How aggressive was the aurochs?

As my readers will know, many of my blog posts on the aurochs focus on aspects of its morphology or appearance, because that is what we know most about. But I also made posts covering social behaviour patterns, like this one. Today I want to cover a behavioural aspect of the aurochs that I am sometimes asked about: its aggressiveness. More precisely, its aggressiveness towards humans. Was the aurochs an aggressive animal towards humans, or was it gentle and docile? 

Regarding the aggression of the animal, we have to differentiate between intraspecific aggression, aggression towards other animals (predators in particular), and aggression towards humans. That is important because domestication drastically changed the latter factor, while the other two factors seem to be somewhat independent from it. Cattle that are very agreeable and docile towards humans still can become rather aggressive against opponents in intraspecific combat or towards possible predators. The question how aggressive the aurochs was is also important for “breeding-back” as it raises the question what kind of behaviour the cattle need in order to survive in nature, or to be aurochs-like, and what to expect from dedomesticated cattle living in the wild. 

 

Historic evidence on the behaviour of the aurochs towards people

 

The most famous notion on the behaviour of the aurochs is in Caesar’s Commentarii de bello gallico, writing that aurochs “will spare neither humans nor animals at sight”. Caesar also wrote that aurochs never get used to humans, even if raised as calves. Also, Anton Schneeberger who visited the last Polish aurochs in Jaktorow wrote that aurochs will get very hot-tempered when challenged. Andrea Swiecicki reported from the 16^th century that aurochs will get very aggressive when being tormented and attack humans and horses, throwing them in the air with their horns [1]. Schneeberger further writes that aurochs are not afraid of people and will not run away if they stand in the way of the humans. As the Jaktorow herd was managed by humans and encountered people on a regular basis, it is possible that they were tamed to some degree [1]. These are the only general notions on the behaviour of aurochs towards people that have been preserved, at least as far as I know.

Caesar’s notion can be interpreted in a way that aurochs were generally aggressive animals, but Schneeberger’s and Swiecicki’s seem to be more differentiated, stating that they can become very aggressive when challenged or being hunted. Caesar’s impression that the aurochs will not spare any living being might come from the behaviour of the bovine in situations of threat. If one knows the animal only in the context of hunting it, one might assume it is generally a very dangerous animal. Schneeberger’s report clearly states that aurochs would not attack without a reason whenever they encounter a human, in fact he writes that one could easily approach it. If the aurochs at Jaktorow were indeed tamed to some degree, this could imply that the behaviour of aurochs towards humans was plastic and partly depended on socialization. However, Caesar’s notion that they never get used to humans even when raised as calves indicates that there were genetic limits to this. This is likely, as the difference in behaviour between domestic and wild animals is due to genetic differences to a certain degree. Curiously, Vergilius mentions that in the Po River area in Northern Italy aurochs were caught and tamed to be used as draft animals, in the lack of domestic oxen [1]. Either it was indeed possible to use grown, wild-caught aurochs for draft work or Vergilius was misinformed. It is even possible that these animals were not aurochs but feral cattle living in the region. Personally, I cannot imagine that it would be possible to use an undomesticated wild bovine for draft work, even if they were tamed to some degree. I think Caesar’s notion is more credible than that of Vergilius, both authors were basing themselves on second-hand information. 

 

The behaviour of domestic cattle 

 

For the social behaviour of the aurochs, cattle living under natural circumstances are a pretty good model. What we know of the social behaviour of the aurochs is congruent with that of cattle, and since domestication likely did not affect the social behaviour patterns of cattle, all the other aspects of their social behaviour are likely shared between aurochs and domestic cattle. One difference is, however, that cattle tend to mate all year round while the reproductive circle of the aurochs was adapted to that of the seasons, with a mating season during fall and the birth of the calves in spring. 

But that domestic cattle are a model for the aggression level of the aurochs is very unlikely. First of all, domestication likely drastically changed the hormonal system of cattle, particularly the corticosteroid hormones, what has an influence on the aggression and stress response of the animals. Furthermore, there are considerable differences between breeds in their behaviour towards humans. Highly derived breeds in particular are very agreeable, docile and have a very minor stress response. In some breeds the bulls can even be ridden. The Spanish fighting bull, on the other hand, is the complete opposite. Lidia have a very intense stress response and attack readily, although there is individual variation in “fighting spirit” within the breed. Most domestic breeds were artificially selected for agreeableness and less intense stress response, Lidia was artificially selected for an intense stress response, so that it may be the case that neither of them is a model for the behaviour of the aurochs towards humans. 

The potential for aggression, particularly towards humans, must have a genetic component otherwise it would not be heritable. The MAO-A gene seems to be different in Lidia compared to other taurine cattle breeds (go here). This gene plays a role in the endocrinology in the brain of mammals, and mutations on this gene are linked to increased aggression in other species, suggesting that this plays a role in the aggression of Spanish fighting cattle. It would be interesting to have a look at this gene in the aurochs. Since the full genome of the aurochs has been resolved, this should be possible. The MAO-A gene is probably one of many genes that influence the potential for aggression in cattle. 

 

To sum it up, aurochs likely would have had the potential to become very aggressive and energetic when defending itself, like other wild bovines. We do not know, however, how readily wild aurochs would have attacked if they encountered a human being that they consider threatening to them. Some aspects, like flight distance, might have partially depended on socialization. However, as Caesar writes, an individual raised under human custody likely would never lose its wild nature as they were undomesticated animals. 

 

All current “breeding-back” projects select against aggressive behaviour towards humans, which is understandable as they have to work with the cattle as the law dictates. As long as the animals have to be handled, it is better for the cattle and the people handling them that they do not have an extreme stress response. As we do not precisely know how aggressive aurochs were, I think it would be most sensible to let “rewilded” cattle develop their own aggression level that is formed by natural selection and thus what is best for them in order to survive in nature.

 

[1] van Vuure, 2005: Retracing the aurochs: history, morphology and ecology of an extinct wild ox. 

 

 

 

Reconstruction of a complete Indian aurochs skull

The Indian aurochs, Bos primigenius namadicus, is enigmatic compared to the European subspecies. Not a single complete skeleton has been found yet, and I have not seen a complete cranium either. I wanted to get an idea how the complete skull of that subspecies might have looked like, so I tracked out the namadicus skull presented in [1] (which might or might not be the same skull that is on display at the Geological Survey of India) on paper and reconstructed the complete skull using the fragmentary cranium. 

