The looks vs behaviour problem and the Spanish fighting bull

In the post Cattle are modified designer aurochs I explained how “cattle” is just a term for an aurochs that has been modified by millennia of domesticative breeding.  I used Maronesa, Fleckvieh and Heck bulls as examples. Despite an overall similarity that Maronesa and Heck cattle bear to the aurochs, most of the differences between aurochs and cattle apply in both cases. For this post, I want to analyse the Lidia breed, Iberian fighting cattle, in the same way. In case you haven’t read both posts that I just linked here yet I would recommend to have a quick read through them before you continue with this post. The references for the claims below are provided in those articles. 

Changes from aurochs to Lidia 

 

Two comparably aurochs-like Lidia bulls on Wikimedia commons

The most obvious change from aurochs to Lidia is size. Size is on the one hand probably influenced by endocrinology (as hypothyreodic rats demonstrate) but also by mutations on the dozens, hundreds or even thousands of loci that regulate body size in mammals. Typically for domestic cattle, Lidia have reduced limb size, skull size and brain volume compared to the aurochs, which is probably linked to thyroid hormone activity (see my post above). However, Lidia is remarkable for being the one cattle breed on this world that still has an extremely wild cattle-like body morphology until a certain age. Young Lidia bulls have a slim waist with a much smaller belly than most domestic cattle and strong muscling that looks natural and not exaggerated as in meat breeds. Also, Lidia is the breed that has the largest hump (formed by processus spinosi) that is often only slightly smaller or as large as in the aurochs and also present in many cows. This remarkably aurochs-like morphology is probably also caused by the thyroid hormone activity as distortions of these hormones cause the classic domestic cattle morphology. In this respect, young Lidia are probably less-derived in this respect and have a more aurochs-like thyroid hormone activity with the developmental cascades linked to it. From a certain age, Lidia bulls, however, grow rather heavy. The hump becomes elongate and the body heavy and sausage-like. So probably at this certain point in development, the endocrinological activity shifts from a more aurochs-like condition to the domestic cattle-like condition we see in more derived breeds. The corticosteroid level of most domestic animals is reduced compared to the wildtype, resulting in the reduced fight/flight reaction we have in domestic animals. Lidia, however, was bred for a more extreme fight/flight reaction and this is what we see very clearly in its behaviour, so it would be interesting if the corticosteroid level in this breed is higher than in other domestic breeds. We have no living aurochs to compare with, it would be even more interesting if the corticosteroid level is higher than in wild aurochs or if it still is lower. 

The skull shape of Lidia is variable. Many Lidia have a shortened domestic cattle skull, but there are also many individuals, both bulls and cows, that have a skull shape that looks identical to that of the aurochs with a very elongate snout, a straight or slightly convex profile and small eyes. The extent of paedomorphy is linked to developmental delay, and apparently in these individuals the developmental delay for the genes responsible for skull shape is not that intense or not present. The horn shape of Lidia is reminiscent to that of the aurochs, also with an inwards curve. However in most if not all individuals, the curvature is too simple and banana-like. We might have a similar case as with the Taurus bull Latino (which was quarter Lidia, by the way) where probably only a developmental delay caused the reduced horn curvature and length and not a true change in the responsible genes (personal suspicion, see the post). 

So the changes in size, morphology, proportions, skull and horn shape and behaviour that we see in Lidia are probably caused by endocrinology and development, and also a few mutations, and all of these changes are probably less intense than in other domestic breeds, hence the primitive morphology. Looking at the comparison between a hypothyroidic rat and a wildtype, a hypothyroidic aurochs would probably look a lot like Lidia.* 

* It would be a very interesting test for this whole hypothesis, then, if Lidia that have a higher activity of thyroid hormones develop a more aurochs-like morphology.  

