The lateral horn orientation

When it comes to the horns of aurochs and cattle, I usually differentiate them into three factors to compare them: the actual shape of the horn, the dimensions (length and diameter) and the orientation relative to the skull. All those three factors can vary among cattle. When thinking of the horn orientation, I only considered the orientation relative to the snout. In the European aurochs, this angle usually varied from 50-80°, with some individuals being exceptions. I did not notice that the horn orientation also has another variable that has quite an impact on how we perceive the horn “shape” (the shape actually does not change, but it appears as if it did when the orientation is changed), what I call the lateral horn orientation. This factor is the orientation of the horn in the plane that is 90° to the sagittal plane of the animal, in other words, the horn orientation relative to the side of the animal. I did not realize the lateral horn orientation is a factor before I did a photo manipulation morphing the Taurus cow Lerida into an aurochs cow, where I had to slightly elevate the lateral horn orientation of the cow in order to make the horns appear more aurochs-like. 

Another good example that the LHO is relevant are the horns of many Sayaguesa. Looking at the head of one of the Sayaguesa cows grazing in the Lippeaue, at first glance one would say the horn tips do not face inwards enough because they point right towards the sky and that the primigenius spiral is not present: 

But elevating the LHO, so that the proximal half of the horns do not point downwards but slightly upwards, an aurochs-like horn curvature with the primigenius spiral appears (the shape of the horn was not changed, showing that it already had an aurochs-like shape): 

So I did a sketch playing around with the LHO: 

 

I sketched an aurochs horn that I copied and mirrored, and positioned with a different LHO four times. The uppermost sketch shows a LHO rather elevated, as can be seen in the skull fragment of Asti and Gramsbergen (both likely belonged to cows). The second one counting from the top shows the LHO slightly elevated, as exhibited by the vast majority of aurochs skulls (f.e. the Sassenberg bull, the Nagybajom bull etc.). The third one shows the LHO in a horizontal position, seen in for example the Arezzo skull, some Lidia, some Maronesa, some Sayaguesa bulls. The fourth shows the LHO oriented downwards, a condition that did not appear in the wildtype (at least no skull with such a horn orientation has been found so far), but is found in many Lidia and many Sayaguesa. 

 

Looking at the horns of the, in my opinion, most aurochs-like “breeding-back” population, the Taurus cattle from the Lippeaue, it turns out that their LHO could be more elevated, as seen in the Lerida example. Watussi might improve this a bit. The Hungarian Taurus population from Hortobagyi, which has influence from Watussi, indeed has a more elevated LHO on average, but there is also Steinberg/Wörth Heck cattle and Hungarian Grey cattle in the mix. Wild yaks would help as well, perhaps better than Watussi as their horns are identical to those of the European aurochs.