 

The trickiest part was to estimate how long the snout would have been. I suspect that the skull broke off right before where the nasal bone and the premaxillary bone touch each other, and that the toothless part of the upper jaw is roughly the same length in lateral view as the toothed part. The lower jaw is based on those of European skulls. This is the result:

I think the result is very plausible, it does not look proportionally weird concerning the snout length. It also looks credible for a type of aurochs that was the predecessor of indicine cattle. For comparison, here is a zebu skull. 

 

As no postcranial material that is worth mentioning has been published so far, I cannot do this with a complete skeleton, unfortunately. However, I think there must be enough fragmentary postcranial material of that subspecies to make a composite skeleton, so that it is possible to get an idea what the morphology of namadicus was like. A rigorous description of the postcranial skeleton of the Indian aurochs is lacking so far. 

 

[1] Gregoire Metairs: Evolutionary history of the large herbivores of South and Southeast Asia (Indomayalan Realm).2016. 

 

Video of fully grown Lidia bulls

Most Lidia bulls we see are young bulls at the age of three or four, because that is when they have their full body size but are comparably slender and most athletic. After that age, they become heavier, as all bulls do. It is rare that fully grown Lidia bulls are presented on the media as they are not as athletic and swift than young bulls. But here is a video of Lidia bulls that are most likely fully grown:

They are still pretty muscular, as typical for the breed, but heavier than their younger counterparts. What is most interesting to me is that a number of individuals have much more aurochs-like horns than young bulls. At the age of three, the horns are not yet fully developed and can change quite noticeably. Many young Lidia bulls have a somewhat two-dimensional horn curvature, while some of the bulls in this video have a nice primigenius spiral, in particular the bull at 5:07 and the one at 9:34. I think that supports the idea that the horns of Lidia are more often aurochs-like than what the young bulls seem to suggest, if they only get the opportunity to grow to full adulthood their horns will be more developed and that can result in a primigenius spiral. 

A plea for more Maronesa in "breeding-back"

Maronesa is an awesome breed that I always enjoy looking at. Like all aurochs-like breeds, they have their pros and con’s. To sum them up: 

Con’s: 

- small or at least not large body size 

- short skull shape 

- bulls can get rather short-legged and heavy 

Pros: 

- the coat colour is absolutely identical to that of the European aurochs 

- the sexual dichromatism is nearly always present and well-marked, identical to that of the European aurochs 

- the horns can face inwards in a very aurochs-like manner 

 

Although the number of pros and con’s that come to my mind is the same, I think the benefits of that breed outweigh the undesired traits. That is, for once, because it is very, very rare that a cattle breed has a colour that is truly identical to that of the European aurochs – actually the only other European breed that I know of is the old lineage of Corsican cattle, which is critically endangered if not has already disappeared. It’s impressing to imagine that during roughly 10.000 years of domestication, not a single domestic colour mutation has found its way into the Maronesa genome. But even more important is the fact that the sexual dichromatism is nearly always present and as well-marked as in the European aurochs, because sexual dichromatism is a complex trait that is very difficult to breed for in domestic cattle. I did a post on that, coming to the conclusion that the only way to achieve an authentic dichromatism in “breeding-back” is to rely on a breed that already has it to the desired extent. That would be Maronesa. At least I know of no other breed that has an authentic dichromatism except for the old lineage of Corsican cattle. Also, the horn curvature of some Maronesa is very useful as the horns curve very strongly inwards in an aurochs-like manner. This is very rare even among aurochs-like cattle. Just look at this cow. Overall it has great potential for aurochs-like offspring. The colour is perfectly identical to that of the aurochs, the horns curve inwards in an aurochs-like manner and it has a perfect dichromatism (I assume so because it is the rule in the breed and there are no lightly coloured Maronesa bulls). 

 

Considering the potential of the breed, I think it is dramatically underused in “breeding-back”. The only current project that is using Maronesa is the TaurOs Programme. That is problematic because they use only a small number of Maronesa individuals, they do not execute selective breeding but let the cattle breed for themselves instead, they crossbred them with breeds that are not really beneficial from the perspective of aurochs-likeness (f.e. Maremmana) and the results are modest. And that is although the project would badly need good Maronesa to improve the horn shape of their cattle, as the horns of most TaurOs cattle face outwards, and the sexual dichromatism which is completely absent in some herds (f.e. Milovice). I would highly recommend the Tauros Programme to try to achieve another herd of Maronesa from Portugal, this time better individuals (that have truly inwards-curving horns and a good morphology etc.), also including grown bulls, as bulls have a greater influence on the herds than single cows. 

Also, Maronesa could be beneficial for the Auerrind project in the future. That would depend on how good the dichromatism is going to get with the set of breeds currently used – Maremmana, Sayaguesa, Watussi and Grey cattle have a rather reduced dichromatism, Pajuna can be good in this respect, and in Chianina a dichromatism is possible but masked beneath their colour dilution if present. If it turns out in the future that Auerrind crosses do not have a well-marked dichromatism and inwards-facing horns, including good Maronesa could be beneficial. But as for now it is too early to judge that, as the second-generation crossbreeds are not fully grown yet. 

Maronesa would even be an option for Heck cattle breeders to increase the aurochs-likeness of their cattle. Some Heck cattle breeders don’t like large individuals, or simply like the looks of Heck cattle regardless of their aurochs-likeness. Maronesa would improve the horn shape and sexual dichromatism without altering the looks and body size of Heck cattle dramatically. But Heck cattle would not be my first choice to crossbreed good Maronesa with, to be honest. 

Would TaurUs cattle benefit from Maronesa? I am not sure about that. Many Taurus cattle in the Lippeaue already have inwards-facing horns, and the sexual dichromatism is good in the herds as well – I examined it for the year 2015 using a photo archive, and it turned out that more than 80% of the individuals have the “right” colour. Go here for the post. Apart from that, they have done a good job at creating truly large cattle, Maronesa might diminish that. As most of the achievable aurochs-like traits are already present in the Lippeaue, I do not think that Maronesa would be necessary or, considering their con’s, worth the effort in Taurus cattle. 

 

Another option to seize the potential of Maronesa would be conducting a new, heavily Maronesa-based breeding project. I would use Maronesa, Chianina and Watussi for such a project. Precisely, I would create a number of F2 Maronesa x Chianina, and F2 (Maronesa x Watussi) x Maronesa, and then create an F2 from the combination of both lineages. That would take five breeding generations, and thus roughly ten to 15 years, but the results could be quite qualitative. 

