Аңдатпа
The expansion of large camelids around the world has continued since their domestication. Trade routes and warfare were historically the main ways for the species expansion in Middle-East and North Africa. Camel farming is not limited to arid countries nowadays. There is a growing camel dairy industry in Western countries. Large camelids have long been called the “ships of the desert” for their importance in the desert regions of Africa and Eurasia. Although their reputation as an animal of the nomads and for caravans of merchants recalls their mobility far exceeding that of other domestic herbivores, the use of this species for transportation and in animal agriculture remains confined to the deserts of northern Africa and Asia. However, the geographical distribution of large camelids has grown in the last 30 years. As they gain popularity, the species has been confronted with new environmental contexts. So much so that one may wonder if they are not conquering the world. Here, we take a closer look at the journey of the camel from its early ages of domestication to its role in a world facing climate change. The large camelid family originated in North America about 40 million years ago. From this original nucleus, two migrations, one to South America through the Isthmus of Panama, the other to the Asian continent via the Bering Strait, gave rise to the two current large branches of the camelid family: the small Andean camelids (Lamini tribe) and the large camelids (Camelini tribe). The divergence between these two groups occurred 11 million years ago in North America, and the ancestor of the small camelids, the Palaelama, would have arrived in the Andean mountains between 1.8 million years and 11,000 years before our era (BP) (Wheeler, 1994). For its part, the ancestor of the great camelids (Camelops?) would have migrated to Asia between 8 million years and 15,000 years BP (Burger, 2016). The large camelids in turn divided into the dromedary (one-humped camel) and the Bactrian (two-humped camel), 4–5 million years ago, the former migrating to the hot lands of the Arabian Peninsula, the latter to the cold lands of central Asia (Burger et al., 2019). A final divergence occurred less than a million years ago between the Bactrian camel and the wild camel of Tartary (Hare, 1999). The current family of large camelids includes three genera and seven species. The genus Camelus includes two domestic species which are the dromedary (Camelus dromedarius) also called the Arabian camel or single-humped camel, the Bactrian (Camelus bactrianus) or double-humped camel, sometimes called the Asian or Mongolian camel. The wild camel (Camelus ferus), long regarded as Bactrian camel that remained wild (ancestor of present Bactrian camel) has recently been recognized as a different species through genetic studies showing a clear divergence in the full genotype. C. ferus is therefore a “cousin” and not a direct ancestor of the Bactrian camel. Domestication occurred for Bactrian camel between 5,000 and 6,000 years ago, likely in an area more western than previously thought, toward Uzbekistan and present West Kazakhstan, rather than toward Mongolia. The name “Bactrian” comes from a region (former kingdom conquered by Alexander the Great) located between Afghanistan, Iran, and Kazakhstan (Burger et al., 2019). The domestication of the dromedary would be more recent (3,000–4,000 years) and likely occurred in the south-east of the Arabian Peninsula (current Sultanate of Oman, United Arab Emirates, and southern Saudi Arabia) (Fitak et al., 2020). According to current data, large camelids are therefore among the last large species domesticated by humans (Figure 1). Approximate dates of domestication of animals (retrieved from https://fr.mahnazmezon.com/articles/science/animal-domestication-table-of-dates-and-places.html). Thus, the population of Bactrian and dromedary camels in the process of domestication was limited to a relatively small geographical area, Central Asia for the former, South of the Arabian Peninsula for the latter. This implies a total separation of the two species that were domesticated in the Asian space. Indeed, the camelid family expanded long after domestication with the creation of crossbreeds and hybrids. Crossbreeding between dromedaries and Bactrian camels was practiced all along the trade routes of the Asian continent (“Silk Roads”), and the new animal combined the strength of the Bactrian and the endurance of the dromedary, necessary qualities in caravan travel. Crossbreeding is popular nowadays to obtain females that produce more milk than their parents and are higher in fat by heterosis effect (Faye and Konuspayeva, 2012). Such practice is common in Kazakhstan for dairy production and in Turkey for wrestling (Dioli, 2020), a very popular cultural event in Anatolia. Crossbreeding is still common today. Different breeding schemes occur, depending on whether the male is a dromedary or Bactrian camel at different generations, leading to a range of crossbreeds distinguished by a more or less subdivided large hump on the back and fur distribution (Figure 2). Crossbreed dromedary*Bactrian for wrestling in Turkey (Photo: Bernard Faye). In addition, true