Arabian Camel on:
[Wikipedia]
[Google]
[Amazon]
Largest species of camel
/ref> females range between . Males typically weigh between ; females range between . The distinctive features are its long, curved neck, narrow chest, and single hump (the Bactrian camel has two), thick, double-layered eyelashes, and bushy eyebrows. They have sharp vision and a good sense of smell. The male has a soft palate ( in Arabic) nearly long, which he inflates to produce a deep pink sac. The palate, which is often mistaken for the tongue, dangles from one side of the mouth and is used to attract females during the mating season. The coat is generally brown, but can range from black to nearly white. Leese reported piebald dromedaries in Kordofan and Darfur in Sudan. Piebald coloration in some camels is thought to be caused by the ''KITW1'' allele of the ''KIT'' gene, though at least one other mutation likely also causes white spotting. The hair is long and concentrated on the throat, shoulders, and hump. The large eyes are protected by prominent supraorbital ridges; the ears are small and rounded. The hump is at least high. The dromedary has long, powerful legs with two toes on each foot. The feet resemble flat, leathery pads. Like the giraffe, dromedaries move both legs on one side of the body at the same time. Compared with the Bactrian camel, the dromedary has a lighter build, longer limbs, shorter hairs, a harder palate, and an insignificant or absent ethmoidal fissure. Unlike the camelids of the genus ''Lama'', the dromedary has a hump, and in comparison has a longer tail, smaller ears, squarer feet, and a greater height at the shoulder. The dromedary has four teats instead of the two in the ''Lama'' species.
The cranium of the dromedary consists of a postorbital bar, a tympanic bulla filled with spongiosa, a well-defined sagittal crest, a long facial part and an indented nasal bone. Typically, there are eight sternal and four non-sternal pairs of ribs. The spinal cord is nearly long; it terminates in the second and third sacral vertebra. The fibula is reduced to a malleolar bone. The dromedary is a digitigrade animal; it walks on its toes, which are known as digits. It lacks the second and fifth digits. The front feet are wide and long; they are larger than the hind feet, which measure wide and long.
The dromedary has 22 milk teeth, which are eventually replaced by 34 permanent teeth. The dental formula for permanent dentition is , and for
The dromedary (''Camelus dromedarius''), also known as the dromedary camel, Arabian camel and one-humped camel, is a large
Bactrian; the word came into English via Old Norman">Bactrian camel">Bactrian; the word came into English via Old Norman, from the Latin">Old_Norman.html" ;"title="Bactrian camel">Bactrian; the word came into English via Old Norman">Bactrian camel">Bactrian; the word came into English via Old Norman, from the Latin word ', from Ancient Greek ('), ultimately from a Semitic language, Semitic source akin to Hebrew language, Hebrew (') and Arabic language, Arabic (').
camel
A camel (from and () from Ancient Semitic: ''gāmāl'') is an even-toed ungulate in the genus ''Camelus'' that bears distinctive fatty deposits known as "humps" on its back. Camels have long been domesticated and, as livestock, they provid ...
of the genus '' Camelus'' with one hump on its back. It is the tallest of the three camel species; adult males stand at the shoulder, while females are tall. Males typically weigh between , and females weigh between .
The dromedary's distinctive features include its long, curved neck, narrow chest, a single hump, and long hairs on the throat, shoulders, and hump. The coat is generally a shade of brown. The hump, tall or more, is made of fat bound together by fibrous tissue.
The dromedary feeds on foliage and desert vegetation; several adaptations, such as the ability to tolerate losing more than 30% of its total water content, allow it to thrive in its desert habitat. Mating occurs annually and peaks in the rainy season; females bear a single calf after a gestation
Gestation is the period of development during the carrying of an embryo, and later fetus, inside viviparous animals (the embryo develops within the parent). It is typical for mammals, but also occurs for some non-mammals. Mammals during pregn ...
of 15 months. It is mainly active during daylight hours and forms herds of about 20 individuals, which are led by a dominant male.
The dromedary has not occurred naturally in the wild for nearly 2,000 years. It was probably first domesticated in the Arabian Peninsula
The Arabian Peninsula (, , or , , ) or Arabia, is a peninsula in West Asia, situated north-east of Africa on the Arabian plate. At , comparable in size to India, the Arabian Peninsula is the largest peninsula in the world.
