Camelids are members of the biological
family
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
Camelidae, the only currently living family in the suborder
Tylopoda
Tylopoda (meaning "calloused foot") is a suborder of terrestrial herbivorous even-toed ungulates belonging to the order Artiodactyla. They are found in the wild in their native ranges of South America and Asia, while Australian feral camels ...
. The seven
extant
Extant is the opposite of the word extinct. It may refer to:
* Extant hereditary titles
* Extant literature, surviving literature, such as ''Beowulf'', the oldest extant manuscript written in English
* Extant taxon, a taxon which is not extinct, ...
members of this group are:
dromedary camels,
Bactrian camel
The Bactrian camel (''Camelus bactrianus''), also known as the Mongolian camel or domestic Bactrian camel, is a large even-toed ungulate native to the steppes of Central Asia. It has two humps on its back, in contrast to the single-humped dro ...
s,
wild Bactrian camel
The wild Bactrian camel (''Camelus ferus'') is a critically endangered species of camel living in parts of northwestern China and southwestern Mongolia. It is closely related to the Bactrian camel (''Camelus bactrianus''). Both are large, doubl ...
s,
llama
The llama (; ) (''Lama glama'') is a domesticated South American camelid, widely used as a meat and pack animal by Andean cultures since the Pre-Columbian era.
Llamas are social animals and live with others as a herd. Their wool is soft ...
s,
alpaca
The alpaca (''Lama pacos'') is a species of South American camelid mammal. It is similar to, and often confused with, the llama. However, alpacas are often noticeably smaller than llamas. The two animals are closely related and can success ...
s,
vicuñas, and
guanacos. Camelids are
even-toed ungulates
The even-toed ungulates (Artiodactyla , ) are ungulates—hoofed animals—which bear weight equally on two (an even number) of their five toes: the third and fourth. The other three toes are either present, absent, vestigial, or pointing poste ...
classified in the
order
Order, ORDER or Orders may refer to:
* Categorization, the process in which ideas and objects are recognized, differentiated, and understood
* Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of ...
Cetartiodactyla
The even-toed ungulates (Artiodactyla , ) are ungulates—hoofed animals—which bear weight equally on two (an even number) of their five toes: the third and fourth. The other three toes are either present, absent, vestigial, or pointing poste ...
, along with species like
whale
Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. all cetaceans apart from dolphins and ...
s,
pigs
The pig (''Sus domesticus''), often called swine, hog, or domestic pig when distinguishing from other members of the genus '' Sus'', is an omnivorous, domesticated, even-toed, hoofed mammal. It is variously considered a subspecies of ''Sus ...
,
deer
Deer or true deer are hoofed ruminant mammals forming the family Cervidae. The two main groups of deer are the Cervinae, including the muntjac, the elk (wapiti), the red deer, and the fallow deer; and the Capreolinae, including the re ...
,
cattle
Cattle (''Bos taurus'') are large, domesticated, cloven-hooved, herbivores. They are a prominent modern member of the subfamily Bovinae and the most widespread species of the genus '' Bos''. Adult females are referred to as cows and adult ...
, and
antelope
The term antelope is used to refer to many species of even-toed ruminant that are indigenous to various regions in Africa and Eurasia.
Antelope comprise a wastebasket taxon defined as any of numerous Old World grazing and browsing hoofed mamm ...
s.
Characteristics
Camelids are large, strictly
herbivorous animals with slender necks and long legs. They differ from
ruminants in a number of ways.
[Fowler, M.E. (2010). ''Medicine and Surgery of Camelids'', Ames, Iowa: Wiley-Blackwell. Chapter 1 "General Biology and Evolution" addresses the fact that camelids (including camels and llamas) are not ruminants, pseudo-ruminants, or modified ruminants.] Their dentition show traces of vestigial central
incisor
Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, wher ...
s in the
incisive bone, and the third incisors have developed into canine-like tusks. Camelids also have true
canine teeth and tusk-like
premolars, which are separated from the
molars by a gap. The musculature of the hind limbs differs from those of other ungulates in that the legs are attached to the body only at the top of the thigh, rather than attached by skin and muscle from the knee upwards. Because of this, camelids have to lie down by resting on their knees with their legs tucked underneath their bodies.