The colour of Lidia is variable, but most individuals have a wildtype colouration or the black mutation E^d(there are many additional variants however, including roan, grullo and also individuals carrying the alleles for spotting). In the wildtype coloured individuals, the genetic make-up responsible for the colour genes (which also regulate other factors of the organism, see the post above) is probably the same as in the aurochs. The sexual dichromatism is, however, reduced – many bulls have a colour saddle or are cow-coloured, while there are also a lot of very dark-coloured cows. Perhaps developmental delay alone is the cause of the reduced sexual dimorphism, maybe also mutations that regulate the sensitivity of the colour alleles to testosterone level (which determinates the colour difference between the sexes). 

The size of appendages (scrotum, dewlap and others) and udder is variable. In some individuals they are not enlarged at all. Lidia also often have prominent forelocks and curly hair on their face and neck/shoulder region which are most likely primitive traits (see forelocks and manes). Actually, many Lidia simply look like small, short-legged aurochs with shorter horns to me. They simply line up with the evidence for the aurochs’ external appearance to a large extent (see here). 

The aggression issue. All in all I think that Lidia is in fact one of the least-derived cattle breeds on this world. There are many who argue against a primitive status for Lidia because the aggression level of this breed is “unnatural”. This argument is weak as a) we have no living aurochs to compare with and b) the docility, tamability and trainability of other breeds can barely be considered the wildtype state either. We have to assume that the aggression level of the aurochs was comparable to that of other wild bovines. Wisent and bison, for example, are known to often attack without prior aggression display and also cape buffaloes and wild water buffaloes are known to be rather aggressive. Furthermore, historic accounts (such as Caesar’s De Bello Gallico or Schneebergers report in Gesner) suggest that the aurochs were might become very hot-tempered and aggressive if teased or threatened. It was a wild animal after all and we should make no illusions about its aggression level. I do not, however, rule out that the aggression level displayed by Lidia is intensified compared to the wildtype, just as in aggressive dog breeds. This, however, does not make it any more unnatural than gentle, docile and friendly breeds. Perhaps even the contrary – it seems that behaviour and morphology are tightly connected and the farm fox experiment has shown that selection on tameness does result in morphological changes while selection on aggression did not (see the Dedomestication series). And actually, I think that the energetic but nervous/aggressive behaviour of Lidia is more similar to that of the aurochs or any wild bovine than that of lethargic, docile, agreeable and gentle breeds. 

A very puzzling question is, then, if the primitive morphology is a primary or a secondary condition. The Lidia breed was created during the 18^thand 19^thcentury by breeding rural cattle for aggression under rather natural circumstances by continuously choosing the most aggressive bulls and cows for breeding. It would be interesting if these rural primitive cattle that were the ancestors of Lidia still had the primitive morphology modern Lidia have and their descendants kept it because they were only bred for aggression and agility and not for milk and meat as other breeds, or if their ancestors were comparable to modern Iberian landraces in morphology and it was the selection for aggression and agility that made them re-develop their primitive anatomy secondarily by pleiotropy and developmental cascades. This opens the second big issue of this post. 

The looks/behaviour problem 

The farm fox experiment was revolutionary for the understanding of the processes underlying domestication as much as the phenotypic changes that occur in all domestic mammals in the same way (“the domestication syndrome”). Selection on tameness alone produced typically domestic traits (such as changes in morphology and colour, paedomorphy, earlier maturity) in few generations while a group of foxes bred for aggression as much as the control group exhibited none of these changes. It proved that there is a tight interconnection between morphology and behaviour (for details details see articles already linked, or here). Most domestic cattle are perfect examples for that: tame and domestic behaviour plus domestic morphology. Lidia seems to be the reverse example: aggressive behaviour plus a much more wildtype-like morphology. 

These phenomena of course provoke the question if it is actually impossible to breed for an aurochs-like morphology in “breeding-back” without having the cattle without achieving a wild cattle-like behaviour at the same time. Maybe a long-legged, athletic, long-snouted bull or cow that truly is shaped and coloured like an aurochs but still is more or less tameable, relaxed and not explosive is a contradiction in itself. 

