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Saturday, 4 January 2014

New Aurochs head reconstruction and new photo from Oostvaardersplassen

One week ago, I found a photo of a Brown Swiss x Holstein cross: 


©Norman Walker
Nothing of interest for breeding-back of course, but I found the skull shape rather interesting and thought of the Cambridge cow (or: putative cow), which's skull is not as elongated as in most other aurochs specimen though (there are not-as-long-snouted bulls as well, but such individuals are not very common in the record). So I superimposed the Camebridge skull on that cow's head, and found a perfect match - only the frontals of that cow are totally underdeveloped, because it has very tiny (or not even any?) horns. 

This inspired me to do an anatomically reliable reconstruction of the Camebridge cow's head: 
All rights reserved; please mention me if you want to use it. 
The cow isn't necessarily supposed to be black, in many aurochs-coloured cows the head and neck is black but the back is still reddish-brown. The surprise of that cow's head is that it looks quite similar to that of some domestic cows, so that breeding-back does not have to select for hyper-longsnouted cows exclusively. However a straight to convex snout profile should be obligatory. 

Moving to another snout-based issue, I recently found a photo from 2009 of a Heck herd at Oostvaardersplassen on the Wikimedia Commons: 

Taking a closer look, you will realize that some of the cows are rather long-snouted, much more than any Heck cattle outside the reserve and even more than many Taurus cows. This is impressing. It is not the product of artificial but pure natural selection. It is also surprising that this herd is composed of aurochs-coloured individuals exclusively, except that one calf with the white spot on its head - it could be a coincidence, but in the past Oostvaardersplassen had a high portion of grayish, steppe-cattle like individuals because of the bad quality of the founding herds. Now it seems that the number of aurochs-coloured cattle is increasing. How comes that, in the absence of predators, and what's the selective advantage of a long snout? 



I think that we see pleiotropic effects here. The farm fox experiment (more on that in a future post) has shown that selection for tameness in domestication also caused new, deviant features common in all domestic animals (white spots and paedomorphy for example). Now, with the cattle being exposed to natural selection for 30 years, I think natural selection favoured any genes that increase the fitness of the individuals, f.e. regulating behavioural aspects, such as dominant behaviour, feistiness etc. These genes might also result in traits seen in the wild-type (aurochs) which have been altered by the usual domestication process. So natural selection can redevelop wild traits even if that particular trait does not have an immediately visible selective advantage, probably even better than artificial selection. 

It is really a shame that the dedomestication taking place at Oostvaardersplassen is so horrendously understudied. We are witnessing evolution at work, guys! If a long-term dedomestication study would be started, this population probably will be a prime schoolbook example for an evolutional process. 

15 comments:

  1. So I'm not alone in my belief that the Silver Fox experiment selecting for tameness also caused morphological changes to the foxes? On the forum I never gotten any response when I brought that subject up, other than one member's imaginary scenario why it isn't correct.
    If the herd is indeed changing to more aurochs like animals on their own, then we don't really need to worry about influencing herd genetics.

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    1. Yes, the view that selecting for tameness is supported by peer-reviewed papers. I'll do a post on the farm fox experiment when I have the time to research a little deeper into it.
      The herd seems to become more aurochs-like and it is fascinating to watch that; I think it is a matter of opinion if you prefer some selective culling and import of more aurochs-like animals to speed up the process (what would adulterate the impact of dedomestication), or just watch how long it takes until the animals look like small versions of the aurochs. I'm not sure what I would prefer, both scenarios are awesome. The worst would be if the Tauros people convince the Staatsbosbeher to remove the animals, it would ruin this fascinating dedomestication process.

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  2. Did you notice what appears to be a bull, on the left side, in that Oostvaardersplassen photo?
    Black coat, and forelocks, and darkened mealy mouth.

    Link to the animal I'm referring to:
    http://oi44.tinypic.com/xkrh2a.jpg

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    1. Yep, I noticed him already. The colour is good, but the horns still face quite outwards; strangely the horn curvature seems to adapt faster in cows than in bulls.

