern European or even African breeds.
There is a third reference on the hair of the aurochs (by Baron Bonar):
“When the skin of this animal has been cleaned it is covered in very fine black hairs” (cited from van Vuure, 2005)
So we have two historic notions stating aurochs had very fine hair and one that these were longer than in domestic cattle. The notion that the coat was woolly is curious, as most cattle on this world have rather coarse hair. However, woolly long hairs remind of breeds such as Highland cattle and Galloways. Could it be possible that aurochs had a coat like those breeds?
Another detail of the coat of the aurochs is interesting, namely the curly hair on the forehead. We have two independent documents describing this trait in aurochs: Schneeberger and Swiecicky. Curly hair on the forehead is rather widespread among cattle, so it is surprising that the authors mentioned them specifically as a special trait of the aurochs. Schneeberger even stated that they make them “terrible to behold” and Swiecicky described the hair on the forehead as shaggy and mentioned that there was even an idiosyncratic name for that trait of the animal in Polish. This suggests that the curly and shaggy hair between the horns was more prominent in the aurochs than in domestic cattle, which fits the notion that they were covered in longer hair than cattle. Shaggy forehead hair again reminds of Highland cattle.
Would a Highland cattle coat have been functional for the aurochs? Given that it makes the breed extremely cold-tolerant one might think so, since Europe was, together with Northern China, the coldest part of the range of the species. However, their long coats can make the animals suffer heat stress above 30°C, which is why they often take a bath during summer to cool down. There have been cases where Highland cattle drowned in the mud because of that. This is not advantageous in the wild, which makes it unlikely to be the wildtype condition. Also, the forehead hair of Highland cattle is often so long and shaggy that they cover parts of the eyes, which would impede the sight of the animals and thus is not advantageous as well. But there are also Highland cattle in which the summer coat is much shorter than during winter. They then also have the very fine almost woolly hair. See this bull for example. I assume the heat stress with this kind of coat would be much less than when the hair is long all the year round.
Other British landraces such as English Park cattle, English Longhorn, Dexter cattle and Chillingham cattle also have a coat that looks comparably woolly by cattle standards, although shorter. The coat of Galloways ranges from very similar to that of Highland cattle to very similar to that of Park cattle. British landraces have been found to have been influenced by British or Northwestern European aurochs, so they might have their coat directly from aurochs of the Northern half of Europe. Cattle from other regions of the world usually do not have that coat, except for some Turano-Mongolian cattle such as Yakutian cattle. They have the same woolly, almost fluffy, coat and are known for their adaptions to very cold climate. Yakutian cattle are not particularly close related to British landraces as Turano-Mongolian cattle were quite isolated from European cattle breeds, but they might or might not have been influenced by local aurochs in Asia. I say this because the genetic evidence we have today makes it very likely that aurochs and cattle interbred everywhere they met, which does not make them any different from other species that were domesticated.
So, what does this tell us about the European aurochs’ coat? Without having any skins preserved, we cannot be sure how long, soft and woolly its coat was, and to which extent the winter coat and summer coat differed. But intuitively I think the coat might have been somewhat intermediary between that of Highland cattle and Chillingham cattle. I think so because the notion that the aurochs was covered in longer hair than domestic cattle was the second aspect of the aurochs’ appearance of all that Schneeberger mentioned, so that this might have been quite a prominent one. I have been speculating for quite a while that aurochs bulls might have had the curly mane that Chillingham cattle have (see the post “Forelocks and manes”). Its function might be protection from the horns during combat and is found in many taurine cattle bulls. Interestingly, it is also found in some Heck bulls in the Oostvaardersplassen reserve, but rarely outside the reserve. As for the hair between the horns, I think some Highland cattle with curly hair between the horns might be a good model for those of the aurochs, because they must have been prominent enough to be mentioned in several independent sources and to be called “shaggy”, which would suggest that the hair was longer than in Chillingham cattle at least between the horns.
