Extinct megafauna that could be revived using genome editing

Humans wiped out countless species of animals. Some of those species, particularly those that died out comparably recently, might actually be retrievable. Usually, cloning comes to mind when talking about reviving extinct animals. However, somatic nucleus transfer for reproductive cloning requires an intact cell and not just the DNA of the animal, which is why it is not available for most species wiped out by man. However, there are a few megafaunal species that have been wiped off from which we have at least one and in some cases several complete genomes. If there is a still extant species that is closely related and would make a suitable surrogate, it would be possible to exchange the alleles specific for species A with those for species B and thus creating a viable cell with the genome of the extinct species in question with genome editing. This limits the number of extinct animals that could be revived. For example, I would imagine it to be pretty difficult if not impossible for a species like the thylacine, which has been evolutionary separated for 30 million years from its closest living relatives. In some cases, it could be easy and much less effortful because of the lower number of genes that differ and the suitability of the surrogate because the animal has a very close living relative. In this post, I present a number of megafaunal species from which full genomes either have been acquired or at least could potentially be acquired and which have a more or less closely related relative that can be used for genome editing and as a surrogate. The mitochondrial DNA of the resulting animal would be that of the donor cell, which would be from the related species. However, as mitochondrial genes are highly conserved among mammals this would not have much of an influence. Using closely related species also has the advantage that the behaviour will be rather similar, especially among the large herbivore species that I am going to list. This makes the rearing by a surrogate mother and socialization of the result less problematic or maybe not even an issue at all. 

I see reviving an extinct animal that has been wiped out by man as a contribution to species conservation just as breeding an endangered species or subspecies. One might ask, particularly in the case of wiped-out subspecies, why doing that at all if there are suitable ecological proxies. Occasionally some even question the need to conserve endangered subspecies such as the Northern White rhino because their conspecifics from other subspecies would function ecologically the same or very similar. Personally, I cannot relate to that mindset. Conservation is about preserving biodiversity and the preservation of evolutionary more or less distinct subspecies is a vital part of that. The same goes for reviving extinct species or subspecies – it would greatly increase the biodiversity again, after it has been depleted by man when the species or subspecies was wiped out. 

 

Bubal hartebeest, Alcelaphus buselaphus  

This animal is sometimes also considered a subspecies, but that question is merely taxonomical and not relevant for “de-extincting” the animal. In any case, other members of Alcelaphus could be used for genome editing and as a surrogate. Many individuals must have been preserved as trophies, and it is potentially possible to acquire full nuclear genomes from them. 

 

Bluebuck, Hippotragus leucophaeus  

Other members of Hippotragus could be used as a surrogate and for genome editing. It can be tried to acquire a fully nuclear genome from taxidermies.  

 

European aurochs, Bos primigenius primigenius

One full nuclear genome has been resolved in 2015 from a well-preserved Neolithic bone. Considering the richness of recent aurochs material, it could be possible to obtain quite a few more complete genomes. And there is a very close living relative, modern cattle. The number of genes that would have to be exchanged would probably be lower than in most of the other cases I am listing here, and also the surrogate and the procedure of implanting an embryo would be completely unproblematic. And considering the similarities in behaviour between cattle and aurochs, socialization will not be problematic either. For these reasons, I consider the aurochs one of the most realistic candidates for a revival through genome editing. Even if the resolved genome remains the only one to be fully resolved, one revived aurochs individual still can be outbred using aurochs-like cattle. I wrote a post on that a few years ago. 

 

Several types of wild horses 

There are well-preserved mummies of Siberian wild horses, Equus caballus lenensis, and one of the Yukon wild horse, Equus caballus lambei, so it could be possible to obtain fully resolved nuclear genomes from that. A domestic horse could be used for genome editing and as a surrogate. Even if only one genome can be obtained, the revived horses can be outbred with Przewalski’s horses and/or robust landraces in the same manner as I suggested for revived aurochs. 

 

Kouprey, Bos sauveli  

Numerous kouprey specimen have been preserved as trophies and one skin. It could be possible to obtain full nuclear genomes from that very recent material. The closest living relative is the Cambodian banteng which hybridized with the kouprey in the past. It can be used for genome editing, as a surrogate and even for outbreeding if necessary. 

