Editing Reindeer (section)

=== Pelt ===
The color of the [[fur]] varies considerably, both between individuals and depending on season and species. Northern populations, which usually are relatively small, are whiter, while southern populations, which typically are relatively large, are darker. This can be seen well in North America, where the northernmost subspecies, the [[Peary caribou]], is the whitest and smallest subspecies of the continent, while the Selkirk Mountains caribou (Southern Mountain population DU9)<ref name="Allen-1902" /> is the darkest and nearly the largest,<ref name=NorthAmerica>Reid, F. (2006). ''Mammals of North America''. Peterson Field Guides. {{ISBN|978-0-395-93596-5}}</ref> only exceeded in size by Osborn's caribou (Northern Mountain population DU7).<ref name="Allen-1902" />

The [[Animal coat|coat]] has two layers of fur: a dense [[wool]]ly undercoat and a longer-haired overcoat consisting of hollow, air-filled hairs.<ref name="Bennett116">{{citation|last=Bennett |first=John|publisher=McGill-Queen's University Press|series=McGill-Queen's Native and Northern Series |date=1 June 2008|title=Uqalurait: An Oral History of Nunavut|page=116}}</ref>{{efn|According to Inuit elder Marie Kilunik of the [[Aivilingmiut]], Canadian Inuit preferred the caribou skins from caribou taken in the late summer or autumn, when their coats had thickened. They used it for winter clothing "because each hair is hollow and fills with air trapping heat."<ref>Marie Kilunik, Aivilingmiut, & Crnkovich, 1990, p. 116{{full citation needed|date=November 2022}}</ref> Fur is the primary insulation factor that allows reindeer to regulate their [[Human body temperature#Core temperature|core body temperature]] in relation to their environment, the [[Temperature gradient|thermogradient]], even if the temperature rises to {{cvt|100|F|order=flip}}.<ref name="Moote1955">{{cite journal |last=Moote |first=I. |year=1955 |title=The thermal insulation of caribou pelts |journal=Textile Research Journal |volume=25 |number =10 |pages=832–837 |doi=10.1177/004051755502501002 |s2cid=138926309}}</ref> In 1913, Dugmore noted how the woodland caribou swim so high out of the water, unlike any other mammal, because their hollow, "air-filled, quill-like hair" acts as a supporting "life jacket".<ref name="Dugmore1913">{{citation |first=Arthur Radclyffe |last=Dugmore |title=The romance of the Newfoundland caribou|page=191 |year=1913 |access-date=2 November 2014 |location=Philadelphia |publisher=Lippincott |url=https://archive.org/stream/romanceofnewfoun00dugm/romanceofnewfoun00dugm_djvu.txt}}</ref>

A darker belly color may be caused by two mutations of [[Melanocortin 1 receptor|MC1R]]. They appear to be more common in domestic reindeer herds.<ref name=Vage2014>{{cite journal |title=Two Missense Mutations in Melanocortin 1 Receptor (MC1R) Are Strongly Associated With Dark Ventral Coat Color in Reindeer (''Rangifer Tarandus'') |year=2014 |doi=10.1111/age.12187 |hdl=2164/4960| hdl-access=free| last1=Våge |first1=D. I. |last2=Nieminen |first2=M. |last3=Anderson |first3=D. G. |last4=Røed |first4=K. H. |journal=Animal Genetics |volume=45 |issue=5 |pages=750–753 |pmid=25039753}}</ref>