 

I think it would be a shame if Maronesa was not used on a larger scale in “breeding-back”. That is also because it seems that the aurochs-like less-derived Maronesa lineages are endangered. From what I have heard, the sexual dichromatism is not always appreciated by Maronesa breeders and there are already some almost black Maronesa cows. If that trend continues the breed might lose its dichromatism and end up looking like Sayaguesa in that respect. Also, some Maronesa are bred for an extremely massive body with a bulldog face, and many Maronesa cows have corkscrew-like horns (I do not know what is the preference of Maronesa breeders regarding horn shape). The less-derived type of all aurochs-like landraces is endangered because of crossbreeding with more economically productive breeds and/or selection towards a more derived appearance, and so is that of Maronesa, at least because of the latter factor. Thus I really hope that “breeding-back” will seize the potential of that breed, and that the less-derived aurochs-like representatives of Maronesa do not disappear without contributing noticeably to the “breeding-back” gene pool. 

 

The colour of the African aurochs

I did a post on the African aurochs a few years ago. In that post, I outline that it is likely that the bulls of this subspecies had a light colour saddle on their back, instead of being entirely black except for the dorsal stripe as the European aurochs evidently was. This is because at least three depictions of African aurochs bulls show this trait very clearly. This might not be the full story, however. 

 

Part of the reason why I am saying this is the ancient Egyptian aurochs depiction described in Beierkuhnlein 2015: 

from [1]

It shows an aurochs bull, a cow and a calf. It is somewhat stylized (see the horns), but rather detailed. It shows the white muzzle in the cow (the mouth of the bull and calf are not preserved), it shows either a rather broad dorsal stripe in the bull or a colour saddle (that is probably open to interpretation), a narrow dorsal stripe in the cow and a possible dorsal stripe in the calf similar to what is depicted in the bull. The colour of the bull seems to be a little bit darker than that of the cow, but still is brown. However, there is also a depiction of a dark brown aurochs bull from Europe that is also very stylized, and as I mentioned, the depiction is a bit stylized. So it’s still possible that the bull this artwork was based on was black. But what is most interesting to me is that the bull has light areas on the dewlap, belly and inner sides of the legs. Also the cow and the calf have a lightly coloured belly. 

When I first noticed that I did not really care about that because I thought the artwork is stylized anyway, so it could be artistic license. However, these light areas are a trait often seen in many zebus. In fact, I have not yet seen a male wildtype-coloured zebu without taurine influence that does not at least have lightly coloured “armpits”, often the light area extends to the dewlap and entire belly and the inner sides of the limbs. This Sahiwal bull shows this kind of colour: 

If these light areas were present in the Indian aurochs, which was the wildtype of the zebu, it might not be that far-fetched to assume their presence also in the African aurochs. This would be in agreement with this ancient artistic depiction. Regarding the width of the dorsal stripe, I think it is possible that the African aurochs had a broad dorsal stripe in the shoulder area while the European aurochs had a narrow one (about “two fingers wide” as Schneeberger reported). I have seen dorsal stripes that get rather broad in the shoulder area in one Heck bull, one Pajuna bull and one Maronesa bull. African aurochs likely influenced African taurine cattle, which left a mark in some Southern European breeds, so it is not impossible that a broad dorsal stripe is a legacy of African aurochs introgression. This is speculative, especially as it is not clear if the artist of the depiction intended to draw a broad dorsal stripe or a saddle. I am inclined to think the artist did not differentiate between both structures. 

I also found a depiction of a bull with a very similar or possibly the same colour. It’s from a mural in the tomb of Nefertari. It is clearly black, has light areas on the ventral side of the trunk and the inner area of the legs, and also has this either broad dorsal stripe or colour saddle (go here). I am pretty sure it shows a domestic bull because it is shown along other clearly domestic bovines based on their colour (go here). But it could be a hint that this colour was found in the local aurochs type, as there likely was introgression from mauretanicus into North African taurine cattle. It could be a hint, but it certainly does not have to be. 

If the African aurochs had this lightly coloured area on the ventral side of the body plus a broad dorsal stripe, it might have looked like this: 

Personally, I find this colour scheme incredibly beautiful and also rather colourful and rich in contrast. But it is just as plausible that North African aurochs did not have these lightly coloured areas and were all black except for the saddle, dorsal stripe and muzzle ring. The evidence simply is not clear or plentiful enough to tell the exact colour of Bos primigenius mauretanicus. 

 

[1] Beierkuhnlein: Bos primigenius in ancient Egyptian art – historic evidence for the continuity of occurrence and ecology of an extinct key species. 2015. 

 

 

 

Horn size #2: aurochs with smaller horns

In the previous post, I presented a number of aurochs specimen with very large horns. This post is going to focus on the lower end of the horn size spectrum. Although the aurochs was a large-horned bovine in general, some individuals had surprisingly small horns – these small-horned aurochs are, however, not very numerous in the fossil and subfossil record, indicating that they were not common in the species either. 

 

-) The Prejlerup bull 

This skeleton is possibly the largest more or less complete aurochs skeleton that is on display, with a withers height of roughly 190 cm. Its horns, however, are not very large. They seem to be shorter than the length of the skull, what makes them “smaller” to me by aurochs standards. Surely the keratinous sheath would have added to the length, but the curvature shows that this would not have doubled the length of the horns, otherwise they would have crossed each other as the horns are not wide-ranging. 

 

-) The Önnarp skeleton 

This bull specimen has horns that are smaller than average for the aurochs. I know no measurements for the horn cores of that bull, unfortunately. Go here for the skeleton. 

 

-) The Himmelev bull 

Although the horns of the Himmelev bull are not tiny, they are quite a bit smaller than what is average for the aurochs. No measurments for the horn cores that I found. See here and here. 

 

-) The skull from Bauges 

In a cave in Bauges, France, a skull was found that has truly tiny horns by aurochs standards. No measurements for the horn cores of this skull are given, but there can be no question that they are significantly shorter than the craniocaudal length of the skull. Those are the shortest horn cores I have ever seen in an aurochs skull. The skull can be seen in this video. 

 

Still shot from the video linked above

-) The last Jaktorow bull 

We know exactly how long the horns of the last bull from the Jaktorow forest in Poland were because the sheath and not the core has been preserved. It turns out that it is merely 46 cm long, which is very small compared to horns of other, earlier specimen. Those were up to three times as long than this sheath, speaking of only the cores. The Jaktorow horn does not look like it is not yet fully developed, so it is probably from a grown bull. Overall, the horn is rather meagre, also compared to earlier sheaths which are thicker and more strongly curved. 