 

Quagga, Equus quagga quagga  

The quagga is not and cannot be bred-back from extinction with living Plains zebras, which is why it would be desirable to try to acquire full genomes from the numerous preserved skins and the few skeletal material that is preserved of this zebra. The zebras of the Quagga Project can be used for genome editing, as a surrogate and outbreeding if necessary. 

 

Pyrenean ibex, Capra pyrenaica pyrenaica  

This is the only extinct animal that has been cloned so far, unfortunately the clone died shortly after birth. Genome editing with individuals from other subspecies of Capra pyrenaica could be more successful, they can be used as surrogates and for outbreeding. 

 

Steppe bison, Bos (Bison) priscus  

There are plentiful of remains from steppe bison, including soft tissue. Perhaps it would be possible to obtain full nuclear genomes from that. Needless to say, that still existing bison, be it European or American, can be used for genome editing, as a surrogate and outbreeding. 

 

? Woolly mammoth, Mammuthus primigenius  

Currently, there is no de-extinction project in the strict sense focusing on the woolly mammoth. There is the attempt to create a “mammophant” by introducing mammoth alleles for certain traits into the genome of an Asian elephant, what is not what I would consider de-extinction in the strict sense. If doing that is possible, it might also be possible even if more effortful, to exchange all alleles of genes where Asian elephant and woolly mammoth differ. However, since implanting an embryo into an elephant is very complicated, and those who want to create plan to use an artificial womb, a technique which does not exist hitherto, I wonder if it is feasible to recreate the woolly mammoth for practical reasons. 

 

Caucasian Wisent, Bos (Bison) bonasus caucasicus  

Several skins and trophies of this wiped-out subspecies (or species or variety, there is no consensus on its taxonomic status) exist, so it could be possible to obtain full nuclear genomes from it. European bison of the Lowland-Caucasus line, which partly descend from the last Caucasian wisent bull, could be used for genome editing, as a surrogate and for outbreeding. Obtaining genomes from remains of wisent prior to the bottleneck in the 20^th century could also help to greatly increase the very limited genetic diversity of this endangered bovine. 

 

Cave lion, Panthera spelaea  

Several very well-preserved pubs of this feline have been found. It might be possible to acquire full nuclear genomes from that, and the closely related actual lion would be suitable for genome editing and as a surrogate. 

 

Schomburgk’s deer, Rucervus schomburgki  

Some remains of this deer species exist, a sister species from the Rucervus clade could be used for genome editing and as a surrogate. 

 

Japanese sea lion, Zalophus japonicus

There are taxidermied specimens of this sea lion, related species of the Zalophus clade can be used for genome editing, as a surrogate and possibly outbreeding if necessary. 

 

Caribbean monk seal, Neomonachus tropicalis

There should be some remains of this recently extinct species, the related Hawaiian monk seal can be used for genome editing, as a surrogate and possibly outbreeding if necessary. 

 

One common objection against the revival of extinct animals is “one individual is not enough to build a population”. Apart from the fact that even one individual could tell us a lot about the extinct animal species/subspecies, it could be possible to get several genomes of those recently extinct species. Getting the full genome of five or ten individuals from different regions and times would probably enable to get a genetic diversity comparable to that of the modern wisent population, which descends from only twelve founding individuals from the same population. Some wisent individuals show inbreeding-related problems, but not to the extent that it threatens the survival of the species. An even more extreme example would be the Mauritius kestrel. Apart from that, related species/subspecies can always be used for outbreeding to add genetic diversity. Hybridization among related species with neighboring or overlapping distributions is very common in the animal kingdom. 

 

The colour of Indian aurochs cows

We know nothing about the colour of the Indian aurochs with certainty, except for the fact that it must have had the E⁺ allele on the Extension locus, because the majority of zebus have it and it is also found in taurine cattle, suggesting that it was already present in the common ancestor of the primigenius and namadicus lineages. That means namadicus must have had the colour that has both phaeomelanin and eumelanin (red and black pigment), dispersed in some pattern across the pelage, a white muzzle ring and testosterone-dependent eumelanisation. Very likely sexual dichromatism was present, i.e. that bulls and cows had different colours. Some zebu breeds have retained a certain degree of sexual dichromatism, with the bulls being slightly darker than the cows. The colour of the cows is in the focus of this post. 