They have three-chambered
stomach
The stomach is a muscular, hollow organ in the gastrointestinal tract of humans and many other animals, including several invertebrates. The stomach has a dilated structure and functions as a vital organ in the digestive system. The stomach i ...
s, rather than four-chambered ones; their upper lips are split in two, with each part separately mobile; and, uniquely among mammals, their
red blood cell
Red blood cells (RBCs), also referred to as red cells, red blood corpuscles (in humans or other animals not having nucleus in red blood cells), haematids, erythroid cells or erythrocytes (from Greek ''erythros'' for "red" and ''kytos'' for "hol ...
s are elliptical.
They also have a unique type of
antibodies
An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of ...
, which lack the light chain, in addition to the normal antibodies found in other mammals. These so-called
heavy-chain antibodies
A heavy-chain antibody is an antibody which consists only of two heavy chains and lacks the two light chains usually found in antibodies.
In common antibodies, the antigen binding region consists of the variable domains of the heavy and light c ...
are being used to develop
single-domain antibodies with potential
pharmaceutical
A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy ( pharmacotherapy) is an important part of the medical field and ...
applications.
Camelids do not have hooves; rather, they have two-toed feet with toenails and soft foot pads (
Tylopoda
Tylopoda (meaning "calloused foot") is a suborder of terrestrial herbivorous even-toed ungulates belonging to the order Artiodactyla. They are found in the wild in their native ranges of South America and Asia, while Australian feral camels ...
is Greek for "padded foot"). Most of the weight of the animal rests on these tough, leathery sole pads. The South American camelids have adapted to the steep and rocky terrain by adjusting the pads on their toes to maintain grip.
The surface area of Camels foot pads can increase with increasing velocity in order to reduce pressure on the feet and larger members of the camelid species will usually have larger pad area to help distribute weight across the foot. Many fossil camelids were
unguligrade and probably hooved, in contrast to all living species.
Camelids are behaviorally similar in many ways, including their walking gait, in which both legs on the same side are moved simultaneously. While running, camelids engage a unique "running pace gait" in which limbs on the same side move in the same pattern they walk, with both left legs moving and then both right, this ensures that the fore and hind limb will not collide while in fast motion. During this motion there is a moment where all four limbs are off the ground at the same time. Consequently, camelids large enough for human beings to ride have a typical swaying motion.
Dromedary camels, bactrian camels, llamas, and alpacas are all
induced ovulators.
The three Afro-Asian camel species have developed extensive adaptations to their lives in harsh, near-waterless environments. Wild populations of the Bactrian camel are even able to drink
brackish water
Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estuari ...
, and some herds live in nuclear test areas.
Comparative table of the seven extant species in the family Camelidae:
Evolution
Camelids are unusual in that their modern distribution is almost the inverse of their area of origin. Camelids first appeared very early in the evolution of the even-toed ungulates, around 50 to 40 million years ago during the middle
Eocene
The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', ...
, in present-day
North America
North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and th ...
. Among the earliest camelids was the rabbit-sized ''
Protylopus
''Protylopus'' is an extinct genus of camel that lived during middle to late Eocene some 50-40 million years ago in North America.
Along with being the oldest camel known, it was also the smallest, reaching a length of , and probably weighing a ...
'', which still had four toes on each foot. By the late
Eocene
The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', ...
, around 35 million years ago, camelids such as ''
Poebrotherium
''Poebrotherium'' ( ) is an extinct genus of camelid, endemic to North America. They lived from the Eocene to Miocene epochs, 46.3—13.6 mya, existing for approximately .
Discovery and history
''Poebrotherium'' was first named by scientist ...
