Dromedary Camel, Camelus dromedarius
The dromedary camel (Camelus dromedarius), also known as the Arabian camel, is a completely domesticated species that appears on the IUCN Red List with a conservation status of “Domesticated”. It is thought that when wild, its native range was mainly in the Arabian Peninsula. It can now be found in South Asia, North Africa, and the Middle East. The only dromedary camels that display wild behaviors are the population of feral camels in Australia, which were introduced in 1840. It prefers a habitat in arid regions, like the Sahara desert, and in Africa eighty-four percent of these camels occur in Ethiopia, Sudan, Somalia, Kenya, and Djibouti. Its range overlaps with the Bactrian camel in Afghanistan, although it was noted by Richard Bulliet that these two do not inhabit areas where one is present. It has been introduced into the Canary Islands, where it is still present.
The dromedary camel derives its common name from the Latin word dromedaries, meaning swift, or from the Old French word dromedaire. In the 1560’s, this camel was known as the drumblediary, a variant of its current name. The word camel is a Latin or Greek term derived from the Phoenician or Hebrew term gāmāl, which may mean to carry or bear.
Discovered by Carl Linnaeus in 1758, the dromedary camel was classified into three groups by Arnold Leese, a British veterinarian. These groups included camels from hilly areas, plains, and the areas in between. It was once thought that the dromedary camel and the Bactrian camel were the same species, but this was found to be untrue when Aristotle described them as distinct species based on the number of humps each camel displayed.
Because the dromedary camel and the Bactrian camel are able to breed, it has been thought that the two should be classified as one species separated by a level of hybrid fertility. Hybridization has been frequent in this species since the first millennium BCE. It was common for nearly one thousand years to breed the two species in order to create a stronger camel.
Protylopus, the smallest and oldest of camel species, lived in North America during the Eocene period. These camels traveled across the Bering Strait during the Pliocene ear to the Pleistocene era. They moved into Asia, Africa, and Eastern Europe, and from these, the ancestors of the dromedary camel appeared in North Africa and the Middle East.
Throughout history, the dromedary camel has been used to carry objects and humans. In the Bible, the dromedary camel was used in the second millennium BCE by nomadic tribes, but experts do not consider this a fact. This camel is thought to have spread across its range beginning in the first century, before Romans appeared. In 525 BC Persian camel were introduced into the dromedary camel range, when the Persians invaded Egypt under the rule of Cambyses. The Persian camels, however, were not accustomed to the arid Sahara and so any long-term travel or trade required horses.
After Islamic invaders conquered North Africa, the dromedary camels were a common site. This was due to the new connection to the Middle East, although the invasion was conducted mostly on horseback. Because of the strength and resilience of these camels, trade grew across the Sahara. It was used for transportation of milk and humans in Libya, restricted to the country during this time. In 547 CE, King Cyrus the Great used the dromedary camel while fighting king Croesus of Lydia and this was the first time the camels were used in war. After this, many regions and people used the camels in warfare, including the Persians and Alexander the Great, and the eastern regions of Egypt, Syria, and Arabia among other areas.
The dromedary camel was introduced from Canary Islands to Adelaide in Australia in 1840, but only one camel made it through the trip. Through 1840 and 1907, many camels were imported to Australia, in order to open up the dry western and central areas of the country. John Horrocks was the first person to use these camels for exploration in Australia. Because of this introduction into Australia, feral camels descended from domesticated dromedaries now number nearly one million. The domestication of the dromedary camel occurred in southern or central Arabia, perhaps around four thousand years ago. Now there are over thirteen million domesticated dromedary camels within its range, although no wild individuals exist in its natural range.
The dromedary camel is one of the largest camel species, with males reaching an average height of up to 6.6 feet and females reaching up to 6.2 feet. Males can weigh up to 1,300 pounds, ten percent more than females. The coloring of these camels can vary between black to light brown or tan, with more hair appearing on the hump, neck, and shoulders. Males not only differ in size, but also bare a pink glandular sac in the mouth that can be mistaken for a tongue. This is used to attract females during mating season and is known in Arabic as a “doula”. The camels also have thick eyelashes and two flat toes on each foot.
The hump of the dromedary camel is large, reaching a height of 7.9 feet on average. The hump is made of fat and is held together by fibrous tissues. These camels can withstand body temperature variances between 93.2 degrees and 1.7 degrees Fahrenheit, allowing for better water conservation. Instead of walking with one leg on each side of the body, the dromedary camel walks with two legs on each side of the body at one time. It can live up to forty years on average, but can live fifty years in captivity.
The dromedary camel has many adaptations that allow it to live in its arid range. Its thick eyelashes provide safety from blowing sand, as well the ability to close its nostrils. Besides the ability to regulate its temperature for water conservation, the dromedary camel has kidneys that excrete as little water as possible. Individuals will group together to regulate body temperature as well.
It is commonly known that camels can go many days without water, but the dromedary camel can go months without water in the Sahara, between October and April or May. However, when temperatures reach between 86 and 104 degrees Fahrenheit, it needs water every ten to fifteen days. The fatty hump on the back of this camel is used for storing energy and water. When water is needed, the fat is broken down, but camels with smaller humps can display symptoms of starvation.
The dromedary camel will gather in groups of around twenty in the summer time, resting close together in order regulate a cool body temperature. A male typically leads these groups, although females do get a turn to lead as well. Males will sometimes form all male bachelor groups, or travel alone. The small groups will larger herds numbering up to hundreds of camels, especially during troubling times or when searching for a drink of water. Aggression does not commonly occur, except during mating season, when males turn on each other and will bite, kick, and wrestle to defend the females in the each smaller group.
