My readers will know that I focus a lot on morphological and other visible traits on my blog. Therefore I am sometimes asked how much authenticity in regards to optical traits is needed at all – if a good cow has some white spots, or if the population shows a lot of colour variants and horn shapes, who cares as long as the animals do well in nature? But more importantly, do I focus too much on optical traits?
Isn’t it actually more important that the cattle are resistant against diseases, can live in nature without medical care, do not need calving assistance, show natural instincts such as herding et cetera, know how to defend themselves against predators, are suited to the climate of the reserve they are released in and are able also to cope with harsh conditions and low nutritional food and should not genetic diversity always be a priority for the populations?
|Tiny white spots on an otherwise very good Taurus cow: dramatic? Photo by Matthias Scharf|
Yes, of course these traits are the most important when you want to release the cattle into nature as part of an ecosystem. But the thing is that we can be rather sure that those traits named above are universal for the primitive landraces used in the projects because they not only look aurochs-like but are less-derived overall, and since they have been spared from overbreeding for high productivity it would be new to me if any of the breeds used is prone to a certain disease, sensitive to harsh conditions or would not show natural instincts in the way described for other breeds (f.e. see this work on the social system of Galloways, which is comparable to that of wild bovines, or Poettinger 2011 on Heck cattle compared to wisent). Of the breeds currently used, I know that at least Maronesa is used to deal with wolves in the region the Tauros Project got their individuals from, and I doubt that other primitive landraces would be helpless around wolves, or know less good how to defend themselves against predators than derived breeds. And even derived cattle do have the natural instincts to defend themselves against predators. Apart from that, landraces have no history of being separated from harsh climate conditions or not having to deal with the low nutritional food their surroundings provide, otherwise they would not be landraces.
Furthermore, we have a lot of feral cattle populations all over the world that established themselves in a lot of different habitats without human help, and these often descended from usual farm cattle and not particularly primitive landraces.
For genetic diversity, the right balance has to be found between creating a physically more or less homogeneous and genetically diverse population. It is a kind of balancing act but all of the projects are aware of the importance of genetic diversity.
So I think there are good reasons to assume that those vital traits named above are always in the package when using primitive, less derived healthy landraces that have to deal with harsh conditions – which is the case in all “breeding-back” projects. This is why you hear that few about it on this blog. Of course this does not mean that any of the projects should stop caring about these traits – stopping to care about traits bears the danger of having these traits reduced in the long run (this phenomenon is called relaxed selection). But I don’t have the impression that any of the projects neglects the hardiness, health and genetic diversity of their populations.
Which brings us to the next point: how much should we actually care about optical traits? How much resemblance is “enough”, and can “imperfections” (f.e. such as tiny white spots on the belly) be considered trivial?
This is of course a very good question. The first priority, in my opinion, concerns the evolutionary fitness of the animals themselves. It should be as good as possible, so let us have a look at how crucial the traits that breeding-back projects care about are for survival. I already explained that visible traits, therefore size, morphology, coat colour et cetera do have a more or less big influence on the evolutionary fitness of the individuals themselves and the population as a whole in the Dedomestication series. But I am going to sum up why the aurochs-like traits we want in “breeding-back” have an evolutionary advantage:
- Size: the bigger the better cattle can defend themselves and their offspring from predators. Also, large bulls have a direct fitness advantage over a bull of the same morphology of smaller size in mating fights.
- Morphology: cattle with long legs, a slender waist, high processus spinosi resulting in a hump and a muscular and not bulky body (short: the morphology shared by all wild bovines) are faster, more swift and agile and therefore have a direct fitness advantageous over bulky, short-legged and sluggish cattle in defending themselves against predators or intraspecific competition
- Horn shape: The horn shape of the aurochs was functional and not arbitrary. It was advantageous in intraspecific competition by making it easiest to pull, push and drag the opponent (see this post). Other bovines that fight in a similar manner have the same horn shape (yak, kouprey), and even the tusks of mammoth have the same curvature if you look at them standing on your head.
- Colour: spotted calves likely are more prone to get discovered by predators when lying hidden in the bushes as they usually do during the first days. Also, some colour alleles are known to be linked with a risk of cancer because of the reduced melanisation (see the Dedomestication articles). There might be more such pleiotropic effects.
- Appendages: A short dewlap and small furry udder mean less heat loss than large dewlaps and udders, which is advantageous in winter.
- Sexual dimorphism: sexual dimorphism is the result of the mating system in any species. In cattle, it lead to bulls being way bigger than the cows and both sexes being of a different colour. Competition and female choice therefore favour certain sizes and colours.