Geographically, the ...
about 4,000 years ago, or in Somalia
Somalia, officially the Federal Republic of Somalia, is the easternmost country in continental Africa. The country is located in the Horn of Africa and is bordered by Ethiopia to the west, Djibouti to the northwest, Kenya to the southwest, th ...
where paintings of it found in Laas Geel date from 5,000 to 9,000 years ago. In the wild, the dromedary inhabited arid regions, including the Sahara
The Sahara (, ) is a desert spanning across North Africa. With an area of , it is the largest hot desert in the world and the list of deserts by area, third-largest desert overall, smaller only than the deserts of Antarctica and the northern Ar ...
. The domesticated dromedary is generally found in the semiarid to arid regions of the Old World, mainly in Africa and the Arabian Peninsula, and a significant feral population occurs in Australia. Products of the dromedary, including its meat and milk, support several North African tribes; it is also commonly used for riding and as a pack animal.
Etymology
The common name "dromedary" comes from theOld French
Old French (, , ; ) was the language spoken in most of the northern half of France approximately between the late 8th -4; we might wonder whether there's a point at which it's appropriate to talk of the beginnings of French, that is, when it wa ...
' or the Late Latin . These originated from the Greek word , (genitive">GEN (γενική) ', ), meaning "running" or "runner",. used in Greek in the combination (), literally "running camel", to refer to the dromedary. The first recorded use in English of the name "dromedary" occurred in the 14th century. The dromedary possibly originated in Arabia or Somalia, so is sometimes referred to as the Arabian or East African camel. The word "camel" generally refers either to the dromedary or the congeneric
Congener may refer to:
* Congener (biology), organisms within the same genus
* Congener (chemistry), related chemicals, e.g., elements in the same group of the periodic table
* Congener (beverages), a substance other than ethanol produced during t ...Taxonomy and classification
The dromedary shares thegenus
Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
'' Camelus'' with the Bactrian camel (''C. bactrianus'') and the wild Bactrian camel (''C. ferus''). The dromedary belongs to the family Camelidae. Ancient Greek
Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...
philosopher Aristotle
Aristotle (; 384–322 BC) was an Ancient Greek philosophy, Ancient Greek philosopher and polymath. His writings cover a broad range of subjects spanning the natural sciences, philosophy, linguistics, economics, politics, psychology, a ...
(fourth century BC) was the first to describe the species of ''Camelus''. He named two species in his '' History of Animals''; the one-humped Arabian camel and the two-humped Bactrian camel. The dromedary was given its current binomial name ''Camelus dromedarius'' by Swedish zoologist Carl Linnaeus
Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...
in his 1758 publication ''Systema Naturae
' (originally in Latin written ' with the Orthographic ligature, ligature æ) is one of the major works of the Sweden, Swedish botanist, zoologist and physician Carl Linnaeus (1707–1778) and introduced the Linnaean taxonomy. Although the syste ...
''. In 1927, British veterinarian Arnold Leese classified dromedaries by their basic habitats; the hill camels are small, muscular animals and efficient beasts of burden; the larger plains camels could be further divided into the desert type that can bear light burdens and are apt for riding, and the riverine type – slow animals that can bear heavy burdens; and those intermediate between these two types.
In 2007, Peng Cui of the Chinese Academy of Sciences
The Chinese Academy of Sciences (CAS; ) is the national academy for natural sciences and the highest consultancy for science and technology of the People's Republic of China. It is the world's largest research organization, with 106 research i ...
and colleagues carried out a phylogenetic
In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...
study of the evolutionary relationships between the two tribes of Camelidae; Camelini – consisting of the three ''Camelus'' species (the study considered the wild Bactrian camel as a subspecies
In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...
of the Bactrian camel) – and Lamini, which consists of the alpaca (''Vicugna pacos''), the guanaco (''Lama guanicoe''), the llama
The llama (; or ) (''Lama glama'') is a domesticated South American camelid, widely used as a List of meat animals, meat and pack animal by Inca empire, Andean cultures since the pre-Columbian era.