But at first we have to resolve what “aggressive” means and what we have to expect an aurochs to have behaved like. Many people, especially those involved in rewilding projects, claim that an aurochs was not an aggressive animal – this is, however, a matter of definition. For once, it is a fact that it was a wild animal and thus its fight/flight reaction was definitely more extreme than that of its domestic variants. This is the case in any species that was domesticated. And furthermore, I see no reason to conclude that it was less or more aggressive than other wild bovines. All wild bovines, be it bison, Bosor buffaloes, are known to actively defend themselves by attacking when they feel threatened, some with prior aggression display, some without. The aurochs must have been the same in this respect. Historic references document that the aurochs had the potential to become very hot-tempered, destructive and will attack humans as much as their animals (horses, dogs) if teased or threatened. This is what is to be expected from a wild bovine such as the aurochs. However, all wild bovines will prefer flight over attack if they can, cows with less mobile calves probably being an exception. In any case, you probably could not handle aurochs the same way as cattle. They surely were not as tameable, docile, agreeable and relaxed. No wild bovine is. You would have to expect an aurochs to be way shier, explosive, stubborn and panicking in stress situations such as narcotization, being tattered, transported or handled in any other way. And of course more willing to attack. Wild bovines are way more difficult, dangerous and expensive to handle and so would an aurochs be as well. And of course, a true aurochs would also be more dangerous and less tame to visitors in a reserve. One should not dream any illusions of aurochs being easy and harmless to handle. They were wild bovines and probably behaved the same as other wild bovines do. 

Primitive cattle are already difficult to handle under natural circumstances and an aurochs would be even more problematic. People who have to handle cattle in grazing and rewilding projects know that of course and I am convinced that nobody wants his cattle to react like a true aurochs would. Thus, what breeding projects want is cattle that look like the aurochs but do not behave like the aurochs because the way those are kept in grazing projects and rewilding projects does not allow that. 

There have been plenty of individuals in “breeding-back” projects that actually had a good looks but a behaviour that made them problematic because they were too nervous or explosive to handle them without danger (what does not necessarily mean that they were “unnaturally aggressive”, not at all). Examples are, for example, the Taurus bull Toldi in Hungary or the cow Leier at the Lippeaue – both of them did not have any Lidia in their ancestry. They were difficult to handle, but probably still less problematic than an aurochs or any other wild bovine. 

It will be absolutely possible to breed for aurochs-like cattle with the right size, right horn dimensions and curvature, right colour setting, some degree of sexual dimorphism, comparably long legs, a skull shape that is at least not paedomorphic and a body that is comparably lean and muscular and not heavy and tube-shaped. But it might be questionable if it is possible to breed for a wonderfully aurochs-like physique with an athletic slender waist, tight body, a well-pronounced hump and a skull shape that matches that of the aurochs with an elongated, straight or slightly convex profile and small eyes in the conventional way because of the complicated interconnections of development, neurology, endocrinology and other factors. In foxes, for example, conscious breeding for earlier maturity and larger litter size was unsuccessful, while selection on tameness resulted in exactly that₁. 

A reverse test: selection for wildtype behaviour

This brings me to the next question: would we actually have to select “breeding-back” results for a more intense fight/flight reaction, shyness, explosiveness and other wildtype behaviour traits in order to reverse the morphological modifications of domestication? I consider it possible that this might be true. It would be worth a try but would take a while until results can be judged in such a slow-reproducing species as cattle and it would probably not be possible to execute such an experiment under the frame of a grazing or rewilding project because of the way the cattle have to be handled. One would have to keep them the way Lidia cattle or wild bovines are handled. Such an experiment would be very tempting and might produce interesting results. It would be the reverse test to the Farm fox experiment and would, if successful, provide another strong argument for the interconnection of behaviour and morphology. 

If you would consider the results of such a project not suitable for rewilding anymore because of their wilder behaviour, you probably would also have to consider a genuine aurochs and also the wisent not suitable for modern Europe. It is just a matter of how much space you have and how you have to handle the animals. 

Literature 

1 L. Trut: Early canid domestication: The farm fox experiment. American Scientist. 1999.