Editing Reindeer (section)

=== Diet ===
[[File:Reindeer licking salt from roadway.jpg|thumb|Two caribou licking salt from a roadway in [[British Columbia]]]]

Reindeer are [[ruminant]]s, having a four-chambered stomach. They mainly eat [[lichen]]s in winter, especially reindeer lichen (''[[Cladonia rangiferina]]''); they are the only large mammal able to metabolize lichen owing to specialised bacteria and protozoa in their gut.<ref name="McCloskey2011">{{citation|title=Wolves in Canada|last=McCloskey|first=Erin| publisher=Lone Pines |year=2011 |chapter=Caribou |pages=72–82 |isbn=978-1-55105-872-6}}</ref> They are also the only animals (except for some [[Gastropoda|gastropods]]) in which the enzyme [[lichenase]], which breaks down [[lichenin]] to [[glucose]], has been found.<ref>{{cite book |author=Lawrence, Eleanor |title=Henderson's Dictionary of Biology |url=https://books.google.com/books?id=ymGPfl_HDv8C&pg=PA363 |year=2008 |publisher=Pearson Benjamin Cummings Prentice Hall |isbn=978-0-321-50579-8 |pages=363–|url-status=live |archive-url=https://web.archive.org/web/20160510185334/https://books.google.com/books?id=ymGPfl_HDv8C&pg=PA363 |archive-date=10 May 2016 }}</ref> However, they also eat the leaves of [[willow]]s and [[birch]]es, as well as [[Cyperaceae|sedge]]s and [[Poaceae|grasses]].

Reindeer are [[Osteophagy|osteophagous]]; they are known to gnaw and partly consume shed antlers as a dietary supplement and in some extreme cases will cannibalise each other's antlers before shedding.<ref>{{cite web |last1=Pomeroy |first1=Ross |title=Curious Case of Reindeer Cannibalism May Have Led to Deadly Prion Disease |url=https://www.realclearscience.com/articles/2020/12/21/why_did_reindeer_in_norway_eat_each_others_antlers_653829.html |website=Real Clear Science |date=21 December 2020 |publisher=RealClearScience.com |access-date=30 June 2021}}</ref> There is also some evidence to suggest that on occasion, especially in the spring when they are nutritionally stressed,<ref>[http://www.villrein.no/Factsaboutwildreindeer/Biology/tabid/7041/Default.aspx Biology] {{webarchive|url=https://web.archive.org/web/20131029202301/http://www.villrein.no/Factsaboutwildreindeer/Biology/tabid/7041/Default.aspx |date=29 October 2013 }}. Villrein.no. Retrieved on 19 April 2014.</ref> they will feed on small rodents (such as [[lemming]]s),<ref>[https://web.archive.org/web/20111107145338/http://www.hww.ca/hww2.asp?id=91 Lemmings] at [[Hinterland Who's Who]]</ref> fish (such as the [[Arctic char]] (''Salvelinus alpinus'')), and [[Egg|bird egg]]s.<ref>Anand-Wheeler, Ingrid (2002) ''Terrestrial Mammals of Nunavut''. Nunavut Wildlife Management Board. {{ISBN|1-55325-035-4}}.</ref> Reindeer herded by the [[Chukchi people|Chukchis]] have been known to devour mushrooms enthusiastically in late summer.<ref>[http://www.folklore.ee/folklore/vol32/siimets.pdf "The Sun, the Moon and Firmament in Chukchi Mythology and on the Relations of Celestial Bodies and Sacrifice" by Ülo Siimets at 140] {{webarchive|url=https://web.archive.org/web/20080911091443/http://www.folklore.ee/folklore/vol32/siimets.pdf |date=11 September 2008 }}. (PDF) . Retrieved on 16 September 2011.</ref>

During the Arctic summer, when there is [[Midnight sun|continuous daylight]], reindeer change their sleeping pattern from one [[Circadian rhythm|synchronised with the sun]] to an [[Ultradian rhythm|ultradian]] pattern, in which they sleep when they need to digest food.<ref name = "Hickok2018">{{cite web | url= https://www.livescience.com/62870-summer-solstice-animals.html | title=How Does the Summer Solstice Affect Animals? | last= Hickok | first= K. | date= 21 June 2018 | website= [[Live Science]] | access-date= 22 June 2018}}</ref>

[[Δ13C|''δ''<sup>13</sup>C<sub>C</sub>]] values indicate reindeer living in the region around [[Biśnik Cave]] exhibited minimal ecological change during the transition from [[Marine isotope stages|MIS 3]] to MIS 2.<ref>{{Cite journal |last1=Piskorska |first1=Teresa |last2=Stefaniak |first2=Krzysztof |last3=Krajcarz |first3=Magdalena |last4=Krajcarz |first4=Maciej T. |date=2 March 2015 |title=Reindeer during the Upper Palaeolithic in Poland: Aspects of variability and paleoecology |url=https://www.sciencedirect.com/science/article/abs/pii/S1040618214005837 |journal=[[Quaternary International]] |language=en |volume=359-360 |pages=157–177 |doi=10.1016/j.quaint.2014.08.027 |bibcode=2015QuInt.359..157P |access-date=7 September 2024 |via=Elsevier Science Direct}}</ref> Dental [[mesowear]] indicates that during the Late Pleistocene, reindeer living in central Alaska had highly abrasive diets similar to wild horses.<ref>{{Cite journal |last1=Rivals |first1=Florent |last2=Mihlbachler |first2=Matthew C. |last3=Solounias |first3=Nikos |last4=Mol |first4=Dick |last5=Semprebon |first5=Gina M. |last6=de Vos |first6=John |last7=Kalthoff |first7=Daniela C. |date=1 February 2010 |title=Palaeoecology of the Mammoth Steppe fauna from the late Pleistocene of the North Sea and Alaska: Separating species preferences from geographic influence in paleoecological dental wear analysis |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018209005318 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |language=en |volume=286 |issue=1–2 |pages=42–54 |doi=10.1016/j.palaeo.2009.12.002 |bibcode=2010PPP...286...42R |access-date=7 September 2024 |via=Elsevier Science Direct}}</ref>
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