intertribal hybridization has occurred with the crossing between a dromedary and lama at an experimental farm. It led to a sterile animal named the cama (Skidmore et al., 2002). However, the expansion of camelid family by crossbreeding requires previously an expansion of the geographical distribution of each species. This expansion was linked to desertification, war, and trade. The two species of domestic camel were known and described by the ancient Greek and Roman thinkers of the time: Aeschylus, Herodotus, Aristotle, or Pliny (Agut-Labordère and Redon, 2020). As early as the first century before Christian Era (BC), the Romans readily distinguished the camel, a pack animal devoted to the transport of goods, from the dromedary, a saddle animal used by the Roman meharists (i.e., using camel as riding animal). Formally, the word “dromedary” designated only racing or riding camels, and the word “camel” was for pack camels. The words did not distinguish between the two species with one hump (now called the dromedary) and two humps (Bactrian), both being camels. However, the migration of the dromedary to the African continent started earlier than the Roman empire. The introduction of the dromedary camel in the Egyptian desert is attested during the first millennium BC but was limited to commercial incursions for carrying goods from the Arabian Peninsula. Its presence increased from the 5th century BC accompanied a significant increase in activity on desert roads, improving the capacities of the caravans formerly reliant on donkeys and mules. Through their presence, the dromedaries boosted the relationships between the Eastern Desert of Egypt to the Nile Valley and beyond, cementing ties between the Asian and African world (Agut-Labordère and Redon, 2020). According to some historical sources, the introduction of the dromedary camel in Egypt through the Sinai Peninsula is probably linked to the Assyrian invaders from the beginning of the 7th century BC and to Persian invaders in the region at the end of the 6th century BC. But in all cases, the dromedary camels were in the hands of the Arab tribes (Barnard, 2012). At the same time, the Sahara became arid (the aridity started around 3900 BC), leading to a favorable environment for the camel (Jung et al., 2004). The presence of the dromedary camel in the western Egyptian desert occurred since the end of the 5th century BC. Yet, access to camels in central part of the Sahara appeared slightly before the Roman Empire, as documented by petroglyphs in the Libyan desert. Thus, from the Arabian Peninsula, Near-East and Egypt, the dromedary camel started its expansion into the Sahara alongside desertification. Regarding the Bactrian camel, its presence was documented since the 4th millennium BC outside its cradle in Central Asia, reaching the Iranian plateau and the city of Sumer at the end of the IIIrd millennium BC where probably the first crossbreeding with the dromedary occurred (Fitak et al., 2020). The Bactrian camel was depicted in Assyria (actual North Iraq) on an obelisk dated 825 BC, attesting to the history of the double-humped camel in the Near-East. The presence of the Bactrian camel was also documented in Mongolian petroglyphs dating from 2,000 to 3,000 BC and in Western China over 1,000 BC (Yam and Khomeiri, 2015). Finally, at the beginning of the Christian era, dromedary and Bactrian camels occupied already most of the arid lands of the Old World in Africa and Asia, from Mauritania to Western China, with an incursion in the European part of the Roman Empire, up to Germany (Pigière and Henrotay, 2012). If the geographical expansion of the camel accompanied desertification, the mobility of the camel herds was linked mainly to war and trade. The use of camels as riding and pack animals is probably as old as their domestication, as evidenced by petroglyphs in Saudi Arabia or Mongolia (Figure 3). Petroglyphs showing people hunting antelope on Bactrian camel back (Alashan desert, Inner Mongolia, China) (Photo: Bernard Faye). These two functions (packing and riding) are highly useful for a mobile army. Sumerian frescoes, dating from 2000 BC, show raids from the current north of Saudi Arabia toward the Tigre and Euphrates valleys, conducted by Arab tribes mounted on camels. The camel in war is not only used for carrying the fighters but also for the transportation of goods intended for the army: forages for the horses, weapons, and all types of military supplies. In antiquity, camels were also regularly represented on frescoes, in cases of victory, both as booty and as a means of taking away the furniture loot. Dromedary camels participated in many military campaigns in Egypt, notably in the 6–5th centuries BC, supported by the Persians and the Assyrians, with the support of the Arab tribes (Cousin, 2020). Later, during the Arab conquest, the dromedary camel accompanied the Arab troops through the north of Africa to Spain (Insoll, 1996). The use of camels for war led even Napoléon Bonaparte, in collaboration with Desaix, to create a dromedary camel regiment during his Egypt campaign in 1799 (Cvikel and Goren, 2008). Such military activities continue today through the “Meharist companies” and other “camel corps” maintained