[9] Camelids originated in North America during the Eocene, with the ancestor of modern camels, Paracamelus, migrating across the Bering land bridge into Asia during the late Miocene, around 6 million years ago.

[15] The male dromedary camel has an organ called a dulla in his throat, a large, inflatable sac that he extrudes from his mouth when in rut to assert dominance and attract females.

[20][21] Camels have a series of physiological adaptations that allow them to withstand long periods of time without any external source of water.

[23] The dromedary camel can drink as seldom as once every 10 days even under very hot conditions, and can lose up to 30% of its body mass due to dehydration.

This facilitates the flow of red blood cells during dehydration[25] and makes them better at withstanding high osmotic variation without rupturing when drinking large amounts of water.

[31] Camels eating green herbage can ingest sufficient moisture in milder conditions to maintain their bodies' hydrated state without the need for drinking.

These two major anatomical characteristics enable camels to conserve water and limit the volume of urine in extreme desert conditions.

[43] These "heavy-chain-only" antibodies, discovered in 1993, are thought to have developed 50 million years ago, after camelids split from ruminants and pigs.

[57] Scientists collected semen from a camel via an artificial vagina and inseminated a llama after stimulating ovulation with gonadotrophin injections.

[66] The ancestor of modern camels, Paracamelus, migrated into Eurasia from North America via Beringia during the late Miocene, between 7.5 and 6.5 million years ago.

[72] The last camel native to North America was Camelops hesternus, which vanished along with horses, short-faced bears, mammoths and mastodons, ground sloths, sabertooth cats, and many other megafauna as part of the Quaternary extinction event, coinciding with the migration of humans from Asia at the end of the Pleistocene, around 13–11,000 years ago.

[84] In 2009–2013, excavations in the Timna Valley by Lidar Sapir-Hen and Erez Ben-Yosef discovered what may be the earliest domestic camel bones yet found in Israel or even outside the Arabian Peninsula, dating to around 930 BC.

This garnered considerable media coverage, as it is strong evidence that the stories of Abraham, Jacob, Esau, and Joseph were written after this time.

[88] The official report by Sapir-Hen and Ben-Joseph says: The introduction of the dromedary camel (Camelus dromedarius) as a pack animal to the southern Levant ... substantially facilitated trade across the vast deserts of Arabia, promoting both economic and social change (e.g., Kohler 1984; Borowski 1998: 112–116; Jasmin 2005).

Most scholars today agree that the dromedary was exploited as a pack animal sometime in the early Iron Age (not before the 12th century [BC])and concludes: Current data from copper smelting sites of the Aravah Valley enable us to pinpoint the introduction of domestic camels to the southern Levant more precisely based on stratigraphic contexts associated with an extensive suite of radiocarbon dates.

The coincidence of this event with a major reorganization of the copper industry of the region—attributed to the results of the campaign of Pharaoh Shoshenq I—raises the possibility that the two were connected, and that camels were introduced as part of the efforts to improve efficiency by facilitating trade.

[97] France created a méhariste camel corps in 1912 as part of the Armée d'Afrique in the Sahara[103] in order to exercise greater control over the camel-riding Tuareg and Arab insurgents, as previous efforts to defeat them on foot had failed.

[111] At the same period the Soviet units operating around Astrakhan in 1942 adopted local camels as draft animals due to shortage of trucks and horses, and kept them even after moving out of the area.

[125] Developing less wasteful uses of the milk, the FAO commissioned Professor J.P. Ramet of the École Nationale Supérieure d'Agronomie et des Industries Alimentaires, who was able to produce curdling by the addition of calcium phosphate and vegetable rennet in the 1990s.

[133] On the other hand, camel milk and meat are rich in protein, vitamins, glycogen, and other nutrients making them essential in the diet of many people.

It does well even in arid areas due to its unusual physiological behaviors and characteristics, which include tolerance to extreme temperatures, radiation from the sun, water paucity, rugged landscape and low vegetation.

[136][137] The Abu Dhabi Officers' Club serves a camel burger mixed with beef or lamb fat in order to improve the texture and taste.

[18][132][142] A 2005 report issued jointly by the Saudi Ministry of Health and the United States Centers for Disease Control and Prevention details four cases of human bubonic plague resulting from the ingestion of raw camel liver.

The feral nature of the animals means they produce a different type of meat to farmed camels in other parts of the world,[145] and it is sought after because it is disease-free, and a unique genetic group.

"[151] The Palestinian Muslim Makhamara clan in Yatta, who claim descent from Jews, reportedly avoid eating camel meat, a practice cited as evidence of their Jewish origins.

[155] Dromedaries alive today are domesticated animals (mostly living in the Horn of Africa, the Sahel, Maghreb, Middle East and South Asia).

The Horn region alone has the largest concentration of camels in the world,[22] where the dromedaries constitute an important part of local nomadic life.

[124][156][157][158] Over one million dromedary camels are estimated to be feral in Australia, descended from those introduced as a method of transport in the 19th and early 20th centuries.

[142][155][161] Representatives of the Australian government have culled more than 100,000 of the animals in part because the camels use too much of the limited resources needed by sheep farmers.

The wild camels are critically endangered and number approximately 950, inhabiting the Gobi and Taklamakan Deserts in China and Mongolia.