Characteristics of the Aurochs

The colour traits of the Aurochs are familiar to many people, as is the fact that the aurochs had large horns and was considerable larger than most domestic cattle. But there is much more that defines its appearance, as there are some gross differences in morphology between the aurochs and usual domestic cattle. The current Wikipedia article on the aurochs provides a lot of information on these differences. I made a little table showing the most important characteristics of an aurochs at one glance:

We know about these traits because there are a) numerous well-preserved specimen of the aurochs, b) historic references describing and Palaeolithic paintings depicting the aurochs, c) close living relatives (Banteng, Gaur) and less-derived cattle that provide helpful analogues.

Reconstructed range of the subspecies of the wild Aurochs (Image source: Wikipedia)

Was the aurochs very variable in appearance? Most material, be it skeletal or historic, is from the western subspecies, Bos primigenius primigenius. It certainly was the most important subclade as it had the largest range and survived to most recent times. There also was an Indian subspecies, Bos primigenius namadicus, for which only fragmentary skeletal material and no historic references are known. The North African aurochs, Bos primigenius africanus, is less enigmatic, but still not as well-documented as the European Aurochs since it died out one or two millennia earlier.

Heck cattle breeders (but also some other people involved in breeding-back) claim the aurochs was very variable from region to region, what justifies the variability of breeding-back results and the presence of phenotypic features not supported by the data. But it seems that this wasn’t the case. Surely, most skeletal material of the aurochs is from Central and Northern Europe, but it seems that the North African and also the Near Eastern aurochs was nearly indistinguishable from the aurochs on the osteologic level.  When having a look at the many beautifully preserved skulls of this wild bovine, it becomes clear that there was considerable variation in relative size and thickness, but they always displayed the same basic curvature, with some differences in the exact expression of this curvature. Some specimen had more upright horns than others, but the angle between horns and snout nearly always varied between 70° and 50°. How about the colour of the aurochs? It’s true that historic references describing the colour of the aurochs all come from the northern part of Central and Eastern Europe, but the famous cave paintings of Lascaux and Chauvet (from Southern Europe of the late Pleistocene) show the same pelage characteristics. And this basic colour can be found in some subspecies of the Banteng and Gaur as well (albeit with reduced markings in the coat).  So there is little reason to believe the colour of the aurochs was very variable. However, there are engravings found in Libya showing aurochs with a light saddle on the back. Cis van Vuure identifies reddish cattle with white saddles and lyre-shaped horns illustrated on Egyptian tomb paintings as domestic cattle, but the engravings from Libya show aurochs-like animals (with typical aurochs horns) that are depicted being hunted, so this could be considered evidence for North African aurochs having had a light saddle on the back. Furthermore, Gloger’s rule states that animals (birds in particular, by the way) are less melanised in arid than in humid habitats. This could enhance the assumption that North African aurochs had less eumelanin in their pelage, and therefore a light saddle.

To put it in a nutshell, it is likely that the appearance of the aurochs probably was not all too variable over its range, at least concerning its bodily proportions, skull and horn shape (size may be another story). There is no evidence for the existence of aurochs populations not having long legs and skulls, a strongly developed shoulder region, or displaying a considerably different horn shape. However, there maybe were minor colour differences between the different subspecies. Therefore, the aurochs likely was not any more variable than other large herbivores with a large and continuous range. Breeding-back should focus on this stable appearance as long as there is no solid evidence for populations showing divergent physical traits.

Literature

• van Vuure, Cis: Retracing the Aurochs - History, Morphology and Ecology of an extinct wild Ox. 2005.
• van Vuure, Cis: History, Morphology and Ecology of the Aurochs (Bos primigenius). 2002.
• Frisch, Walter: Der Auerochs – das europäische Rind. 2010.