in desert countries, even if the advent of 4 × 4 vehicles tends to limit the interest of such units in modern conflicts (Wilson, 2016). These military campaigns allowed for the expansion of camels through arid lands of the Old World, away from where animals were domesticated; however, these main routes for invasion followed pre-established trade routes. The use of large camelids as pack animals along trade routes is probably as old as domestication, particularly in the Arabian Peninsula, the cradle of the domestic dromedary. The legend of the Queen of Sheba, for example, likely symbolizes the birth of trade, with caravans from the Kingdom of Sheba (present-day Yemen) taking gold and spices to the land of Solomon (present-day Israel) and returning south, loaded with olive oil and grain. There is sufficient archeological evidence confirming the presence of trade routes in the Peninsula from the 12th century BC (Finkelstein, 1988) called the “incense roads,” unifying the south of Arabia to Mediterranean Sea and Mesopotamia thanks to caravans of dromedaries. Bactrian camels and probably hybrids (crossbred dromedary*Bactrian) were widely involved in the “Silk Road” unifying the Far-East (China) and Europe (Frankopan, 2015). After the migration of dromedary in the north of Africa accompanying the Islamic conversion of West Africa (7–8th centuries after Christian Era) many trans-Saharan trade routes contributed to the link between the north and south margins of Sahara, justifying the camel’s nickname of “ship of desert,” given by the Arab people. Trade routes occurred between the western desert from modern Morocco, contributing to the development of oases like Sigilmassa to the Niger Bend and to the development of Timbuktu (Lightfoot and Miller, 1996). Other routes from Tunisia to the Lake Chad area, from the east of the Fezzan to Lake Chad, or from the Nile Valley in present Sudan to Egypt fueled the expansion of the dromedary all over arid lands of northern Africa. Thus, dromedary and Bactrian camels contributed to territorial connectivity. They moved huge quantities of wealth over thousands of kilometers from the Chinese Empire to the Roman Empire. As they crossed, the camels opened the region up to oases, water points, and nomads. Despite the current use of trucks, camel caravans still operate across short distances. They are also used today to transport nonperishable products, such as salt or dried cereals, in very remote places, or in some cases, manufactured products of contraband. Trade routes have opened new territories for the animal, contributing notably to cross-continental dispersal of camel genes (Almathen et al., 2016). Historically, camels have moved along trade routes and been raised in dedicated “caravanserais” operations, rather than living at established farms (Faye et al., 2017). The camel farming systems established in the between-oasis space were based on the mobility of the herds (nomadism or transhumance). However, this tradition is changing today under pressure from climatic changes and the globalization of the world economy. Indeed, since the droughts that struck Sahelian countries beginning in the 1960s, we have witnessed an expansion of the dromedary camel distribution area, including the southern part of countries as Mali, Niger, and Chad, but also neighboring countries as Senegal, Burkina Faso, Nigeria, Cameroon, and even Tanzania and Uganda (Faye et al., 2012; Wilson, 2017). In mountainous countries, such as Ethiopia, camels have expanded into higher altitudes in just the last 20 years, and the altitude limit of camel farming expanded from 1,500 m in the 1980s to 2,000 m today (Tefera and Abebe, 2012; Wilson, 2020). Even in equatorial countries, such as Uganda, camels are now used to secure their farming systems facing recurrent droughts (Asiimwe et al., 2020) contributing to an increase in the local camel population to more than 40,000 heads. Overall, the boundary for camel farming expansion in Sahelian Africa has migrated southwards over more than 500 km in 30 years (Faye, 2020). This expansion appears not only linked to the movement of camel herds usually present in northern part of the Sahelian countries and reared by nomadic people, but also to the “adoption” of the camel by former cattle-breeders as the Peul in West Africa and Maasai in East Africa, that is, by “ethnic transfer” (Faye et al., 2012). The integration of camels in those new territories can be illustrated by a five-fold increase in camels in Sahelian countries since 1961 (Figure 4). Changes in Tropical Livestock Units (TLU) index per species in West, Middle, and Eastern Africa 1961–2019 (calculated from FAOSTAT, 2021). Except in India, where the decline of the camel population has continued since the 1970s (Faye, 2020), camel herds around the world have grown at a regular pace for the last 20 years. This includes the Bactrian camel (Faye, 2020). Since 1961, the world camel population has multiplied by 2.9, has only increased for Even in countries a decline of their camel in the century China, and Central Asian the has been a interest in camel breeding in recent with FAOSTAT, more than million an the camel population only of the Tropical Livestock Units to the mobility