Many zebu cows that have the production of phaeomelanin enabled (the mutation disabling the production of red pigment is quite common among zebus and perhaps originated in that lineage) are almost homogeneously reddish-orangish-brown, with a dark brown dorsal stripe (that is not always present), lightly coloured rings around the eye and a lightly coloured area on the ventral side of the trunk and the inner side of the limbs. Black or very dark areas are (almost) absent. A colour consisting of a reddish-brown base colour with a dark dorsal stripe is sometimes also found in taurine cows, albeit rarely. It is much more common in zebu cows. The only black or very dark areas in zebus having that colour are, if present, along the anterior side of the forequarters, either down to the carpals or to the toes. I consider it quite likely that this is the original colour of female Indian aurochs cows and it can be seen in breeds like Red Kangayam. 

The reason for my assumption is that female Java banteng have a very, very similar colour. They are orangish-reddish-brown, with a dark dorsal stripe, lightly coloured areas on the inner side of the limbs and the ventral side of the trunk, they even have the dark areas on the forelimb, except for the part that is completely devoid of pigments. In fact, if those white “socks” and buttocks were not there, the colour would be almost identical. I see two possible explanations for that similarity: a) the common ancestor of both species had this colour and it is the ancestral trait, thus was also present in the Indian aurochs b) introgression from banteng into the zebu after domestication. As for the latter possibility, the introgression of banteng or their domesticated form Bali cattle is documented for some lineages of zebus. But I consider it less likely that this is the reason for the similarity in coat colour as in this case this colour would not be found in taurine cattle too, which it is, albeit rarely. Also, Red Kangayam are found in Southern India, where banteng introgression is less likely for geographic reasons. This makes the assumption that it is inherited from a common ancestor more likely, since such a close similarity in more or less closely related species is probably not a coincidence. If this colour was already present in the common ancestor of the Java banteng and the zebu, it is the most parsimonious assumption that it was present already in the Indian aurochs. That colour is in fact not all too special. Wildtype coloured calves in taurine and indicine cattle are usually reddish brown with a dark dorsal stripe, the cows retaining this dark dorsal stripe and having almost no black or dark brown areas just means that the process of growing what is the adult coat colour in bulls is stopped earlier than in European aurochs cows, which often had black heads, necks and legs or were even black with a red colour saddle, as cave paintings show. 

However, this colour being the result of banteng introgression into zebus after domestication cannot be ruled out completely, and in the lack of artistic depictions showing the Indian aurochs and the fact that female zebu appear in a wide variety of colours we can only guess what its colour was like. I think the colour shown by the Red Kangayam is a very plausible one for namadicus cows, but this has to remain a speculation, as long as we do not have any direct evidence of the coat colour of the Indian aurochs. 

 

Are domestic cattle truly smaller than the aurochs?

The question in the headline of this post will immediately be answered with “yes, obviously” by most people, which is understandable as the European aurochs is known for being a very large bovine and the size reduction is one of the most noticeable consequences of domestication in cattle. However, there is one aspect that should be considered. 

It starts with how to define body size. In mammals, one of the most widely used parameter of body size is the withers height. Going by this factor, it is obvious that the aurochs was much larger than most domestic cattle – very large breeds like Chianina or Bhagnari being the exception. Go here for my post on how large the largest aurochs might have been.

When naming the largest living land animal, most people will say it is the African elephant. This is because it is the heaviest terrestrial animal. But going by height, it would be giraffes, and going by length, the reticulated python would be the second-largest terrestrial animal on earth. Yet, those species are rarely considered the largest terrestrial animals. So, is mass the most important body size parameter? It is certainly an objective one, as it is almost independent of the morphology and bauplan of the animals (with the exception of birds which have an air sac system and pneumatized bones, which is why their bodies have a lower density than those of other terrestrial animals). If we go only by mass, let’s examinate if cattle are truly smaller than aurochs. 

