Thursday, 25 April 2019

Aurochs model: Horns & finish

The shape of my aurochs model made from air-drying clay is finally finished and ready to be painted. I added the curly hair (the mane and forelocks) and the horns. Adding the horns was a crucial and fun step as they are quite an important part of an aurochs' life appearance. 

The reference specimen for the horn shape and size were the Sassenberg, Berlin, London and Baikal specimen. I checked each millimeter, so the dimensions should be correct. At first, I sculpted the bony cores as they are in the original skulls. I started by adding wire of the right size and curvature: 
Then, I started to sculpt the "horn core": 

If you look at fossil skulls, I would say those horns turned out to be very accurate
Before sculpting the "horn sheaths" I painted the horns with red acrylic colour, in order to distinguish them from the new material. The angle of the horn cores to the snout is exactly 65°, which is within the average for northern Eurasian aurochs (Sassenberg: 65°, Lund 60°, Kopenhagen 50°, Vig 85-90°, London 70°, Berlin 70°(?), Baikal 70°; deduced from photos). 
Then, I added the horn tips which would add about 30% to the length (average, but there is great variation) by following the curvature:
After that, I added the thickness of the sheath. As original aurochs horn sheaths are known to have added about 1-2cm in thickness to the bony core, it would be about 2-3mm in the model, which is what I did: 
Then, I completed the shape: 
And sanded it with sandpaper: 

The result resembles the horns of wild yak greatly, which have horns nearly identical to those of aurochs. I think about adding a bit to the thickness of the horns, looking at live yaks and preserved horn sheaths. 

This is what the (nearly) finished model looks like at the moment. I will start painting it as soon as I can: 
The head and horns look a bit huge due to perspective, by the way. 

Sunday, 14 April 2019

Auerrind herd at Groß-Rohrheim

Two days ago, a couple of new recent photos of the Auerrind herd at Groß-Rohrheim, Germany, were published on the Auerrind Project's blog: 
The white individual in the background is a pure Chianina cow, the two next to it are two Sayaguesa x Chianina (the blogpost doesn't specify the sex, but they might both be female). In the front at the left, there is the Sayaguesa x Grey cattle cow plus the Watussi x Maremmana heifer. 
The Sayaguesa x Chianina individuals seem to have a quite well-shaped anatomy and good size, I am looking forward to see them as adults, and especially F2 of this generation. 
This is the Watussi x Maremmana heifer. The colour seems to be perfect (phenotypically, it surely is heterozygous for recessive colour dilution genes), the horns are probably going to develop a nice volume. The curvature most likely will be rather straight and upright, but this is to be expected from this combination and can be fixed in later generations. A (Watussi x Maremmana) x (Sayaguesa x Chianina) would be tempting, more efficiently in the form of an F2 x F2 combination. 

It is nice to see that the Auerrind project is still progressing well, especially since the first Chianina xWatussi individual was born recently

Saturday, 6 April 2019

Horn shape evolution in Oostvaardersplassen

I already covered my suspicion that Heck cattle are morphologically changing in the Oostvaardersplassen reserve due to natural selection in a number of posts, see here, here or here. Each of these posts provide photos of individuals endorsing my suspicion. 

And so does this post. A number of individuals in the Oostvaardersplassen reserve show horns that are definitely curving inwards and facing more or less forwards in an aurochs-like manner. Here are photos that I recently discovered via google search: 

- Photo 1 
- Photo 2
- Photo 3 (cow in the front, left)

I am convinced that these three photos all show the same individual and I think it is quite likely that it is the same as on older photos like this one, just fully mature. On photo 2 linked above you also see a cow in the background that also has remotely aurochs-like horns. On photos available in the web, there is also another individual on older photos that shows the same colour morph and horn shape as the cow in the background on photo 2 but more mature, so there are at least 3 individuals born in Oostvaardersplassen that show an aurochs-like horn shape. 

What is striking is that I haven't ever seen any Heck cattle in real or on photos (contemporary or historic) outside of Oostvaardersplassen that show this horn shape, indicating that this phenotype might be unique to the population within the Heck cattle gene pool. While body shape and to a certain degree maybe also proportions can be influenced by phenotypic plasticity, I see now plausible way how phenotypic plasticity may influence horn shape that visibly. Therefore, I think that we see a true shift of allele frequency due to selective pressure, and thus evolution, in the Oostvaardersplassen that is at the same time also a regression towards the wildtype. This is an assumption that endorses a concept of dedomestication as outlined in the dedomestication series

A puzzling question is why we see this tendency only in cows, and not in bulls so far. 

Aurochs model update

About one month passed since my latest aurochs model update, so it is time for another one (please do not use the photos without permission). 

This is what the model looked like about one week ago. The height at the withers is still 33cm. I corrected the nose, added ears, eyelids, tail and penis and scrotum (without the tuft the model looks a bit like an ox to me, by the way). I also made the ribcage broader by about 1cm (not really detectable on the photo). 

As you see on the photos, the back of my model was slightly sloping at this stage - we never see this in wild bovines, only in domestic cattle, which is why I consider that a domestic trait and corrected it afterwards. In the meantime I also sculpted the forelocks, mane and other coat details a European aurochs bull probably had, and now that the body is more or less finished, I start doing the horns. Photos are about to come. 

I have to say it is very exciting and also teaching to do this model. I learned a lot about the three-dimensional anatomy of bovines and I am very enthusiastic about how the model works out. I am incredibly looking forward to doing the horns and painting.