However, one might argue that traits that give individuals an intraspecific selective advantage will not have an influence on the survival abilities of the population as a whole, and that is correct. For example, the horn shape of the aurochs was surely advantageous in intraspecific respect, but if all the cattle in the population have deviant horn shapes it does not decrease their evolutional fitness as long as the horns are formidable enough to fight off predators. Or take traits that give a selective advantage for female choice: the number of calves born will not be altered if bulls have different selective success.
So O.K., then let us say all the traits that increase individual fitness only in intraspecific regards does not matter that much for the survival chance of the population as a whole. The other traits will become reinforced or redeveloped by natural selection if they truly serve a purpose anyway, so why caring about them? Especially coat colour has the least effect on the fitness of large animals and sometimes the colour of large herbivores are likely to be the result of mutation and genetic drift – for example, would not the Malayan Tapir be equally camouflaged or even better if it was coloured like its extant relatives and not like a panda*? Or the shiny-red African forest buffalo? And just see the interesting colour variants that appear in wild populations of Plains zebra (here) and wildebeest (here and here). So for colour, the room for possibilities is obviously bigger than the narrow space the confirmed European aurochs colours give us. For example, wouldn’t an aurochs with the colour of this impressive Lidia bull at 5:16 (which is probably the colour variant called “Grullo” caused by the Ds allele on black base colour) be quite well-camouflaged in the landscape of Southern Europe?
As for advantageous morphological traits, if we assume they are evolutionary advantageous and therefore inevitably evolve in a feral population, why should it be necessary to breed for them? Furthermore, large size must not necessarily be a fitness advantage in modern Europe. The last aurochs seemingly decreased in body size due to habitat disruption and limited food availability, and the habitat of the “breeding-back” results would be limited reserves, and therefore dispatched small islands in the ecological sense. And as everybody knows, the island effect tends to shrink down the size of large vertebrates as a result of limited space and food availability. Why breeding for large size then? Breeding smaller cattle would be advantageous for them in the long run, and you could even introduce more individuals in the reserve at a certain point (f.e. if there is a reserve where there is food supply for 200 cattle of 600kg, it means that there is place for 120.000kg of cattle, which, in turn, means that there would be food supply for 300 cattle weighing 400kg), and larger populations mean a higher likelihood for survival. Therefore, maybe nobody needs large aurochs in the Europe of the 21st century. Maybe its time for small aurochs.
* I cannot rule out that the exceptional colour of this tapir species has some selective advantage that is not apparent at first glance. It is just an example.
So why not simply tossing a heterogeneous bunch of cattle of usual or even small size that show the vital ecological and behavioural characteristics that all landraces do into the wilderness and see what happens? At least they would show the ecologic capacity to survive the climate and can live on the natural food supply, do not need medical assistance and so on. And if certain aurochs-like morphological traits would be advantageous, they would develop anyway. So why making the extra effort of breeding for them?
Actually, it increases the likelihood of survival for the population if the aurochs-like traits that are advantageous were already widespread or universal in the population. For example, if half of the cattle, or even all of the cattle, are short-legged, massive and sluggish, they would have a much higher risk of being killed by predators and not defending their offspring successfully, while that risk would be way lower in a population of cattle that already are universally large, long-legged, swift and agile. That also goes for small-sized appendages like udders and dewlaps: if you do not care about these traits in the cattle you are releasing, a number of individuals will have more heat loss and therefore less evolutional fitness than cattle that are aurochs-like in these respects.
Thus, many visible traits do probably have a considerable influence on the evolutional fitness of the cattle, which is why we should care about these traits as well in order to increase the likelihood of survival of the population as a whole.
Regarding the size, the island effect is a tricky argument at first. Indeed I think it would serve no real good trying to counteract the trend if a feral cattle population does become smaller. For example, I would not be surprised if many of the bulls of the isolated population at Oostvaardersplassen are below the 140cm mark already. But for the future, I hope that there will not be dozens of reproductively isolated islands of aurochs-like cattle but one big, qualitative European metapopulation of aurochs-like cattle. In this case the island effect would be much smaller. Furthermore, should we breed wisents for smaller sizes so that we can release them in higher numbers? Or elks? Yes, the last centuries were bad centuries for large animals, and the 21st is probably the worst, but that does not mean that we have to shrink them down. If we want to conserve them, we have to conserve them in all their biological integrity.