Those were the smallest-horned aurochs specimen preserved that I know of. They all have something in common: they are exclusively from the European subspecies, and they are all from the Holocene. And that might explain why aurochs with smaller horns existed: the presence of humans. I explain in the post linked in the post on large-horned aurochs why I think that anthropogenic influence is the reason for small-horned aurochs to appear. First of all, the aurochs suffered from a fragmented and confined habitat as civilization competed with the aurochs, there likely was hybridization with domestic cattle in the wild in Europe, and the aurochs was hunted for its horns. Trophy hunting is known to affect the morphology of animals. For example, large-tusked elephants have become rare in both Asia and Africa and tuskless elephants became more frequent. Also, the cape buffalo used to have much larger horns in the past than it does today, go here or here and compare with what is average for this species today. I think those factors are the most credible explanations for why smaller-horned aurochs appeared in Holocene Europe, at least I am unable to come up with any other explanation that is plausible for why the European aurochs decreased in horn and body size during the Holocene, as I write in the post linked at the beginning of this post. 

 

Auerrind update

On 7th November, the blog of the Auerrind project posted a little update. It shows some photos of crossbred individuals, f.e. that one: 

© Claus Kropp

It shows the two (Sayaguesa x Chianina) x (Sayaguesa x Watussi) bulls, still at young age. I can't wait to see them fully grown because that combination is the in my opinion most promising one of the project so far. If they grow tall and with large horns, they will make prime new breeding bulls. I think the best mating partner for those bulls is the (Sayaguesa x Watussi) x Chianina cow, because she is of a light colour and has a full set of Chianina chromosomes, which at least has the potential to result in a large offspring with large horns and some sexual dichromatism. I am looking forward to see the future development of these individuals. 

Horn size #1: aurochs with massive horns

All in all, the aurochs was a large-horned bovine. The horns were variable in size, also depending on if anthropogenic influence was present or not (I explain that in that post). With this and the upcoming post, I want to cover that variability. This post is going to cover some of the aurochs remains with the largest horns, to show the upper size limit, the upcoming post is going to show the lower size limit. 

 

-) Various B. p. namadicus skulls 

The Indian aurochs was smaller in overall body size than the European subspecies (in the lack of a complete skeleton no withers height data can be given), but had proportionally larger horns. Only a few crania have been published, and I have seen photos of only three with horns. One of them is at the Geological Survey of India, from the Narmada Valley: 

 

The horn cores are rather wide-ranging and proportionally very large, although there are no size data given for namadicus horn cores that I know of. But I have seen a photo of that skull in frontal view, and assuming that the distance between the horns is 20 cm (which is typical for not so large European aurochs bull skulls), the horn span would have been 133 cm. Since I don’t have data for the length of the cores, I don’t know how long they are. But considering that there is no general rule for how much centimetres the horn sheath adds to the length in a bovine, the length of the horns in life can only be guessed anyway. I assume they easily surpassed one metre. 

Another namadicus cranium shows fragmentary horn cores: 

 

As you see, the part of the left horn core that is preserved is roughly the craniocaudal length of the skull, and it is nowhere near starting to curve inwards, meaning that quite a large part of the horn core is missing. This suggests that this specimen had even larger, very large, horns in life. 

 

-) One suxianensis skull fragment 

The skull fragment I am talking about was published in a Chinese paper (Xie Wanming: A skull of Bos primigenius suxianensis from Anhui. 1988). It is shown from several views: 

 

What becomes apparent is that those horns are ridiculously long. I know no measurements for this skull fragment, so I can only estimate. If the distance between the horns was 20 cm (suxianensis was comparable in size to primigenius), the horn span would have been 137 cm. And this is only a conservative estimate as a 20 cm distance between the horns is actually from the smaller end of the size spectrum of aurochs skulls. Other Bos primigenius suxianensisspecimen show comparably large horns too, but this skull fragment stands out. It also deviates from the other suxianensis specimens in having a rather narrow angle between snout and horns, more comparable to the North African aurochs, while the other specimens had a larger angle between horns and snout. 

An important question is how much the keratinous sheath would add to the length of the horns in life. The aurochs horn sheaths recovered vary greatly in the length they add to the bony core, from 5 cm to 33 cm. In any case, the horns of this East-Asian aurochs were very long. 

 

-) The Wadi-Sarrat cranium 

I have only seen two skulls of North African aurochs so far. One has very large horn cores and is the oldest aurochs skull found outside Asia so far, the Wadi-Sarrat cranium. Photos and measurements of this skull can be found in this paper. The left horn core has a length of 112 cm. With that length, the horn cores are actually longer than those of B. buiaensis, which has very wide-ranging horns and thus appears particularly long-horned. And this is only the bony core, with the sheath the horn would be larger in life. Calculating using the photo and the scale bar, the horn span must be 140 cm. 

 

-) The Sassenberg bull 

I used the Sassenberg bull for many full body reconstructions of the aurochs in the past, which I do not do anymore because I was told it is partly a composite specimen (life reconstructions based on this skeleton always looked a bit weird, now I know why). But the skull is authentic in any case, and it has rather large horns. 

 

-) Skulls found near Rom 

Frisch 2010 describes skulls found near Rome, which are notable because of their particularly large horns. One of them has horn cores of a length of 120 cm, which is the largest horn core length I found in the literature so far. Considering that the keratinous sheath can add up to 40% length to the core, it is easily possible that large-horned aurochs had horns of a length of 1,5 m. But without having the sheath we cannot be sure, it is also possible that it added only a few cm. 

 

-) Two skulls found at Stonehenge 

Stonehenge is not only notable for its stone monument, but also because it is an ancient hunting site where about 50 aurochs have been found. I have seen three well-preserved crania from that location, two of which have massive horns. Go here and here. It’s incredible how thick the horn cores of the first skull are, imagining the horn sheath they must have been very impressive in life. 

 

-) The Viterbo skull 

The skeleton displayed at Viterbo, Italy, is a postcranial skeleton with the skull from another specimen because the original skull was deformed during fossilization. The mounted skull of the Viterbo specimen has very thick and large horn cores. 

 

-) The skull fragment from Groß-Rohrheim 

Groß-Rohrheim in Germany is a Interglacial site in Germany where many of the typical Interglacial megafauna has been found, also including many aurochs remains. One skull fragment is notable for having massive – very large and very thick – horn cores. The horn span is, according to the publication listed down below, 142 cm and the diameter is 15 to 16 cm, the length is 103 and 105 cm. Considering the size of the fragment and the dimensions of the horn cores, this specimen must have been an absolutely impressive sight in life. 

