Editing Camelidae (section)

==Characteristics==
[[File:Camel Foot.jpg|thumb|Camelid feet lack functional hooves, with the toe bones being embedded in a broad, cutaneous pad.<ref name="Domestic" />]]

Camelids are large, strictly [[herbivorous]] animals with slender necks and long legs. They differ from [[ruminant]]s in a number of ways.<ref name="Fowler, M.E. 2010">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.</ref> Their dentition show traces of vestigial central [[incisor]]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. As in ruminants, the upper incisors are largely absent and are replaced by a [[dental pad]] consisting of connective tissue covered with [[epithelium]].<ref>{{Citation |last=Niehaus |first=Andrew |title=Tooth Root Abscess |date=2022 |url=https://linkinghub.elsevier.com/retrieve/pii/B9780323910156000893 |work=Comparative Veterinary Anatomy |pages=1013–1019 |access-date=2023-10-29 |publisher=Elsevier |language=en |doi=10.1016/b978-0-323-91015-6.00089-3 |isbn=978-0-323-91015-6|url-access=subscription }}</ref> 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.<ref name="Domestic">{{cite book | author = Clutton-Brock, Juliet| title = A Natural History of Domesticated Mammals | year = 1987 | pages = 208 | publisher = Cambridge University Press | isbn = 978-0-521-34697-9}}</ref> They have three-chambered [[stomach]]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]]s are elliptical.<ref name="Fowler, M.E. 2010"/> They also have a unique type of [[antibody|antibodies]], which lack the light chain, in addition to the normal antibodies found in other mammals. These so-called [[heavy-chain antibodies]] are being used to develop [[single-domain antibodies]] with potential [[pharmaceutical]] applications.

Camelids do not have hooves; rather, they have two-toed feet with toenails and soft foot pads ([[Tylopoda]] 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.<ref name=EoM>{{cite book|editor= Macdonald, D.|author= Franklin, William|year= 1984|title= The Encyclopedia of Mammals|publisher= Facts on File|location= New York|pages= [https://archive.org/details/encyclopediaofma00mals_0/page/512 512–515]|isbn= 978-0-87196-871-5|url-access= registration|url= https://archive.org/details/encyclopediaofma00mals_0/page/512}}</ref> 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, which helps to distribute weight across the foot.<ref>{{Cite journal|last1=Clemente|first1=Christofer J.|last2=Dick|first2=Taylor J. M.|last3=Glen|first3=Christopher L.|last4=Panagiotopoulou|first4=Olga|date=2020-03-02|title=Biomechanical insights into the role of foot pads during locomotion in camelid species|url= |journal=Scientific Reports|language=en|volume=10|issue=1|pages=3856|doi=10.1038/s41598-020-60795-9|issn=2045-2322|pmc=7051995|pmid=32123239|bibcode=2020NatSR..10.3856C}}</ref> Many fossil camelids were [[unguligrade]] and probably hooved, in contrast to all living species.<ref name=MamEv>{{cite book|author1= Savage, RJG|author2= Long, MR|year= 1986|title= Mammal Evolution: an illustrated guide|publisher= Facts on File|location= New York|pages= [https://archive.org/details/mammalevolutioni0000sava/page/216 216–221]|isbn= 978-0-8160-1194-0|url= https://archive.org/details/mammalevolutioni0000sava/page/216}}</ref>

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, which ensures that the fore and hind limb will not collide while in fast motion. During this motion, all four limbs momentarily are off the ground at the same time.<ref>{{Cite journal|last1=Janis|first1=Christine M.|last2=Theodor|first2=Jessica M.|last3=Boisvert|first3=Bethany|date=2002-03-14|title=Locomotor evolution in camels revisited: a quantitative analysis of pedal anatomy and the acquisition of the pacing gait|url=http://www.tandfonline.com/doi/abs/10.1671/0272-4634%282002%29022%5B0110%3ALEICRA%5D2.0.CO%3B2|journal=Journal of Vertebrate Paleontology|language=en|volume=22|issue=1|pages=110–121|doi=10.1671/0272-4634(2002)022[0110:LEICRA]2.0.CO;2|s2cid=86174860 |issn=0272-4634|url-access=subscription}}</ref> Consequently, camelids large enough for human beings to ride have a typical swaying motion.

Dromedary camels, bactrian camels, llamas, and alpacas are all [[Induced ovulation (animals)|induced ovulators]].<ref name="Chen">{{cite journal|journal=J. Reprod. Fertil.|year=1985|volume=74|issue=2|pages=335–339|title=Semen-induced ovulation in the bactrian camel (Camelus bactrianus).|author=Chen, B.X.|author2=Yuen, Z.X.|author3=Pan, G.W.|name-list-style=amp|access-date=September 12, 2014|url=http://www.reproduction-online.org/content/74/2/335.full.pdf|doi=10.1530/jrf.0.0740335|pmid=3900379|doi-access=free}}</ref>

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]], and some herds live in nuclear test areas.<ref>[https://web.archive.org/web/20021206012648/http://news.nationalgeographic.com/news/2002/11/1126_021205_cameltrek.html Wild Bactrian Camels Critically Endangered, Group Says] National Geographic, 3 December 2002</ref>

Comparative table of the seven extant species in the family Camelidae:
{| class="wikitable" style="text-align:center;"
|-
! Species
! Image
! Natural range
! Weight
|-
|colspan="10" align=center style="background-color:BurlyWood" |'''''[[Camel]]us'''''
|-
| [[Bactrian camel]]
(''Camelus bactrianus'')
| align="center" | [[File:2011 Trampeltier 1528.JPG|x75px]]
|[[Central Asia|Central]] and [[Inner Asia]]<br />(entirely domesticated)
| {{convert|300|to|1000|kg|lbs|abbr=on}}
|-
| [[Dromedary]]<br />or<br />Arabian camel
(''Camelus dromedarius'')
| [[File:07. Camel Profile, near Silverton, NSW, 07.07.2007.jpg|x75px]]
| South Asia and Middle East<br />(entirely domesticated)
| {{convert|300|to|600|kg|lbs|abbr=on}}
|-
| [[Wild Bactrian camel]]
(''Camelus ferus'')
| [[File:Wild Bactrian camel on road east of Yarkand.jpg|100px]]
| China and Mongolia
| 300 to 820&nbsp;kg (660 to 1,800&nbsp;lb)
|-
|colspan="10" align=center style="background-color:BurlyWood" |'''''[[Lama (genus)|Lama]]'''''
|-
| [[Llama]]
(''Lama glama'')
| [[File:Domestic llama (2009-05-19).jpg|x75px]]
| (domestic form of guanaco)
| {{convert|130|to|200|kg|lbs|abbr=on}}
|-
| [[Guanaco]]
(''Lama guanicoe'')
| [[File:Guanaco 09.24.jpg|x75px]]
| South America
| about {{convert|90|to|120|kg|lbs|abbr=on}}
|-
| [[Alpaca]]
(''Lama pacos'')
| [[File:Alpaca (31562329701).jpg|x75px]]
| (domestic form of vicuña)
| {{convert|48|to|84|kg|lbs|abbr=on}}
|-
| [[Vicuña]]
(''Lama vicugna'')
| [[File:Vicunacrop.jpg|x75px]]
| South American [[Andes]]
| {{convert|35|to|65|kg|lbs|abbr=on}}
|}