The breeding season for the dromedary camel typically occurs during winter, with a peak occurring in the rainy season. It is thought that mating coincides with the length of the days and with the level of nutrition of each camel. There is a follicle on females that grows when the estrous cycle occurs, but this will disappear if the females do not mate within a few days of this cycle. By studying this follicle, it was found that the best time to conceive a baby camel is when the follicle reaches between 0.35 and 0.75 inches.
When mating season begins, males will use their tails to spread urine across the back and lower ends of their bodies. The pink palate, or glandular sac, is released and foam covers the entire mouth. Males fight for dominance over females by displaying height, with both males attempting to stand taller than the other. Once mating begins, the male will force the female to sit. Often times, the people looking over the camels will aid the male in successfully mating, although the camels do not heed the help.
After a pregnancy period of about fifteen months, one calf is born that is able to walk and nurse by the end of its first day. Young camels will remain with their mothers until at least two years of age. One study focused on feeding baby camels milk substitutes, specifically those made for lambs by the Mabarot Chemical and Veterinary Products in Israel. Two baby camels, each a one-month-old male, were chosen for the study, and removed from their mothers. After one month of feeding the baby camels the substitute, their weights were recorded and they were found to be healthy.
Dromedary camels display some odd social behaviors, including biting without actually using teeth. When irritated, these camels will stamp their feet and run, and they can be seen spitting cud when excited or injured. The camels will use their hind or fore feet, as well as their incisors to scratch any itches, but can be seen rubbing against sand or trees to alleviate itches as well. When traveling in groups, the camels will walk in a single file line. The most commonly heard vocalizations of this species include the gurgle of rutting males, a threatening whistle made by males, and bleat that helps locate other camels. Most camels can remember where their home is located, but females are especially skilled at this, and can locate the first place they gave birth or nursed their first calf.
The diet of the dromedary camel consists of desert plants, foliage, and dry grasses. Thorny vegetation comprised nearly seventy percent of its summer diet, and ninety percent of its winter diet. There have been over 320-recorded plants in the dromedary’s diet, although Santalum acuminatum, Erythrina vespertilio, and Lawrencia species are among the preferred plant types.
Thorny plants are consumed with the lips open, and chewed between forty to fifty times. A study conducted in Ethiopia found that most dromedary camels spent the majority of the day grazing, although this was prominent in young camels and occurred mainly in the dry season. During the rainy season, the camels spent more time resting or doing other activities.
Dromedary camels are used for many things, including food and transportation of goods. The hair of these camels can be used as material for tents and clothing. The milk of this species is important to desert nomadic tribes, because it holds more nutrients than cow’s milk and can keep better at higher temperatures. These camels can produces between 7.7 and 77 pounds of milk a day, with amounts dependent upon the region in which they live, as well as the health and living conditions of each camel. A healthy female camel typically produces up to twenty pounds of milk a day. The ability to curd this camel’s milk was tested, and found to be more difficult than curding cow’s milk. However, cheese and other dairy foods are created form camel’s milk, and there is a factory in Nouakchott that specialized in pasteurizing camel’s milk to make cheese.
Dromedary camels also provide a good source of meat for humans within its range, and have a taste and texture similar to that of beef. The meat is typically processed into burgers, sausages, patties, and shawarma. Not every part of the camel is safe for consumption. A study conducted by the United States Centers for Disease Control and Prevention and the Saudi Ministry of Health in 2005 showed that the bubonic plague was present in some camel livers, which were consumed raw. Four of five people studied displayed severe pharyngitis, or sore throat, as well as submandibular lymphadenitis.
The dromedary camel is highly susceptible to a parasitic disease known as trypanosomiasis, which is caused from Trypanosoma evansi, T. brucei, T. congolense, and T. simiae. It can be contracted from Tabinidae species and Glossina species. The symptoms of this disease include weakness, anemia, and recurring fever and camels afflicted with the disease typically die. Another disease that dromedaries can contract is Brucellosis. This disease occurs more often in camels that are kept in higher numbers than in camels that are nomadic.
In central Somalia, 1,039 camels from thirty-three different groups were studied 2.2 percent of the camels were found to have Brucellosis. Other parasites that the camels had contracted include T. evansi, Trichuris, and Strongyloides, among many others. Mange, an external parasite, was also prevalent. Surprisingly, dromedary camels in studied in Ethiopia after an outbreak of the rinderpest virus were found to have a natural antibody to the virus, as well as an antibody to the ovine rinderpest, also known as peste des petits ruminants or PPR.
The dromedary camel can have fleas and ticks, with both species holding the possibility to carry disease. These species include ticks like Hyalomma and Rhipicephalus and fleas like Vermipsylla alakurt. These species cause physical irritation. Other species are more dangerous to the dromedaries, like Cephalopsis titillator larvae, which can cause nervous disorders, brain compression, and death. A study conducted in Egypt focused on the number of fleas and ticks found on camels. Of the 2,545 ticks found, 1,491 were adults while 1,054 ticks were nymphs, or baby ticks. All nymphs and 95.6 percent of adults occurring on the camels were of the Hyalomma dromedarii species, with all other species being either a subspecies of H. marginatum or H. anatolicum excavatum. The number of ticks occurring on each camel numbered between 6 and 173.
Image Caption: Dromedary camel in outback Australia, near Silverton, NSW. Credit: Jjron/Wikipedia (CC BY-SA 3.0)