Donkeys (Equus asinus)

History of the Domestication of Donkeys

The modern domestic donkey (Equus asinus) was bred from the wild African ass (E. africanus) in northeastern Africa during the predynastic period of Egypt, about 6,000 years ago. Two wild ass subspecies are thought to have had a role in the development of the modern donkey: the Nubian ass (Equus africanus africanus) and the Somali ass (E. africanus somaliensis), although recent mtDNA analysis suggests that only the Nubian ass contributed genetically to the domestic donkey. Both of these asses are still alive today, but both are listed as critically endangered on the IUCN Red List.

The donkey's relationship with the Egyptian civilization is well-documented. For example, murals in the tomb of the New Kingdom pharaoh Tutankhamun illustrate nobles participating in a wild ass hunt. However, the real importance of the donkey relates to its use as a pack animal. Donkeys are desert-adapted and can carry heavy loads through arid lands allowing pastoralists to move their households with their herds. In addition, donkeys proved ideal for the transport of food and trade goods throughout Africa and Asia.

Domestic Donkeys and Archaeology

Archaeological evidence used to identify domesticated donkeys includes changes in body morphology. Domestic donkeys are smaller than wild ones, and in particular they have smaller and less robust metacarpals (foot bones). In addition, donkey burials have been noted at some sites; such burials likely reflect the value of trusted domestic animals. Pathological evidence of damage to spinal columns resulting from donkey's use (maybe overuse) as pack animals is also seen on domestic donkeys, a situation not thought likely on their wild progenitors.

The earliest domesticated donkey bones identified archaeologically date to 4600-4000 BC, at the site of El-Omari, a predynastic Maadi site in Upper Egypt near Cairo. Articulated donkey skeletons have been found buried in special tombs within the cemeteries of several predynastic sites, including Abydos (ca. 3000 BC) and Tarkhan (ca. 2850 BC). Donkey bones also have been discovered at sites in Syria, Iran and Iraq between 2800-2500 BC. The site of Uan Muhuggiag in Libya has domestic donkey bones dated to ~3000 years ago.

Domestic Donkeys at Abydos

A 2008 study (Rossel et al.) examined 10 donkey skeletons buried at the predynastic site of Abydos (about ca 3000 BC). The burials were in three purposefully constructed brick tombs adjacent to the cult enclosure of an early (so far unnamed) Egyptian king. The donkey tombs lacked grave goods and in fact only contained articulated donkey skeletons.

An analysis of the skeletons, and comparison with modern and ancient animals revealed that the donkeys had been used as beasts of burden, evidenced by signs of strain on their vertebral bones. In addition, the body morphology of the donkeys was midway between wild asses and modern donkeys, leading researchers to argue that the domestication process was not complete by the end of the predynastic period, but instead continued as a slow process over periods of several centuries.

Donkey DNA

DNA sequencing of ancient, historic and modern samples of donkeys throughout northeastern Africa was reported (Kimura et al) in 2010, including data from the site of Uan Muhuggiag in Libya. This study suggests that domestic donkeys are derived solely from the Nubian wild ass.

Results of the testing demonstrate that Nubian and Somali wild asses have distinct mitochondrial DNA sequences. Historic domestic donkeys appear to be genetically identical to Nubian wild asses, suggesting that modern Nubian wild asses are actually survivors of previously domesticated animals.

Further, it seems likely that wild asses were domesticated several times, by cattle herders perhaps beginning as long ago as 8900-8400 calibrated years ago cal BP. Interbreeding between wild and domestic asses (called introgression) is likely to have continued throughout the domestication process. However, Bronze Age Egyptian asses (ca 3000 BC at Abydos) were morphologically wild, suggesting either that the process was a long slow one, or that wild asses had characteristics that were favored over domestic ones for some activities.

Sources

This article is part of the About.com Guide to the History of Animal Domestication.

Beja-Pereira, Albano, et al. 2004 African origins of the domestic donkey. Science 304:1781.

Kimura B, Marshall FB, Chen S, Rosenbom S, Moehlman PD, Tuross N, Sabin RC, Peters J, Barich B, Yohannes H et al. 2010. Ancient DNA from Nubian and Somali wild ass provides insights into donkey ancestry and domestication. Proceedings of the Royal Society B: Biological Sciences:(online pre-publish).

Rossel, Stine, et al. 2008 Domestication of the donkey: Timing, processes, and indicators.Proceedings of the National Academy of Sciences 105(10):3715-3720.

This glossary entry is part of the Dictionary of Archaeology. Any mistakes are the responsibility of Kris Hirst.

Source: about.com