One problem is that we do not know the exact weight of aurochs. No aurochs were weighted, so we can only guess by using extant wild bovines as a comparison. Since the males are larger than the females in bovines, I only refer to the mass of males in this post. Perhaps the weight of the aurochs was somewhere in the range of banteng, wisent and wild yaks, which would be between 700 and 1000 kg. Wild yaks have a slightly more elongated and more robust morphology than the aurochs had, but have a similar height compared to the largest aurochs (which is roughly 2 metres) and their weight is around 1000 kg. While yaks are built slightly more massive than aurochs, they have a higher shoulder hump, what influences the withers height. So it could in sum be that a 200 cm tall aurochs was roughly the same weight as a 200 cm wild yak. That would mean that a 160 cm aurochs had only about 510 kg. The wisent has similar proportions and a roughly similar build. The record for wisent height is 188 cm, for the weight it is 840 kg in wild-living animals. That means a 2 m wisent would be 1011 kg and a 160 cm wisent would be around 500 kg. Banteng reach up to 190 cm and 900 kg weight, which would be 529 kg in a 160 cm banteng. Since all those three bovines result in a similar weight range, maybe it is reasonable to assume a weight of around 500 kg for a 160 cm aurochs, and 1000 kg and slightly above for a 200 cm aurochs. Keep in mind that weight increases with x³ while height only with x. Those are only very rough estimates, and the weight would also depend on the individual condition of the animal and the season. 

What is interesting now is that many domestic bulls surpass the possible weight of the largest aurochs. Bulls with a weight of over 1000kg are actually not a rarity in breeds of a medium height. For comparison, the Taurus bull Lucio had a withers height of 165 cm and a weight of 1400 kg. A 165 cm tall aurochs bull would, if the estimation above is correct, weigh around 500 kg. So the Taurus bull has more than twice the mass of an aurochs with the same height. That is due to the different morphology: domestic cattle mostly have shorter legs and a longer trunk, plus a smaller hump as much as a way bulkier trunk, especially the intestines are enlarged. This results in a higher weight relative to the withers height.  

Lucio the Taurus bull (Sayaguesa x Heck)

The morphology of cattle drastically changed during domestication: the legs became shorter, the trunk longer, the intestines larger, the head smaller, the hump smaller et cetera. This led to a dramatic height decrease, while the mass was not that much affected. Surely there are dwarf cattle breeds that are lighter in weight than the aurochs probably was, especially during the Bronze age there were tiny cattle that were about the size of a sheep. But as far as the average modern day cattle body size is concerned, cattle lost height during domestication but not necessarily mass. In some cases, mass was even gained compared to the aurochs. 

So, if mass would be the only parameter for body size, then most domestic cattle are not necessarily smaller than the aurochs, it is their morphology that changed dramatically. 

The dingo: a post-domestic wild animal?

Long-term readers of my blog will be familiar with my dedomestication hypothesis that I proposed in the dedomestication series. The term dedomestication is not very established in scientific literature yet, but there can be now doubt that natural selection will change domestic animals that have returned into the wild. This evolutionary process would result in what I call a post-domestic wildtype, opposed to a predomestic wildtype. This post-domestic wildtype would be just as wild as any other wild animal, with the difference that it descends from a domestic population. 

I proposed that this post-domestic wildtype is not necessarily a revert to the original predomestic wildtype, but that it depends on the selective pressures in the respective environment, genetic drift and also that novel traits can be beneficial, especially in a new environment. As I write in my dedomestication series, the hypothesis has empirical problems. For once, feral domestic animals are understudied in terms of possible evolutionary changes they experience. And moreover, there are hardly any feral domestic populations that have been living in the wild under natural selection for a considerable time span sufficient for evolutionary changes to become visible and at the same time reproductively isolated from backcrossing with wild or domestic animals. For example, feral pigs in North America (razorbacks) sometimes greatly resemble the Eurasian wild boar, what would endorse one of the main proposals of the dedomestication hypothesis (namely that wildtype traits tend to have a higher evolutionary fitness and thus the feral population starts to resemble the original wildtype on adaptive traits). The problem is, however, that these feral pigs often hybridized with wild boar that have been introduced there as well, what explains the resemblance between the two. 