'' had lost the two lateral toes, and were about the size of a modern
goat
The goat or domestic goat (''Capra hircus'') is a domesticated species of goat-antelope typically kept as livestock. It was domesticated from the wild goat (''C. aegagrus'') of Southwest Asia and Eastern Europe. The goat is a member of the a ...
.
[
The family diversified and prospered, but remained confined to the North American continent until only about two to three million years ago, when representatives arrived in ]Asia
Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an are ...
, and (as part of the Great American Interchange
The Great American Biotic Interchange (commonly abbreviated as GABI), also known as the Great American Interchange and the Great American Faunal Interchange, was an important late Cenozoic paleozoogeographic biotic interchange event in which lan ...
that followed the formation of the Isthmus of Panama
The Isthmus of Panama ( es, Istmo de Panamá), also historically known as the Isthmus of Darien (), is the narrow strip of land that lies between the Caribbean Sea and the Pacific Ocean, linking North and South America. It contains the country ...
) South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sou ...
. A high arctic camel from this time period has been documented in the far northern reaches of Canada.
The original camelids of North America remained common until the quite recent geological past, but then disappeared, possibly as a result of hunting or habitat alterations by the earliest human settlers, and possibly as a result of changing environmental conditions after the last ice age, or a combination of these factors. Three species groups survived: the dromedary
The dromedary (''Camelus dromedarius'' or ;), also known as the dromedary camel, Arabian camel, or one-humped camel, is a large even-toed ungulate, of the genus '' Camelus'', with one hump on its back.
It is the tallest of the three species o ...
of northern Africa
Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...
and southwest Asia; the Bactrian camel
The Bactrian camel (''Camelus bactrianus''), also known as the Mongolian camel or domestic Bactrian camel, is a large even-toed ungulate native to the steppes of Central Asia. It has two humps on its back, in contrast to the single-humped dro ...
of central Asia; and the South American group, which has now diverged into a range of forms that are closely related, but usually classified as four species: llama
The llama (; ) (''Lama glama'') is a domesticated South American camelid, widely used as a meat and pack animal by Andean cultures since the Pre-Columbian era.
Llamas are social animals and live with others as a herd. Their wool is soft ...
s, alpaca
The alpaca (''Lama pacos'') is a species of South American camelid mammal. It is similar to, and often confused with, the llama. However, alpacas are often noticeably smaller than llamas. The two animals are closely related and can success ...
s, guanacos, and vicuñas. Camelids were domesticated by early Andean peoples, and remain in use today.
Fossil camelids show a wider variety than their modern counterparts. One North American genus, '' Titanotylopus'', stood 3.5 m at the shoulder, compared with about 2 m for the largest modern camelids. Other extinct camelids included small, gazelle-like animals, such as ''Stenomylus
''Stenomylus'' is an extinct genus of miniature camelid native to North America that died out around 30 million years ago. Its name is derived from the Greek (, "narrow") and (, "molar").
''Stenomylus'' was extremely diminutive compared to ...
''. Finally, a number of very tall, giraffe-like camelids were adapted to feeding on leaves from high trees, including such genera as '' Aepycamelus'' and '' Oxydactylus''.[
Whether the wild Bactrian camel (''Camelus ferus'') is in fact a distinct species or a subspecies (''Camelus bactrianus ferus'') is still debated.] The divergence date is 0.7 million years ago, long before the start of domestication.
Scientific classification
Family Camelidae
* †Subfamily Poebrotheriinae
* †Subfamily Miolabinae
* †Subfamily Stenomylinae
Camelids are members of the biological family Camelidae, the only currently living family in the suborder Tylopoda. The seven extant members of this group are: dromedary camels, Bactrian camels, wild Bactrian camels, llamas, alpacas, vicuñas ...
* †Subfamily Floridatragulinae
* Subfamily Camelinae
Camelinae is a subfamily of Even-toed ungulate, artiodactyls of the family (biology), family Camelidae, known from Asia, Eurasia, South America, North America, and Africa appearing during the Eocene 38 Annum, mya, existing for approximately .
Ca ...
