Did the African aurochs die out because of aridification?

It is well-known that the aurochs was wiped out by humans. It was mainly a combination of hunting, competition for habitat and competition with livestock that caused the extinction of this wild bovine. This goes for the wildtype as a whole, but it does not rule out that single populations or subspecies died out because of “natural” (i.e. non-anthropogenic) causes. This was, for example, the case with the Sicilian dwarf aurochs, Bos primigenius siciliae, which likely was outcompeted by the large mainland form when a land bridge between the mainland and the island formed at the last glacial maximum. For the African aurochs, Bos primigenius mauretanicus, there are not many works that cover possible extinction causes for this form specifically. However, there is at least one, which is Faith 2013 [1]. This work attributes the extinction of the aurochs in Africa to an aridification of its environment in North Africa around 6kya. How plausible is this? 

This idea sounds plausible for three reasons: 1) the Holocene was anything but climatically stable, and during the Atlantic period there was the so-called Holocene Climatic Optimum, during which it was warmer than today and even the Fertile crescent aridificated [2], 2) the aurochs was an animal that preferred wetter habitats and did not inhabit steppe, semi-deserts or deserts, thus an aridification could have been harmful, 3) the Mediterranean see would have hindered the aurochs from migrating northwards to less arid and more humid regions. 

There is, however, a significant problem with the idea that aridification caused the aurochs to disappear in Africa: the African aurochs did not disappear at 6kya. Bone findings suggest that the African aurochs survived at least until 1000 BC [3,4]. Furthermore, the hunting of aurochs is documented in ancient Egyptian art and hieroglyphs [3]. Less unambiguous is the mentioning of bovines with horns so large and forwards-facing that the animals had to graze backwards in Egypt by Herodotos from the 5^th century BC [4]. 

I would not be surprised if the Nile served as a refuge of the aurochs during the aridification in the Mid-Holocene, as the aurochs is dependent on wet and plane areas. After the warm and dry period during the Holocene Climatic Optimum was over, the range of the aurochs would have expanded again. But now the bovine had a competitor, humans, who competed for exactly the same habitat that the aurochs preferred. Additionally, humans hunted the bovine. So it seems that in North Africa exactly the same happened as in Europe and elsewhere, the aurochs simply had no chance in competing with humans for the same habitat additionally to being hunted. The aridification as a result of the changing climate during the Mid-Holocene cannot be blamed for the extinction of the African aurochs. 

 

References

 

[1] Faith, J.T.: Late Pleistocene and Holocene mammal extinctions on continental Africa. 2013.

[2] Vinos, J.: Climate of the past, present and future: A scientific debate, 2^nd ed. 2022.

[3] Beierkuhnlein, C.: Bos primigenius in Ancient Egyptian art – historical evidence for the continuity of occurrence and ecology of an extinct key species. 2015. 

[4] van Vuure, C.: Retracing the aurochs – history, morphology and ecology of an extinct wild ox. 2005.