 

-) The Faborg skull 

This cranium was found near Faborg in Denmark and is exhibited at the National Museum of Copenhagen, next to the Prejlerup bull skeleton. According to a picture description I found on google, the horn span of that specimen is 114 cm. 

 

-) The possible siciliae skull 

The skull from Sicily that might be of the dwarf subspecies B. p. siciliae shows very long and wide-ranging horns. Since the overall body size of the animal was small if it really was from the dwarf subspecies (which had a withers height of only 130 cm), it is questionable if the absolute size of the horn cores is as impressive as in the those from the mainland subspecies, but proportionally they are very large. 

 

Looking at the largest-horned aurochs, it can be concluded that Bos primigenius was among the largest-horned bovines that would be around today if it had not been for anthropogenic influence. Only those of the wild Asiatic water buffalo are larger among extant bovines. 

It has to be noted that these specimens I presented here are only the tip of an iceberg, and it is hard to say what was “average” for the aurochs, and if there were differences between the subspecies. The point of this and the upcoming post is to show the extreme ends of the horn size spectrum. The next post is going to focus on small-horned aurochs. As a little spoiler (or teaser): they all have something in common, something that might reveal why their horns were small compared to the huge horns of the specimens presented in this post. 

 

Literature 

 

Van Vuure, 2005: Retracing the aurochs – history, morphology and ecology of an extinct wild ox. 

Frisch, 2010: Der Auerochs – das europäische Rind. 

Von Koenigswald & Menger: Ein ungewöhnlich großer Schädel vom Auerochsen (Bos primigenius) aus dem letzten Interglazial von Groß-Rohrhiem bei Darmstadt. 2002. 

 

 

More than 200 genes were involved in yak domestication

This is not exactly news, but from a paper I only discovered recently. It’s by Qiu et al. from 2015 and reports that 209 genes were found to be likely involved in the domestication of the yak about 7000 years ago [1]. 

Of these 209 genes, more than 30 are associated with brain and neuronal development, 19 other genes with behaviour and only a few genes with physical appearance and economically relevant traits [1]. 

This could provide insights to the question how many genes were affected in the domestication of cattle, which would tell how many genes would have to be edited in order to recreate the aurochs with genome editing. It makes a difference if one would deal with 20 genes, or 2000, for technical and practical reasons. Considering the findings from yaks, the number of genes where aurochs and cattle differ might at least be in the three-digit area. It has to be kept in mind that yaks are not nearly as strongly domesticated as highly derived cattle breeds. Basically all yak breeds are landraces, and gene flow from the wild populations into the domestic yak has never ceased to occur [1]. 

 

[1] Qiu et al.:  Yak whole-genome resequencing reveals domestication signatures and prehistoric population expansions. 2015. 

 

 

Koniks with a standing mane in Oostvaardersplassen

Some Konik ponies have a standing mane. This is likely the result of Przewalski's horse introgression, as the crossing-in of this wild equine is documented in the Konik pedigree [1]. I have seen such specimen especially often on photos from Polish breeding sites, such as Popielno, which is one of the most important Konik breeding sites in Poland. There are also very Konik-like ponies in Germany that can have an upright mane, but those are likely to be Heck horses (both breeds are used indiscriminately in grazing projects, there is no breeding book so they are virtually indistinguishable in Germany). But the ponies at Oostvaardersplassen are "pure" Koniks in any case, mostly purchased from Popielno. I have not seen any OVP ponies with a standing mane until I found a relatively recent video on youtube, go here. Sometimes a domestic horse can have a standing mane when it is not fully grown yet (all foals have a standing mane), and sometimes it looks as if the horse has a standing mane when viewed from the side when the bulk of the longer hair of the mane falls to the other side and the shorter hair at the edges of the mane are standing, but I think in this case it is rather clear that those are truly fully grown Koniks with a standing mane, see shots like 1:27. It is interesting to see that also in OVP, the largest Konik breeding site in western Europe, there are individuals with a standing mane. Particularly interesting is the question if the frequency of individuals with a standing mane would increase over time if it provides a fitness advantage, as there is no artificial selection on those ponies. 

[1] Jaworski 1997: Genealogical tables of the Polish primitive horse. Polish Academy of Sciences. 

When and how should the "breeding-back" projects cooperate?

Today in the 2020s, there are several “breeding-back” projects focusing on the European aurochs. I think that there can be no question that it would be most beneficial for “breeding-back” as a whole in order to achieve the goal – that is, a population of cattle that is as aurochs-like and at the same time as genetically diverse as possible to be fit for a reintroduction into Europe’s nature – if the projects would one day cooperate in some sort. The question is: when and how should the projects cooperate? 

First of all, it has to be visualized why cooperating between the different “breeding-back” projects would be beneficial. It would be helpful to maintain a higher level of genetic diversity than if the projects would work separately. Maintaining a certain level of genetic diversity while at the same time creating a homogeneously aurochs-like population is one of the challenges of “breeding-back”. This is less of a challenge when there are several projects that cooperate. When the crossbred cattle used in the breeding projects are bred selectively for a more homogeneous phenotype, some alleles become fixed. In the process of homogenizing the population, the genetic diversity is reduced. However, in each different project, different alleles become fixed. And when the populations of the projects are eventually combined to one large gene pool, the genetic diversity is larger than it would be if there was only one project. As an example, Project 1 has a cattle population with the alleles A, B, C and D on loci responsible for any trait that is not affected by the breeding objectives of “breeding-back” but relevant for genetic health. Project 2 has a cattle population with the alleles E, F, G, and H. Both projects establish a homogeneous aurochs-like phenotypes, and reduced their genetic diversity in the process. In Project 1, only the alleles B and D remained in the populations, being present homozygous now. D is deleterious when homozygous. In Project 2, only the alleles F and H remained in the now very aurochs-like animals, and allele F is deleterious when homozygous. So both projects achieved a very aurochs-like phenotype at the expense of genetic diversity. When both projects combine their gene pools into one large gene pool, we have a population with the alleles B, D, F and H. Now the allelic diversity is larger again and the number of individuals being homozygous for deleterious alleles dropped significantly and since both projects have very aurochs-like animals, the degree of aurochs-likeness was not affected by combining the two lineages. This is of course a simplified example, but combining two or more lineages always results in a greater allelic diversity and if all the individuals of those lineages are very aurochs-like, genetic diversity would not go at the expense of resemblance to the aurochs, which would be the case if a not related non-“breeding-back” breed was crossed in to increase the genetic diversity. 