Llamas are social animals and live with ...
(''L. glama''), and the vicuña
The vicuña (''Lama vicugna'') or vicuna (both , very rarely spelled ''vicugna'', Vicugna, its former genus name) is one of the two wild South American camelids, which live in the high alpine tundra, alpine areas of the Andes; the other cameli ...
(''V. vicugna''). The study showed the two tribes had diverged 25 million years ago (early Miocene
The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...
), earlier than previously estimated from North American fossils.
The dromedary and the Bactrian camels often interbreed to produce fertile offspring. Where the ranges of the species overlap, such as in northern Punjab, Persia, and Afghanistan, the phenotypic differences between them tend to decrease as a result of extensive crossbreeding. The fertility of their hybrid has given rise to speculation that the dromedary and the Bactrian camel should be merged into a single species with two varieties. However, a 1994 analysis of the mitochondrial cytochrome b gene
In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...
showed the species display 10.3% divergence in their sequences.
Genetics and hybrids
The dromedary has 74 diploid chromosomes, the same as other camelids. The autosomes consist of five pairs of small to medium-sized metacentrics and submetacentrics. The X chromosome is the largest in the metacentric and submetacentric group. There are 31 pairs of acrocentrics. The dromedary'skaryotype
A karyotype is the general appearance of the complete set of chromosomes in the cells of a species or in an individual organism, mainly including their sizes, numbers, and shapes. Karyotyping is the process by which a karyotype is discerned by de ...
is similar to that of the Bactrian camel.
Camel hybridization began in the first millennium BC. For about a thousand years, Bactrian camels and dromedaries have been successfully bred in regions where they are sympatric to form hybrids with either a long, slightly lopsided hump or two humps – one small and one large. These hybrids are larger and stronger than their parents – they can bear greater loads. A cross between a first-generation female hybrid and a male Bactrian camel can also produce a hybrid. Hybrids from other combinations tend to be bad-tempered or runts.
Evolution
The extinct '' Protylopus'', which occurred in North America during the upperEocene
The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...
, is the oldest and the smallest-known camel. During the transition from Pliocene
The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58Pleistocene
The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...
, several mammals faced extinction. This period marked the successful radiation of the ''Camelus'' species, which migrated over the Bering Strait and dispersed widely into Asia, eastern Europe, and Africa. By the Pleistocene, ancestors of the dromedary occurred in the Middle East and northern Africa.
The modern dromedary probably evolved in the hotter, arid regions of western Asia from the Bactrian camel, which in turn was closely related to the earliest Old World camels. This hypothesis was once thought to be supported by the dromedary foetus having two humps, but modern studies have shown this to be false. A jawbone of a dromedary that dated from 8,200 BC was found in Saudi Arabia on the southern coast of the Red Sea
The Red Sea is a sea inlet of the Indian Ocean, lying between Africa and Asia. Its connection to the ocean is in the south, through the Bab-el-Mandeb Strait and the Gulf of Aden. To its north lie the Sinai Peninsula, the Gulf of Aqaba, and th ...
.
In 1975, Richard Bulliet of Columbia University
Columbia University in the City of New York, commonly referred to as Columbia University, is a Private university, private Ivy League research university in New York City. Established in 1754 as King's College on the grounds of Trinity Churc ...
wrote that the dromedary exists in large numbers in areas from which the Bactrian camel has disappeared; the converse is also true to a great extent. He said this substitution could have taken place because of the heavy dependence on the milk, meat, and wool of the dromedary by Syrian and Arabian nomads, while the Asiatic people domesticated the Bactrian camel, but did not have to depend upon its products.
Characteristics
The dromedary is the tallest of the three camel species. Adult males range in height between at the shoulder;Guinness World Records
''Guinness World Records'', known from its inception in 1955 until 1999 as ''The Guinness Book of Records'' and in previous United States editions as ''The Guinness Book of World Records'', is a British reference book published annually, list ...