The next point are public relations. It is important to communicate the cattle as a proxy for a wild animal that at some point will be wild animals. Otherwise any projects that involve a true dedomestication of these animals (which is the goal of the Tauros Project or Rewilding Europe) will constantly face critique and public outcries (“oh you can’t let those cute calves starve like that, that’s animal cruelty” – no, it’s not, it is nature, thousands of deer starve each winter and nobody on earth cares since it is regarded as natural). So you have to successfully communicate that those animals are part of nature now, and this works best if the animals also have the looks of wild animals.
Why does it work so well to sell Exmoor Ponies and Koniks as wild horses or nearly wild horses? Both breeds have been actively bred for homogeneous looks (yes, it is evidently proven that they look homogeneous because they were bred for it and that the modern versions of those breeds are actually an invention of the 20th century; for details on the breeding history of the Konik go here, for the Exmoor here), and people are smart enough to know that wild animals are usually very homogenous in looks while domestic animals display a huge variety of morphology and coat colour. So if you want to communicate a population of cattle as a part of nature, it would be best if this population is as homogeneous as possible (of course at the same time keeping it genetically diverse) and nearly impossible if the population is heterogeneous in morphology and colour. That’s why New Forest ponies and Dartmoor ponies are not sold as “wild horses” which cannot deny their domestic ancestry due to their heterogeneous appearance (ironically, in the case of European wild horses there were seemingly more than one colour variant, see here). White spots in particular literally scream "domestic".
The cattle should also show the physique of wild animal and a minimum of paedomorphic traits that reveal them as domestic animals. When I got into the aurochs in 2011, and knew only about Heck cattle but not primitive landraces, I was enchanted by how some lineages achieved an aurochs-like colour scheme or impressive horns, but there was always something that kept me from regarding them as phenotypically “reconstructed aurochs”. Something just did not match. When I then discovered all those Southern European landraces with their far less derived morphology and head shape, I realized that it was the usually totally domestic morphology and calf-like faces of Heck cattle that distracted me and made them look a) like domestic animals (what they and all other “breeding-back” results are) and b) “just like any cow” with special colour and horns. And I think it is likely that most people are educated and intuitive enough to tell the body shape of a domestic and a wild animal apart, even if you probably will not hear the explanation “well, the cattle lack high processus spinosi in the shoulder region and the skull shows paedomorphic traits, therefore what you call wild cattle here are clearly domestic animals” from Mr. Everyman who visits a reserve or zoo.
Furthermore, it is advantageous if the cattle make an impressive sight, for touristic and other PR reasons. And the aurochs was a very impressive sight. A large bull with aurochs-like proportions, that moves fast and energetic and is swift and agile will leave a much bigger impression on a visitor than a 140cm bull that looks tired and bored and moves sedate. Not to mention the impressive, elegantly curved large horns. A more or less uniform horn shape that points forwards would certainly be more attractive than horns just pointing anywhere. Apart from that, the colour scheme of the aurochs was very aesthetic. The rich and strong colours, the powerful contrasts of the light markings on the dark base colour, the shiny red of the cows and the deep black of the bulls – a colour scheme that is probably way more eye-catching than just dull brown (not to offend the wisent of course, which is also an extremely impressive animal). Especially fascinating would be the strongly marked sexual dichromatism which is virtually a bovid speciality among mammals (while not that rare in sauropsids) and definitely a wild animal trait. I know that when I was a 8-year-old kid the colour difference between the sexes in the aurochs fascinated me and I kept it in my memory for all those years.
What brings me to the next point: Authenticity. Personally, I want authenticity. It has always been my dream being able to see extinct animals living and in flesh, and in the case of the aurochs, it is possible to see something that comes at least very close. And better than that, it is even possible to restore its ecological niche on its former range using those authentic cattle, with benefits for a lot of other species. So why not grabbing this wonderful opportunity? That’s why I want authenticity, I do not want to have “wild cattle” running around in grullo, roan, spotted or any domestic colours with meagre horns pointing anywhere, for the same reasons I do want wisents to be reintroduced in Europe and not wood bison which would do just as well here. We can achieve a large degree of authenticity, and I want authenticity. And a lot of other people want it too. Enough people so that they started “breeding-back” projects which are all on a good way now, and in sum achieved hundreds of aurochs-like cattle. If you personally don’t want that authenticity, it is up to you, but then it seems like you are not interested in “breeding-back”.
All in all I would say that there are good reasons to breed for a maximum of feasible authenticity, and as long there are many other people who have a passion for that (and I suspect the numbers are rising), there are projects doing so. It will be beneficial for people interested in extinct animals like me, nature enthusiasts and the cattle themselves.