Nevertheless, I see two possible candidates for a post-domestic wildtype because of a considerable time span they have been reproductively isolated and exposed to natural selection: the dingo and the European mufflon. This post is going to focus on the dingo. But first of all, it is essential to define which criteria an animal would have to fit if it was to be considered a post-domestic wildtype. 

 

A definition of the post-domestic wildtype

 

The most abstract definition of a post-domestic wild animal would be that its biology is entirely shaped by natural selection and not artificial selection. In detail, this would mean: 

- It is devoid of typical signs of domestication: paedomorphy in behaviour and morphology, earlier maturity, loss of seasonal adaptions, white spotted patterns in the colour or other detrimental colour mutations, reduced brain volume, reduced sexual dimorphism

- It is adapted to the biotic and abiotic factors of its environment 

- It is more or less homogeneous in its biology, especially regarding adaptive characters 

The exact time span of how long the animal has been subject to natural selection is technically of limited relevance, because the speed at which evolutionary changes become evident depends on how genetically diverse the starting gene pool is – this is known as Fisher’s fundamental theorem and it describes that changes in allele frequency occur faster in a very diverse population compared to one that is genetically homogeneous.

 

Is the dingo a dog at all and does it have domestic ancestry? 

 

A question which has to be investigated before is if it is true at all that the dingo has a domestic ancestry and if it is a dog at all. That question is relevant as there are some sources questioning the status of the dingo as a dog and prefer to regard it as a separate wild canid species that was never domesticated like coyotes and golden jackals. 

This idea, however, seems to be contradicted by the genetic evidence. Jackson et al. 2019 have reviewed several phylogenies based on genetic analyses and all of them have the dingo placed within the phylogenetic tree of the dog [1]. This strongly implies that the ancestors of the dingo were domestic dogs. One recent study from 2022 had the dingo as a sister group to all other dog breeds examined, but the number of dog breeds used was only six [2], therefore very low considering that there are hundreds of dog breeds. It was found that the dingo has only one copy of the AMY2B gene, which is multiplied in other dog breeds as an adaption to starch-rich diet [2]. That is, however, not an argument in favour of the idea that the dingo is a never domesticated wild canid, it just means that the duplication of the gene did not occur right at the beginning of dog domestication so that there are breeds that do not have it. That would be like claiming Sayaguesa cannot be domestic because it has the E⁺ allele, which is wildtype. The dog breeds that group with the dingo are, among others, the Chow Chow, the Akita, the Basenji and Indonesian and various Southeast Asian dogs [1,3]. Half of the dingoes tested in one study have the A29 mitochondrial haplotype (which is considered ancestral to all the other mitochondrial dingo haplotypes), which is also found in East Asian, Southeast Asian and American dogs as well as the New Guinea singing dog [4]. So from a genetic perspective, there can be no question that the dingo is a dog and shares domestic ancestors with other dogs. 

It is also morphological evidence that contradicts the idea that the dingo is a distinct, never domesticated wild canid species. Dingoes do have vestiges of domestication, including typically domestic traits such as a brain volume reduced by 30% compared to the grey wolf [5], reduced mimics and less social differentiation compared to the grey wolf [5,6], curly tails in some individuals [7] and cranial paedomorphy [8] and the males are able to reproduce all the year round [7]. Moreover, some dingoes have clearly domestic coat colour variants, such as brindle or white-spotted or piebald patterns. All these traits strongly suggest that the dingo is a dog, sharing domestic ancestors with other dog breeds. 

Also the behaviour of the dingo demonstrates that it is a dog – dingoes are sometimes kept as pet dogs, and already the Australian aboriginal people kept dingoes [9]. Alfred Brehm in Brehm’s Tierleben reported that there were dingoes kept as pet dogs and were used to protect livestock. Also, ethologist Eberhart Trumler studied dingoes kept as pet dogs and reported that they can even be made house-trained. Keeping a wild canine, be it a wolf, a coyote or jackal, as a pet dog this way would be impossible. 

Therefore, putting everything together, I think there is no reason to not assume that the dingo is a dog and shares domestic ancestors with other dog breeds. 