Largest species of camel
/ref> females range between . Males typically weigh between ; females range between . The distinctive features are its long, curved neck, narrow chest, and single hump (the Bactrian camel has two), thick, double-layered eyelashes, and bushy eyebrows. They have sharp vision and a good sense of smell. The male has a soft palate ( in Arabic) nearly long, which he inflates to produce a deep pink sac. The palate, which is often mistaken for the tongue, dangles from one side of the mouth and is used to attract females during the mating season. The coat is generally brown, but can range from black to nearly white. Leese reported piebald dromedaries in Kordofan and Darfur in Sudan. Piebald coloration in some camels is thought to be caused by the ''KITW1'' allele of the ''KIT'' gene, though at least one other mutation likely also causes white spotting. The hair is long and concentrated on the throat, shoulders, and hump. The large eyes are protected by prominent supraorbital ridges; the ears are small and rounded. The hump is at least high. The dromedary has long, powerful legs with two toes on each foot. The feet resemble flat, leathery pads. Like the giraffe, dromedaries move both legs on one side of the body at the same time. Compared with the Bactrian camel, the dromedary has a lighter build, longer limbs, shorter hairs, a harder palate, and an insignificant or absent ethmoidal fissure. Unlike the camelids of the genus ''Lama'', the dromedary has a hump, and in comparison has a longer tail, smaller ears, squarer feet, and a greater height at the shoulder. The dromedary has four teats instead of the two in the ''Lama'' species.
Anatomy
The cranium of the dromedary consists of a postorbital bar, a tympanic bulla filled with spongiosa, a well-defined sagittal crest, a long facial part and an indented nasal bone. Typically, there are eight sternal and four non-sternal pairs of ribs. The spinal cord is nearly long; it terminates in the second and third sacral vertebra. The fibula is reduced to a malleolar bone. The dromedary is a digitigrade animal; it walks on its toes, which are known as digits. It lacks the second and fifth digits. The front feet are wide and long; they are larger than the hind feet, which measure wide and long.
The dromedary has 22 milk teeth, which are eventually replaced by 34 permanent teeth. The dental formula for permanent dentition is , and for milk
Milk is a white liquid food produced by the mammary glands of lactating mammals. It is the primary source of nutrition for young mammals (including breastfeeding, breastfed human infants) before they are able to digestion, digest solid food. ...
dentition. In the juvenile, the lower first molars
The molars or molar teeth are large, flat tooth, teeth at the back of the mouth. They are more developed in mammal, mammals. They are used primarily to comminution, grind food during mastication, chewing. The name ''molar'' derives from Latin, '' ...
develop by 12 to 15 months and the permanent lower incisors appear at 4.5 to 6.5 years of age. All teeth are in use by 8 years. The lenses of the eyes contain crystallin, which constitutes 8 to 13% of the protein present there.
The skin is black; the epidermis
The epidermis is the outermost of the three layers that comprise the skin, the inner layers being the dermis and Subcutaneous tissue, hypodermis. The epidermal layer provides a barrier to infection from environmental pathogens and regulates the ...
is thick and the dermis
The dermis or corium is a layer of skin between the epidermis (skin), epidermis (with which it makes up the cutis (anatomy), cutis) and subcutaneous tissues, that primarily consists of dense irregular connective tissue and cushions the body from s ...
is thick. The hump is composed of fat bound together by fibrous tissue. There are no glands on the face; males have glands that appear to be modified apocrine sweat glands that secrete pungent, coffee-coloured fluid during the rut, located on either side of the neck midline. The glands generally grow heavier during the rut, and range from . Each cover hair is associated with an arrector pilli muscle, a hair follicle, a ring of sebaceous glands and a sweat gland. Females have cone-shaped, four-chambered mammary gland
A mammary gland is an exocrine gland that produces milk in humans and other mammals. Mammals get their name from the Latin word ''mamma'', "breast". The mammary glands are arranged in organs such as the breasts in primates (for example, human ...
s that are long with a base diameter of . These glands can produce milk with up to 90% water content even if the mother is at risk of dehydration.