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  3. the original brown swiss (brune suisse) are really nice cows, they are used as crosses with holstein for better legs and feet - unfortunately i believe they have now been infused with the polled-gene, which prohibits the growth of horns, to farmers a positive trait in function of human (and animal) safety but in the light of capacity to survival a nono.
    But i believe they have a dilution of the red pigment and a change of black pigment to brown (chocolate)
    In case of the brown african cow in a former blog, that could be due to severe lack of certain vitamins that can bleach black

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    1. I looked for some good cows of the brown swiss on google, most of them were pretty massive and had a large udder but cows like this one (http://www.tiroler-braunvieh.at/uploads/pics/Brown_Swiss_Championat_001.jpg) look nice indeed! I also found this cow (http://i734.photobucket.com/albums/ww345/basil-seal/2011_0727picsforsorting0059.jpg) which was presented in a forum as a cross of "holstein, brown swiss and shorthorn". The colour isn't bad, and the long snout is very aurochs-like.
      I'm not sure if a lack of vitamins is a sufficient explanation for this weird brown colour in that Sanga cow, because related cattle show a very similar colour also on other grounds and locations (f.e. Europe, USA), I am thinking of Watussi for example.

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  4. The conclusion from Belyaev`s Foxes are controversial although I am not sure if there are any paper published about that.

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  5. The longer head could be an adaptation for better grazing/browsing in that area.They do look abit skinny,maybe the food quality is not the best and they have to adapt to that?

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  6. A grazing adaption was my first explanation for the longer skull, but I don't know that should make sense. And it wouldn't explain why the snout doesn't only get longer but also looks more "adult" - smaller eyes, straight/slightly convex snout profile.
    They don't appear skinny to me, and if they are, the problem is more likely related to the size of the area and the population density, since they previously thrived in the reserve.

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  7. Looking at the earlier photos of this herd that you posted .The cattle appears to developing into a lighter more athletic type ,some look a bit thin .If this is an adaptation to the nutrients or if is due to a strong competion among bulls behind what appears to be a genetic adaptation is a good question.Are there no human selection at all on this herd?It is hard to understand why the colors would be changing without selection pressure from human or predators..

    Any way thank you for a a great blog and all your interesting posts at the carnivora forum!

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    1. Thank you!
      Well, I think that both the environment and genetics influence the body shape of Heck cattle, like in basically any tetrapod. And I am sure that natural selection caused a change in the genetic makeup controlling the body shape, and that athletic bulls won't revert back to a domestic, fat body if they were raised in a zoo or something, although they would be heavier than their wild counterparts, like any wild bovine.
      There is no artificial selection in Oostvaardersplassen, only very weak cattle are culled during winter to prevent suffering, like deer. There are many reasons that can change the colour. First of all, unpigmented areas, or simply less pigmented areas (dilution), increase the cancer risk because more UV radiation is absorbed. Furthermore, there are, like I explained in the post, evidently pleiotropic effects, such as Thyroxinase which is responsible for the production of melanin but also has other functions in the body (but I am amateur on this subject). And last but not least, sexual selection is important. Animals with a shiny red/black colour might be preferred over tan or sallow-coloured animals. Therefore, it is absolutely not surprising that the colour will change when the cattle are released into nature, but the speed at which the first small changes are visible surprised me.

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  8. Considering the hormone-driven growth differences, they should maybe set up a different project in which they artificially give calves different (stress)hormones (f.i. thyroxinase) and see if they develop an adult-type face en colour,. Would be quite unethical, but interesting.

    In the recent and very succesfull cinemaversion of the documentary 'de Nieuwe Wildernis' heckcattle played no role at all (probably because of the ethical problems the OVP-experiment has been giving and the domestic outlook of many of the heck-cattle there). In the longer version, that was broadcast on dutch television in three parts, you can see an interesting item on a fight between two bulls, both of which show a number of aurochs-features. Maybe you can still download it somewhere.

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    1. Hi, yes, I've seen the shortened version on Youtube and was quite upset about the absence of Heck cattle. But today I ordered the full version on amazon, if there's anything interesting I'll report it here.

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  9. Unfortunately that's the cinematic version as well, so no Heck catlle there either. The footage I'm talking about was only broadcast on tv and had a different voice-over as well. Perhaps they added it to the second dvd as an extra. Even still, the other wildlife is spectacular enough in itself and gives a small glimpse of how a large nature reserve with bred-back large grazers might function in the future.

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  10. As an afterthought, I see that it is possible to order the television-series through the networkwebsite (VARA) as well. Quite costly though and only in dutch. Here is the link:

    http://shop.vara.nl/de-nieuwe-wildernis-dvd-box

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