 

Does the dingo fit the definition of post-domestic? Is it wild or feral? 

 

My definition of post-domestic can be seen above, it has three key points. Without question the dingo is adapted to its Australian environment, it can make use of various food sources and it is adapted to the climate as the wide geographic range on the continent demonstrates. Concerning its morphology, the dingo seems to be uniform like a wild animal. Concerning its colours, they are more variable than what is commonly expected. A 2021 study found that because of the variation in the dingo’s coat colour, this parameter cannot be used to discern pure dingoes from hybrids with other, later arrived feral dogs [10]. Wild animals are usually – usually, not always – comparably uniform in colour across the species and the dingo coat colour variation is obviously a vestige of domestication. However, if the domestic coat colour variants found in the dingo (I consider all of the colours found in the dingo domestic, i.e. they arose after domestication, as none of them are the wildtype colours shared by wolves, the ancestors of dogs) turn out to be adaptive in the new environment they have been introduced to (Australia), they cannot be used as an argument against a possible wild status. If a novel trait that arose during domestication is adaptive in a new environment and becomes fixed, it would actually be in line with my dedomestication hypothesis. I never proposed that a feral domestic animal would fully revert to the original wildtype under natural selection, because some novel traits can be adaptive especially when the population lives in a new environment that is different from that of the original wildtype. In Australia, the colour of the dingo is likely better camouflage than that of the wolf in Asia where the dog was domesticated. Therefore, the colour of the dingo is likely adaptive. Perhaps some more millennia of dedomestication will eventually lead to a uniform colour, via stabilizing selection and genetic drift. Therefore, if a possible post-domestic animal has retained novel traits that arose during domestication, it still can fit the criteria for being a post-domestic wild animal as long as these novel traits are either adaptive or evolutionary neutral. But the dingo also has other remnant traits of its domestic ancestry as outlined above, some of which are part of the universal “domestication syndrome” and possibly maladaptive, including the reduced brain volume, cranial paedomorphy and curly tails in some individuals. Also, the fact that dingo males are able to reproduce all year round shows that they have not yet fully redeveloped a seasonal reproduction circle. Moreover, the fact that dingoes can be used and trained as pet dogs shows that the neurologic-endocrinologic modifications that turned dogs into domestic animals are still present in the dingo, and that it has not yet lost the potential to develop domestic behaviour. To me, this suggests that the dingo should not be considered a post-domestic wild animal. 

It is problematic, however, to draw a distinctive line between feral and post-domestic wild. Rather it should be regarded as a continuum, as a spectrum. The dingo definitely is on this spectrum, but in my opinion still closer to feral than to post-domestic wild. Interestingly, there also seems to be a continuum from other basal dogs to the dingo, as Southeast Asian pariah dogs, Borneo dogs, the Korean Jindu and the American Carolina dog are phenotypically very similar to dingoes. All of them, including the dingo, can be kept as pets. 

 

An upcoming post is going to focus on the European mufflon as a post-domestic wild animal candidate.

 

Literature

 

[1] Jackson et al.: The Dogma of Dingoes – Taxonomic status of the dingo: A reply to Smith et al.. 2019.

[2] Field et al.: The Australian dingo is an early offshoot of modern breed dogs. 2022.

[3] Larson et al.: Rethinking dog domestication by integrating genetics, archeology, and biogeography. 2012. 

[4] Savolainen et al.: A detailed picture of the origin of the Australian dingo, obtained from the study of mitochondrial DNA. 2004. 

[5] Hemmer: Domestikation, Verarmung der Merkwelt. 1983 

[6] Trumler: Ein Hund wird geboren: der Ratgeber für den Hundefreund. 1982. 

[7] Zimen: Der Hund – Abstammung – Verhalten – Mensch und Hund. 1988. 

[8] Smith et al.: Brain size/body weight in the dingo (Canis dingo): comparisons with domestic and wild canids. 2017. 

[9] Roland Breckwoldt: The dingo: still a very elegant animal. In: A symposium on the dingo. 2001. 

[10] Cairns et al.: Pelage variation in dingoes across southeastern Australia: implications for conservation and management. 2021. 

 

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.