The heart weighs around ; it has two ventricles with the tip curving to the left. The pulse rate is 50 beats per minute. The dromedary is the only mammal with oval red blood corpuscles, which facilitates blood flow during dehydration. The pH of the blood varies from 7.1 to 7.6 (slightly alkaline). The individual's state of hydration and sex and the time of year can influence blood values. The lung
The lungs are the primary Organ (biology), organs of the respiratory system in many animals, including humans. In mammals and most other tetrapods, two lungs are located near the Vertebral column, backbone on either side of the heart. Their ...
s lack lobes. A dehydrated camel has a lower breathing rate. Each kidney has a capacity of , and can produce urine with high chloride concentrations. Like the horse, the dromedary has no gall bladder. The grayish violet, crescent-like spleen weighs less than . The triangular, four-chambered liver weighs ; its dimensions are .
Reproductive system
Theovaries
The ovary () is a gonad in the female reproductive system that produces ova; when released, an ovum travels through the fallopian tube/oviduct into the uterus. There is an ovary on the left and the right side of the body. The ovaries are endocr ...
are reddish, circular and flattened. They are enclosed in a conical bursa and have the dimensions during anestrus. The oviducts are long. The uterus
The uterus (from Latin ''uterus'', : uteri or uteruses) or womb () is the hollow organ, organ in the reproductive system of most female mammals, including humans, that accommodates the embryonic development, embryonic and prenatal development, f ...
is bicornuate. The vagina
In mammals and other animals, the vagina (: vaginas or vaginae) is the elastic, muscular sex organ, reproductive organ of the female genital tract. In humans, it extends from the vulval vestibule to the cervix (neck of the uterus). The #Vag ...
is long and has well-developed Bartholin's glands. The vulva
In mammals, the vulva (: vulvas or vulvae) comprises mostly external, visible structures of the female sex organ, genitalia leading into the interior of the female reproductive tract. For humans, it includes the mons pubis, labia majora, lab ...
is deep and has a small clitoris
In amniotes, the clitoris ( or ; : clitorises or clitorides) is a female sex organ. In humans, it is the vulva's most erogenous zone, erogenous area and generally the primary anatomical source of female Human sexuality, sexual pleasure. Th ...
. The placenta is diffuse and epitheliochorial, with a crescent-like chorion.
The penis
A penis (; : penises or penes) is a sex organ through which male and hermaphrodite animals expel semen during copulation (zoology), copulation, and through which male placental mammals and marsupials also Urination, urinate.
The term ''pen ...
is covered by a triangular penile sheath that opens backwards; it is about long. The scrotum is located high in the perineum
The perineum (: perineums or perinea) in placentalia, placental mammals is the space between the anus and the genitals. The human perineum is between the anus and scrotum in the male or between the anus and vulva in the female. The perineum is ...
with the testicles in separate sacs. Testicles are long, deep and wide. The right testicle is often smaller than the left. The typical mass of either testicle is less than ; during the rut the mass increases from . The Cowper's gland is white, almond-shaped and lacks seminal vesicles; the prostate gland
The prostate is an male accessory gland, accessory gland of the male reproductive system and a muscle-driven mechanical switch between urination and ejaculation. It is found in all male mammals. It differs between species anatomically, chemica ...
is dark yellow, disc-shaped and divided into two lobes.
The camel epididymis interstitium revealed several blood vessels harboring special regulatory devices such as the spiral arteries, spiral veins, and throttle arterioles.
Health and diseases
The dromedary generally suffers from fewer diseases than other domestic livestock such as goats and cattle. Temperature fluctuations occur throughout the day in a healthy dromedary – the temperature falls to its minimum at dawn, rises until sunset and falls during the night. Nervous camels may vomit if they are carelessly handled; this does not always indicate a disorder. Rutting males may develop nausea. The dromedary is prone to trypanosomiasis, a disease caused by a parasite transmitted by the tsetse fly. The main symptoms are recurring fever, anaemia and weakness; the disease is typically fatal for the camel. Brucellosis is another prominent malady. In an observational study, theseroprevalence
Seroprevalence is the number of persons in a population who test positive for a specific disease based on serology (blood serum) specimens, often presented as a percent of the total specimens tested or as a proportion per 100,000 persons tested. As ...
of this disease was generally low (2 to 5%) in nomadic or moderately free dromedaries, but it was higher (8 to 15%) in denser populations. Brucellosis is caused by different biotype
{{Short pages monitor