While combining the different “breeding-back” lineages would be beneficial in the long run, it does not make sense if the different projects are yet at different levels of “breeding-back” progress. For example, if one project has great animals and another project is just starting or has animals of modest resemblance to the aurochs, and they exchange animals, the result being one project benefiting in terms of aurochs-likeness and one project perhaps introducing undesired traits from the breeds of the other projects, while the genetic diversity would not necessarily increase because the process of achieving very aurochs-like animals is not completed yet. Rather it could lead to the contrary, because the project with the less good animals will use the great animal from the other project on a larger scale in order to improve the aurochs-likeness of their animals, thereby narrowing its genetic diversity. Thus, I think exchanging animals between the “breeding-back” projects really only makes sense if all of them are at the same level of aurochs-likeness. 

When one project has an animal with a trait that all the other projects lack, for example if one project has absolutely perfectly aurochs-like horns and all the animals of the other projects have bad horns, it certainly would be beneficial for the aurochs-likeness of the other projects to acquire animals from the project with the perfect horns, but it would also narrow the genetic diversity in all of them. Therefore, it would be smarter before exchanging animals to ask the following questions: Why are the animals of the other project better in this respect? Did they use a breed that contributed the traits that are lacking in the one project, and could this or another breed with that trait be used in the project? For example, if one project used only medium-sized breeds as founding breeds, and another project included a very large breed and thus has larger animals, it would be the best decision for the overall genetic diversity of the “breeding-back” pool to cross-in very large founding animals instead of depleting the diversity by using an individual from the other project. 

Therefore, I think that for now, the different “breeding-back” projects should focus on their own gene pool and how they can improve the aurochs-likeness of their animals within the gene pool. That is not to say that never ever should individuals, cows in particular, be exchanged between the projects. Only the large-scale use of individuals from other projects, f.e. as sires for many years, however aurochs-like it may be, should be avoided so that the overall genetic diversity is not reduced. But once all of the projects achieved the same level of aurochs-likeness, i.e. that all of the animals of all of the projects are large, have the right colour, the right horns, the right sexual dimorphism, the right morphology et cetera, I suggest to exchange animals at a regular basis in order to create genetically diverse and healthy individuals. In zoos and reserves, the animals are exchanged on a regular basis in order not to diminish the genetic diversity of the herds, and “breeding-back” should do so as well once all projects have reached the same level of quality. The result would be one large and genetically diverse population of very aurochs-like cattle that are fit to be established in European wildlife reserves. 

 

 

An animation of an aurochs running

I have not seen an anatomically correct animation of an aurochs yet, so I decided to try one myself. I made a little video of an aurochs bull running. It was done by making animated GIF consisting of 16 drawings of the same individual during running, based on a GIF of an American bison running. I converted the GIF into a video, and here is the result: 

Should we allow paraphyletic genera?

This post is a rather theoretic one, and some might wonder what it has to do with the main topics of my blog. However, the question if we should allow paraphyly in some cases in taxonomy is relevant for the naming of species, some of which are in the focus of this blog. 

For those who are not familiar with the term “paraphyletic”, it describes when a group is not a natural group in the phylogenetic sense, a group that has a common ancestor but does not include all descendants of this common ancestor. Paraphyletic groups are avoided in modern taxonomy because treating them as if they were the same as mono- or holophyletic groups (such that have a common ancestor and include all of its descendants) is comparing apples to bananas. To illustrate that, I take my favourite vertebrate group as an example: dinosaurs (I am actually quite a big fan of Mesozoic paleontology ever since I was a kid). It is nowadays very well-established that birds descend from non-avian dinosaurs, so that they are part of the Dinosauria clade. Why? Because Velociraptor is closer to birds than Tyrannosaurus, and Tyrannosaurus is closer to birds than a Triceratops. If birds weren’t dinosaurs, Velociraptor isn’t a dinosaur either. But in this case, Tyrannosaurus would not be a dinosaur either, because it is closer to birds and Velociraptor than to Triceratops. And so on. Consequently, birds are dinosaurs because they are nested on the dinosaur branch of the phylogentic tree. Dinosaurs themselves are part of what has traditionally been called reptiles. That means that birds should be reptiles, because birds are dinosaurs. That sounds crazy when comparing a lizard with a duck, but that’s evolution. A crocodile is closer to birds than it is to lizards, and a Tyrannosaurus is closer to birds than a crocodile. Thus, the group of reptiles in the classical sense is not a natural group because there is that decision to regard some members of this clade not as members of this group for historical reasons that go back to the time of Linnaeus. This is called paraphyly. Therefore, Reptilia is not the same as Aves (an impression that can be created by the traditional rank system of four tetrapod “classes”), rather there is the Sauropsida clade, that includes a common ancestor and all its descendants, living and extinct. On this clade, there is the Aves clade, which includes all birds. Reptilia, however, is not a clade. It is a collective term for all sauropsids that are not birds, including not very bird-like animals such as lizards, and extremely bird-like animals such as Velociraptor mongoliensis. Since paraphyletic groups make the taxonomical system much more arbitrary than it already is, they are discarded in the modern (phylogenetic) systematics, otherwise one would compare apples and bananas. Systema naturae came 101 years before Darwin’s On the Origin of species and our knowledge of extinct organisms. 

Another problematic reminiscence of the original taxonomy that came before our knowledge of evolution are “ranks” for clades. That is the hierarchical system of species, genus, family, order, class and so forth. Nobody was ever able to define these ranks objectively and universally – how can we know that Hominidae, Tyrannosauridae and Canidae are of the same “rank”? There is no definition. Aves, for example, is considered one of four tetrapod “classes”, descending from reptiles, which were considered a “class” themselves. Now we know that Reptilia is not a natural group and most researchers use the name Sauropsida instead, but Sauropsida and Aves cannot both have the same “rank” as Sauropsida is a much more inclusive group. The same problem exists with any rank. For example, the Raphidae (dodos and its close relative Pezophaps solitaria) was downgraded to a subfamiliy (Raphinae) because it is obviously nested within the Columbidae (pigeons), so both cannot be the same “rank”. Therefore, “ranks” make taxonomy even more arbitrary and only worked back in Linnaeus’ time when we had no knowledge of evolution and extinct animals (as a side note, I wonder if Linnaeus would have questioned his own system if he would have had the possibility to classify living Velociraptor or Brachiosaurus, which are obviously between the “classes” of reptiles and birds in his understanding). “Ranks” for clades are not considered to be of any factual relevance in modern systematics anymore. 