** Tribe Lamini
Lamini (members are called ''laminoids'') is a tribe of the subfamily Camelinae. It contains one extant genus with four species, all exclusively from South America: llamas, alpacas, vicuñas, and guanacos. The former two are domesticated spec ...
*** Genus: ''Lama
Lama (; "chief") is a title for a teacher of the Dharma in Tibetan Buddhism. The name is similar to the Sanskrit term ''guru'', meaning "heavy one", endowed with qualities the student will eventually embody. The Tibetan word "lama" means "hig ...
''
**** Llama
The llama (; ) (''Lama glama'') is a domesticated South American camelid, widely used as a meat and pack animal by Andean cultures since the Pre-Columbian era.
Llamas are social animals and live with others as a herd. Their wool is soft ...
, ''Lama glama''
**** Guanaco, ''Lama guanicoe''
**** Alpaca
The alpaca (''Lama pacos'') is a species of South American camelid mammal. It is similar to, and often confused with, the llama. However, alpacas are often noticeably smaller than llamas. The two animals are closely related and can success ...
, ''Lama pacos''
**** Vicuña, ''Lama vicugna''
*** Genus: ''Hemiauchenia
''Hemiauchenia'' is a genus of laminoid camelids that evolved in North America in the Miocene period about 10 million years ago. This genus diversified and moved to South America in the Early Pleistocene, as part of the Great American Biotic I ...
''
**** †'' Hemiauchenia macrocephala''
**** †'' Hemiauchenia minima''
**** †'' Hemiauchenia blancoensis''
**** †'' Hemiauchenia vera''
**** †'' Hemiauchenia paradoxa''
*** Genus ''Palaeolama
''Palaeolama'' () is an extinct genus of laminoid camelid that existed from the Late Pliocene to the Early Holocene (). Their range extended from North America to the intertropical region of South America.
Description
''Palaeolama'' were rel ...
''
**** †''Palaeolama mirifica
''Palaeolama'' () is an extinct genus of laminoid camelid that existed from the Late Pliocene to the Early Holocene (). Their range extended from North America to the intertropical region of South America.
Description
''Palaeolama'' were rela ...
''
** Tribe Camelini
*** Genus: ''Camel
A camel (from: la, camelus and grc-gre, κάμηλος (''kamēlos'') from Hebrew or Phoenician: גָמָל ''gāmāl''.) is an even-toed ungulate in the genus ''Camelus'' that bears distinctive fatty deposits known as "humps" on its back. ...
us''
**** Bactrian camel
The Bactrian camel (''Camelus bactrianus''), also known as the Mongolian camel or domestic Bactrian camel, is a large even-toed ungulate native to the steppes of Central Asia. It has two humps on its back, in contrast to the single-humped dro ...
, ''Camelus bactrianus''
**** Dromedary
The dromedary (''Camelus dromedarius'' or ;), also known as the dromedary camel, Arabian camel, or one-humped camel, is a large even-toed ungulate, of the genus '' Camelus'', with one hump on its back.
It is the tallest of the three species o ...
, ''Camelus dromedarius''
**** Wild Bactrian camel
The wild Bactrian camel (''Camelus ferus'') is a critically endangered species of camel living in parts of northwestern China and southwestern Mongolia. It is closely related to the Bactrian camel (''Camelus bactrianus''). Both are large, doubl ...
, ''Camelus ferus''
**** † Syrian camel, '' Camelus moreli''
**** †'' Camelus sivalensis''
***Genus: '' Camelops''
**** †''Camelops hesternus
''Camelops''Being occasionally called ''Western Camel'' or ''Yesterday's Camel''. is an extinct genus of camels that lived in North and Central America, ranging from Alaska to Guatemala, from the middle Pliocene to the end of the Pleistocene. It ...
''
***Genus: '' Paracamelus''
**** †'' Paracamelus gigas''
Phylogeny
Extinct genera
References
External links
Pictures of camelid species
{{Authority control
Extant Lutetian first appearances
Mammal families
Taxa named by John Edward Gray
Tylopoda