Should this have implications for “breeding-back”? Maybe, maybe not. First of all, we don’t know how widespread that kind of fur was among the aurochs and I think it is quite likely that aurochs with a more southerly presence had the same coat we see in most taurine cattle. But if the cattle are to be as precise of a phenotypic copy of Northern/Central European aurochs, the use of Highland cattle might advantageous and I would like Chillingham cattle to be used in “breeding-back” in general. Yakutian cattle would also be fantastic, but probably difficult to acquire. Heck cattle and Tauros cattle have Highland cattle in their ancestry, so there might be potential in achieving the coat described by Schneeberger. At least in Tauros cattle, as the crossing-in of Highland cattle has been rather recently while it has been 100 years in Heck cattle. On the other hand, so far, breeding-back cattle have done fine under natural conditions with the coat they have. And perhaps it would be best to create a genetically diverse aurochs-like population with many different alleles for coat phenotypes and let natural selection do the rest.
Interesting in this regard are the feral cattle on Sanak island. They descend mainly from Highland cattle, but were exposed to natural selection. Despite the climate on the island, they are not quite as shaggy and long-haired as usual Highland cattle. Perhaps natural selection has reduced the hair length to the maximum that is functional in the given climate. This might make the Sanak island cattle a possible model for the coat of the aurochs, just like Chillingham cattle and OVP Heck cattle.
I did a reconstruction of an aurochs based on a skull found in Lake District in England with a coat that I can imagine as one of the plausible possibilities of a more shaggy aurochs during summer. The coat could have been longer or shorter too, without a preserved skin we cannot know for sure, unfortunately.
Thursday, 27 February 2025
How to rescue Bos taurus taxonomically
Thursday, 16 January 2025
The weird proto-aurochs from the Pleistocene of India
I actually wanted to include this in my upcoming book – which will be published soon – but it turned out to be too speculative for my taste. It is about this skull from the Middle Pleistocene of India:
Copyright holder unknown - if you are the copyright owner and would like me to remove that photo, please let me know.
As you can see, the horns are very wide-ranging, but unfortunately not preserved completely. In order to get a more complete picture of what the horns might have looked like in life, I sculpted a little head bust in trophy-style to reconstruct the horns three-dimensionally.
I only know a couple of photos of this skull, of which none are in a clear profile shot, but I was able to replicate the horn cores rather exactly based on the photos. Then I sculpted the horn sheaths over them. This is the result:
While the actual morphology of the head and horns is based on osteological evidence, the colour is entirely speculative. As these Middle Pleistocene aurochs are very likely outside the taurine + indicine clade, I played a bit with my fantasy regarding the colour. It could well be possible that it had the “standard” aurochs colour, especially considering the fact that Java banteng have an almost identical colour to the “standard” colour.
All in all, based on what I have seen from Bos acutifrons so far, I think the idea that there was a morphological continuum from acutifrons to namadicus to primigenius is not far-fetched. Interestingly, the earliest record of aurochs is currently from Tunisia. In the Early Pleistocene in Africa, there was another species of catte that had, just like acutifrons, large and very wide-ranging horns as well, Bos buiaensis. I think it is not entirely impossible that acutifrons and buiaensis were conspecific and ranged across two continents (just like primigenius) and gave rise to the aurochs. But without any genetic information, which would also be needed from Leptobos, Epileptobos and Pelorovis, it is impossible to resolve the exact origins of the aurochs – at least currently.
So, was namadicus a distinct species, Bos namadicus, or a subspecies of Bos primigenius? This question is, in the lack of a clear species definition, impossible to answer and thus is up to the author’s preference. Another problem is that since species evolve gradually, that “transitional forms” and “real species” are just arbitrary categories based on the time we live in, which we choose as an arbitrary anchor. If species A evolves into species B, and species B into C, the transitional species between B and C would be regarded as a “true” species for its time, and would relate to the transitional species from A to B like a “true” species, making A, B, and C merely “transitional” forms. We can expand that problem even further. Species A and C, if they would for some reason meet each other, might not be able to reproduce with each other, but the species B can reproduce with both of them, making A, B and C one ring species across time. We could trace that back to the very ancestors of all life. The species concept does not work across time, I think. Just some thoughts.