Tuesday, November 5, 2019

Dromedary Camel (Camelus dromedarius)

Dromedary Camel (Camelus dromedarius) The dromedary (Camelus dromedarius or one-humped camel) is one of a half-dozen of camel species left on the planet, including llamas, alpacas, vicunas, and guanacos in South America, as well as its cousin, the two-humped Bactrian camel. All evolved from a common ancestor some 40-45 million years ago in North America. The dromedary was probably domesticated from wild ancestors roaming in the Arabian peninsula. Scholars believe that the likely site of domestication was in coastal settlements along the southern Arabian peninsula somewhere between 3000 and 2500 BC. Like its cousin the Bactrian camel, the dromedary carries energy in the form of fat in its hump and abdomen and can survive on little or no water or food for quite a long period. As such, the dromedary was (and is) prized for its ability to endure treks across the arid deserts of the Middle East and Africa. Camel transport greatly enhanced overland trade throughout Arabia particularly during the Iron Age, extending international contacts throughout the region along caravansaries. Art and Incense Dromedaries are illustrated as being hunted in New Kingdom Egyptian art during the Bronze Age (12th century BC), and by the Late Bronze Age, they were fairly ubiquitous across Arabia. Herds are attested from Iron Age Tell Abraq on the Persian Gulf. The dromedary is associated with the emergence of the incense route, along the western edge of the Arabian peninsula; and the ease of camel travel compared to substantially more dangerous sea navigation increased the use of overland trade routes connecting the Sabaean and later trading establishments between Axum and the Swahili Coast and the rest of the world. Archaeological Sites Archaeological evidence for early dromedary use includes the predynastic site of Qasr Ibrim, in Egypt, where camel dung was identified about 900 BC, and because of its location interpreted as dromedary. Dromedaries did not become ubiquitous in the Nile Valley until about 1,000 years later. The earliest reference to dromedaries in Arabia is the Sihi mandible, a camelid bone direct-dated to ca 7100-7200 BC. Sihi is a Neolithic coastal site in Yemen, and the bone is probably a wild dromedary: it is about 4,000 years earlier than the site itself. See Grigson and others (1989) for additional information about Sihi. Dromedaries have been identified at sites in southeastern Arabia beginning between 5000-6000 years ago. The site of Mleiha in Syria includes a camel graveyard, dated between 300 BC and 200 AD. Finally, dromedaries from the Horn of Africa were found at the Ethiopian site of Laga Oda, dated 1300-1600 AD. The bactrian camel (Camelus bactrianus or two-humped camel) is related to, but, as it turns out, not descended from the wild bactrian camel (C. bactrianus ferus), the only survivor species of the ancient old world camel. Domestication and Habitats Archaeological evidence indicates that the bactrian camel was domesticated in Mongolia and China about 5,000-6,000 years ago, from a now-extinct form of camel. By the 3rd millennium BC, the bactrian camel was spread throughout much of Central Asia. Evidence for the domestication of Bactrian camels has been found as early as 2600 BC at Shahr-i Sokhta (also known as the Burnt City), Iran. Wild bactrians have small, pyramid-shaped humps, thinner legs and a smaller and slender body then their domestic counterparts. A recent genome study of wild and domestic forms (Jirimutu and colleagues) suggested that one characteristic selected for during the domestication process may have been enriched olfactory receptors, the molecules which are responsible for the detection of odors. The original habitat of the bactrian camel extended from the Yellow River in Gansu province of northwest China through Mongolia to central Kazakhstan. Its cousin the wild form lives in northwestern China and southwestern Mongolia particularly in the Outer Altai Gobi Desert. Today, bactrians are mainly herded in the cold deserts of Mongolia and China, where they contribute significantly to the local camel herding economy. Attractive Characteristics Camel characteristics which attracted people to domesticate them are pretty obvious. Camels are biologically adapted to harsh conditions of deserts and semi-deserts, and thus they make it possible for people to travel through or even live in those deserts, despite the aridity and lack of grazing. Daniel Potts (University of Sydney) once called the bactrian the principal means of locomotion for the Silk Road bridge between the old world cultures of the east and west. Bactrians store energy as fat in their humps and abdomens, which enables them to survive for long periods without food or water. In a single day, a camels body temperature can vary safely between an astounding 34-41 degrees Celsius (93-105.8 degrees Fahrenheit). In addition, camels can tolerate a high dietary intake of salt, more than eight times that of cattle and sheep. Recent Research Geneticists (Ji et al.) have recently discovered that feral bactrian, C. bactrianus ferus, is not a direct ancestor, as had been assumed prior to the onset of DNA research, but is instead a separate lineage from a progenitor species which has now disappeared from the planet. There are currently six subspecies of bactrian camel, all descendant from the single bactrian population of the unknown progenitor species. They are divided based on morphological characteristics: C. bactrianus xinjiang, C.b. sunite, C.b. alashan, C.B. red, C.b. brown, and C.b. normal. A behavioral study found that bactrian camels older than 3 months are not allowed to suck milk from their mothers, but have learned to steal milk from other mares in the herd (Brandlova et al.) See page one for information about the  Dromedary Camel.   Sources Boivin, Nicole. Shell Middens, Ships and Seeds: Exploring Coastal Subsistence, Maritime Trade and the Dispersal of Domesticates in and Around the Ancient Arabian Peninsula. Journal of World Prehistory, Dorian Q. Fuller, Volume 22, Issue 2, SpringerLink, June 2009. Brandlov K, BartoÃ… ¡ L, and Haberov T. 2013. Camel calves as opportunistic milk thefts? The first description of allosuckling in domestic bactrian camel (Camelus bactrianus). PLoS One 8(1):e53052. Burger PA, and Palmieri N. 2013. Estimating the Population Mutation Rate from a de novo Assembled Bactrian Camel Genome and Cross-Species Comparison with Dromedary ESTs. Journal of Heredity: March 1, 2013. Cui P, Ji R, Ding F, Qi D, Gao H, Meng H, Yu J, Hu S, and Zhang H. 2007. A complete mitochondrial genome sequence of the wild two-humped camel (Camelus bactrianus ferus): an evolutionary history of camelidae. BMC Genomics 8:241. Gifford-Gonzalez, Diane. Domesticating Animals in Africa: Implications of Genetic and Archaeological Findings. Journal of World Prehistory, Olivier Hanotte, Volume 24, Issue 1, SpringerLink, May 2011. Grigson C, Gowlett JAJ, and Zarins J. 1989. The Camel in Arabia: A Direct Radiocarbon Date, Calibrated to about 7000 BC. Journal of Archaeological Science 16:355-362. Ji R, Cui P, Ding F, Geng J, Gao H, Zhang H, Yu J, Hu S, and Meng H. 2009. Monophyletic origin of domestic bactrian camel (Camelus bactrianus) and its evolutionary relationship with the extant wild camel (Camelus bactrianus ferus). Animal Genetics 40(4):377-382. Jirimutu, Wang Z, Ding G, Chen G, Sun Y, Sun Z, Zhang H, Wang L, Hasi S et al. (The Bactrian Camels Genome Sequencing and Analysis Consortium) 2012. Genome sequences of wild and domestic bactrian camels. Nature Communications 3:1202. Uerpmann HP. 1999. Camel and horse skeletons from protohistoric graves at Mleiha in the Emirate of Sharjah (U.A.E.). Arabian Archaeology and Epigraphy 10(1):102-118. doi:10.1111/j.1600-0471.1999.tb00131.x Vigne J-D. 2011. The origins of animal domestication and husbandry: A major change in the history of humanity and the biosphere. Comptes Rendus Biologies 334(3):171-181.

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