This brings us to genera, which are ranks as well. However, genera cannot simply be ignored as they are perpetuated by the binominal nomenclature in biology. Each name for a species is composed of a genus epitheton and a species epitheton. Some species share the genus epitheton because they are considered members of the same “genus” (for example Panthera leo and Panthera tigris). A genus is based on a type species, and all the other species are assigned to that “genus” when they are considered “similar enough” to the type species to be considered members of the same “genus”. The problem is, however, nobody ever defined how to measure this similarity objectively and universally and how much of that measured similarity is “similar enough”. At least not that I am aware of. But we would need something like that in order to create a consistent concept of a “genus” that is necessary because it is relevant for the naming of species. The perception of what is “similar enough” also shifts with time. Back in the 18^th century, a “genus” was about as inclusive as is a “family” is nowadays – at least in some cases (take elephants: back in the 18^th century, there was Elephas maximus, Elephas africanus and Elephas primigenius, which are nowadays considered three different genera, Elephas, Loxodonta, Mammuthus). If that was not problematic enough, there is the evolutional process going on. Species evolve into new species, the phylogenetic tree continues to grow. And as a consequence, there is inevitably the case that one genus evolves into another. On the cladogram, the resulting “genus” is paraphyletic. For example, the Haast’s eagle Harpagornis moorei is nested within the “genus” Hieraaetus, the two Bison species nest within the “genus” Bos. But saying “that genus is paraphyletic” may be not entirely correct, as a “genus” is not a clade but a “rank” that is often congruent with a given clade. A genus is defined as all species that are “similar enough” to the type species and the type species itself. Nobody defined a “genus” as a clade, so it cannot actually be paraphyletic. So, is Harpagornis moorei “similar enough” to the type species of Hieraaetus, H. pennatus? Are Bison bonasus and Bison bison similar enough to the type species of Bos, B. taurus/primigenius to be considered members of that genus? The answer is entirely subjective, and there is no way to objectively and consistently measure “similar enough”. Perhaps Harpagornis moorei is more distinct from Hieraaetus pennatus than Bison bison is from Bosprimigenius. Including Harpagornis moorei into Hieraaetus means that also a hypothetical descendant of H. mooreiwould have to be included into Hieraaetus because it nests on this clade. That means that till the end of all days all species that would have evolved from Harpagornis or another member of the Hieraaetus clade, however distinct from the Hieraaetus type species they may be, have to be included into the “genus” Hieraaetus to avoid paraphyly. And considering that each genus descends from another genus, right down to the last common ancestor of all organisms classified under the rules of the ICZN, all animals are necessarily members of the same, ancestral “genus”, if a paraphyletic “genus” is to be avoided. That means that all genera are essentially synonymous. This makes the concept of a genus meaningless, if we are consistent with the approach that a “genus” should never be paraphyletic. But a “genus” is a rank and not a clade, and ranks are based on arbitrary subjective decisions based on similarity to a defined type species, and not on clades. They are often congruent with clades, yes. And regardless of how we name the species, Bison bison is a member of the Bos clade, and Harpagornis moorei is a member of the Hieraaetus clade (by the way, the same problem also goes for species. There is no definition of a species that works universally, but if we look at the individual level, all species in the history of evolution are paraphyletic on a cladogram, because some individuals assigned to the ancestral species will necessarily closer to the new species than to the earliest member of the ancestral species. Looking at the time scale, the concept of a species is artificial and arbitrary, and species are definitely not clades). Another way to avoid genus paraphyly instead of lumping is splitting. For example, Loxodontaafricana and Loxodonta cyclotis are “similar enough” to be considered a member of the same “genus”. But it turned out in recent genetic research that L. cyclotis is actually closer to Palaeoloxodon than to L. africana. How to avoid the paraphyly? If L. cyclotis is not “similar enough” to Palaeoloxodon, it might be assigned to its own “genus” because it is closer to Palaeoloxodon, but not similar enough to be a Palaeoloxodon species. That might work when looking only at Loxodonta and Palaeoloxodon. But all genera evolved from another genus. There will always be species that are closer to the descending genus than to the type species of a given genus. As a consequence, each species would end up with its own genus, making the concept of a genus moot. So, both approaches to avoid genus paraphyly, both lumping and splitting, would, when applied consistently to all organisms, make the genus as a rank useless – the problem is more fundamental, because a rank is treated as a clade here. 

So, considering that the concept of a “genus” as a rank is arbitrary and subjective, and the concept of a “genus” as a clade makes the term absurd because all living organisms would either be members of the same ancestral genus or each species would be its own genus so that no genus is paraphyletic, what should we do? At the moment, the way it is, it is inconsistent. See the example with Harpagornis. The concept of a genus, however, is tied to the binominal nomenclature. If we change the binominal nomenclature, we will have to change the names of millions of organisms. And naming a species with two words is more definite than just one word. But we could do something intermediate: erecting a new first epitheton for each species that is not a type species of an already existing “genus”. That would also be a lot of work, but it would be more consistent and compatible with the evolution of species and the cladistic system. In some cases it would work easily, when the species epitheton is a latin name on its own. Take Panthera as an example. I was unable to find out what the type species of Panthera is, but it would work in all five species: Parduspardus, Leo leo, Tigris tigris, Onca onca, Uncia uncia. Taking the Bos clade, it would work as well, because a number of synonynomous genera or subgenera have been erected or some species epitheta are just a latinized version of the name of the species: Bos primigenius, Gaurus gaurus (gaur), Bibos javanicus (banteng), Novibos sauveli (kouprey), Poephagus mutus (yak), Bonasus bonasus (wisent, bonasus is just another name for bison, by the way) and Bison bison(American bison). For a lot of species, new first epitheta would have to be erected, especially for fossil taxa. That would be a lot of paperwork, but let us be honest, each scientist dreams of naming a new taxon, so that “Name, Year” will be mentioned next to the name forever. So, I think that many would not mind and take that opportunity to immortalize their own name by naming a new taxonomical name. And since it is not the description of a new genus that includes several species and has to be differentiated from other genera, no profound diagnosis is necessary because the species it refers to already has been diagnosed. 

I know that this is a radical approach, and it would take decades until it is established and the rules of the ICZN would have to be changed. But it would be consistent, less arbitrary, and compatible with evolution. As already mentioned, Linneaus came 101 years before Darwin, and taxonomy has already reacted by discarding paraphyletic groups. Maybe the next little revolution that is necessary to transfer taxonomy into the 21^st century is to abandon the concept of a genus. The alternative is, if taxonomy is supposed to be consistent, to allow “paraphyletic” genera (which are not really paraphyletic since they are not clades). 