of camels through and to the many the for has only been slightly different camel are distinguished by their their their and their mainly based on have some but these are not by studies et al., 2015). A pressure with geographical over a large region has led to a of linked to different rather than The domestic camel population has a relatively genetic (Burger et al., 2019). Although was that two main from the Arabia Peninsula led to all dromedary camels in the world (Almathen et al., and trans-Saharan routes have leading to a population at the (Burger et al., 2019). In Asia, camel along commercial routes contributed also to between domestic Bactrian camels and dromedaries living in Central Asia, notably in Iran, Kazakhstan, and et al., 2020). However, thanks to current on based on their and be to groups and to the of true camel with functions and 2019). However, camel also be by the new of the species. There is a history of camels to places, such as the and Africa (Faye, 2020). Camel was to the as a animals in the century and and to as animals in the century and Although most of this population became are new to for and milk et al., 2020). In the desert of southern Africa, the dromedary camel was also in the century in by after for in some or commercial farms in and neighboring countries et al., 2019). In Asia, the camel countries in with the of a camel dairy in and Wilson, 2019). However, the most recent have been in the western countries where the environment not a desert the presence of camel in Europe for or commercial activities was already established during the Roman Empire, as and in the in the part of the continent and but camels were limited to and It was only in the last 30 years that camel including for dairy were established in different European countries, such as the and (Figure in The was the first camel dairy in Europe and contributing to the of agriculture camel dairy in (Photo: Bernard Faye). In the United the first camels were in by a but the first occurred in the of the century for military use in the desert of the around 3,000 camels on farms as and for dairy A of camel dairy camel milk and milk products on their for and contributing to the rise of the camel milk all over the world et al., 2021). recent conflicts in the world have occurred in camel countries Western Sahara, Mali, Niger, Nigeria, Ethiopia, and among These conflicts not camel but have on the movement and migration of with their for from to This migration to the of the camel dairy industry in and other large et al., 2012). after the between and Saudi Arabia in around camels were to back to after the Saudi their presence in the between the two countries in some of Western and Africa Niger Nigeria, to significant changes in the camel as for from Chad to the merchants to camels to Egypt, by Sudan for the changes in the routes between Niger and Chad as occupied by the Despite being by camels have a role in of the most of by the camel was the former of camels to the many of in the from South Africa to (Wilson, also the camel given by the of to the after the military a in even if the animal was in The of the large camelids is still A camel can be regarded as an animal of the in of between and (Faye and the link between and camel is with a and as they in But in their original are dromedaries and still “ships of the the deserts of Arabia and the East are by and the 4 × 4 of have caravans to transport goods from one city to The in the of the region have led to the decline of the camel since this in 1961 and the of in the total Saudi population increased from to Yet, the with the and its the of has continued to is the camel has other ways of development and Despite this the camel remains an on the of most desert countries, the camel’s are present in or at the of animal would In the camel is as a central of as is the if not of at of the of an animal the of the desert to be in with his environment et al., the dromedary is a central of the Although now many in the or other countries in among the camels that they still under the of a of (Figure (Faye, 2016). A camel for the in Saudi Arabia (Photo: Bernard Faye). Even depending on the of the of the East in camel The dromedary is part of his sometimes of his or that of his parents or family the of is a to in the desert. In Saudi these more or less into the a of the camel farms and Thus, the expansion of the large camelids that we are is not only a of but also of and less “ship of the desert,” the camel functions more than before and more its with the of the desert, even if they in from the Arabian Peninsula and Central Asia, large camelids have conquered all the deserts of the Old World and have now more in of and water The that we are today for the animal and its products may its of the world. However, such an expansion of the species also for and the of this species in these new and contexts. Bernard in and in Africa for 8 years for and development activities before the of as of the for in for as of as interest in camels in in through his in and his of camel Western and of Africa, India, Central Asia, the for and on At present of and of the of camelids From to in Saudi Arabia as an in a camel At at and camel of more than in and and in and and