 

How large were the largest aurochs?

The size of the European aurochs has been both over- and underestimated. The largest size estimate given in the literature I have seen so far was 230 cm at the withers (I don’t remember the source, unfortunately), the smallest for bulls was 145 cm. The latter is definitely inaccurate, as there is no evidence for European aurochs bulls with a withers height noticeably below 160 cm. But what was the upper size limit of aurochs bulls? 

 

The preserved skeletal material is the only reliable indicator for the size of the aurochs available as no living aurochs were measured. Complete skeletons are considerably rarer than finds consisting only of fragmentary material or single bone elements, but they are the better indicator for the size of the animal in life. But in order to give an accurate idea of the size of the living animal, it has to be mounted anatomically correct. Alas, most skeletal mounts of the aurochs have anatomical flaws. These flaws can make the withers height of the skeleton smaller or larger, depending on what is wrong. The Prejlerup bull skeleton, however, is mounted fairly correctly. I was unable to find a reliable source on the height of the skeleton. Using a photo of the skeleton in profile view with a person next to it whose height I know, I calculated the withers height of the skeleton and it turned out to be around 190cm. This is the largest size for a complete aurochs skeleton that I know of. However, it must be considered that the skeleton lacks the soft tissue surrounding the bones, so that the skeleton appears smaller than the individual was in life. For example, the intervertebral discs add quite a few centimetres to the length of the skeleton. The connective tissue between the leg bones adds to the height of the skeleton. The hooves alone might add 2 to 3 cm. And lastly, the skin and fat tissue adds one or two more centimetres. Therefore, it is not unlikely that the Prejlerup bull was 5 to 10 cm taller in life than its preserved skeleton. Thus, the bull might have been 195 to 200 cm tall at the withers in life. 

The Prejlerup bull is the largest complete skeleton from the European aurochs, but probably not the largest specimen found so far. Unfortunately, these specimens are not known from complete skeletons but from fragmentary, isolated remains. The perhaps largest European aurochs found is the London skull, exhibited at the British museum of London, which reportedly has a length of 91,2 cm [1]. This is very large, also compared to other aurochs specimens. The skull length in the other skulls observed by Nehring 1889 was between 64 and 72 cm [1]. Unfortunately, I do not have access to the original source by Nehring, so I don’t know if he specified what he means by “length” in his work – the length from the caudal end of the neurocranium to the cranial end of the nasal bone or to that of the premaxilla? I am cautious considering the huge size of the given length and assume it is from the end of the neurocranium to the premaxilla. This is still very large. 

How large was the animal that belonged to the London skull? In the lack of a complete skeleton, there is no other possibility to get an idea of the total body size than to extrapolate the size based on complete skeletons of other bulls. I used photos of four bull skeletons (Prejlerup, Vig, Sassenberg, Store-damme) in clear profile view and started to calculate. At first, I calculated the absolute skull length of the skulls of the skeletal mounts that I know the withers height of, the Sassenberg (165 cm), Prejlerup (possibly 190 cm) and Store-damme (175 cm) specimen in order to check if the calculation is plausible. The results were a skull length of 79 cm for the Prejlerup, 71,5 cm for the Sassenberg and 70,3 cm for the Store-damme skeleton. The latter two are in accordance with what was found by Nehring, the Prejlerup is slightly larger but the whole skeleton is larger than the other two. So the calculation results in plausible skull sizes for the given skeletons. The relation of the skull length to the withers height was 2,4 in the Prejlerup, 2,307 in the Sassenberg and 2,49 in the Store-damme and Vig specimen. Those are very similar values, the Sassenberg bull has the proportionally largest skull, but it has to be noted that it is partly a composite specimen. Under the assumption that the proportions of the London specimen were comparable to the other specimen, I calculated the possible withers height for the 91,2 cm long skull. The results were: 

If the proportions were identical to that of the Prejlerup bull: 218,4 cm

If the proportions were identical to that of the Sassenberg bull: 210 cm 

If the proportions were identical to that of the Store-damme and Vig bull: 226 cm 

If the proportions were intermediary between those of all four: 220,1 cm 

These are very large sizes. But we simply have that skull that was about 28% larger than what was found to be the average by Nehring 1889 – unless Nehring’s 91,2 cm for the London skull are inaccurate. However, I do not know Nehring’s sample size and if his sample was representative of aurochs from the northern half of Europe (which the other skeletons and most likely the London skulls were), and if all of the examined skulls were from males as females were smaller. There is at least one skull that might be comparable in size to the London skull, the Berlin skull. I saw this cranium two times, and I can firmly tell, it is huge. I don’t know if anyone measured that skull, however. But assuming the Berlin skull is of the same size or a similar size as the London skull, are the results of my calculation plausible? 

Well, there are several possible error sources. 

1. Nehring’s 91,2 cm for the London skull might be inaccurate 

2. The bull that belonged to the London cranium might have been oddly proportioned, i.e. with a head larger than usual for aurochs 

3. The photos I used might not reflect the natural proportions of the skeletons (I think they do) 

4. The measurements I took from the photos might be inaccurate or imprecise (in this case, the resulting absolute skull sizes for the skeletons would not be plausible, but they are) 

5. The four specimens do not reflect the variation in proportions within the European aurochs (since the values for the relative skull length are all very similar, except for the one specimen that is partly a composite, I do not think this is necessarily the case). 

The results of these calculations would certainly be more accurate if I had the possibility to take measurements from the actual bones, which I don’t have. But is a size between 210 and 226 cm for the largest aurochs plausible? Large wild yaks reach sizes up to 205 cm, gaur bulls 220 cm, and the extinct Bos (Bison) latifrons is said to have had a withers height of 230 cm. It must be considered, however, that these species have different proportions and longer spinal processes, resulting in a larger withers height. Thus, I am cautious. But I consider the 210 that result from calculating with the Sassenberg bull actually plausible for the largest aurochs. What would definitely be necessary is a) someone has to measure the London skull and Berlin skull to see if they really exceed 90 cm b) other suspiciously large aurochs bones, such as limb elements, pelves etc., should be checked – if they are by one fifth larger than the same elements from the complete skeletons, that is another hint that there were aurochs larger than 200 cm. However, extrapolating the size of an animal based on single skeletal elements is very risky in general. On the other hand, the London skull and the Berlin skull are noticeably larger than the skulls from complete skeletons which we know how tall they are. We need more complete material of very large aurochs to be sure how large they actually were.  

 

Literature 

 

[1] Frisch, W.: Der Auerochs – das europäische Rind. 2010.