Editing Arctic hare (section)

== Physiology ==
The Arctic hare has many physiological features that are adaptive to its extreme environment. Despite a 17% - 38% lower than expected [[basal metabolic rate]], the Arctic hare is able to maintain a body temperature comparable to other lagomorphs (38.9 degrees C) because of its low surface area to volume ratio and high insulation.<ref name=":0">{{Cite journal|last1=Wang|first1=Lawrence C. H.|last2=Jones|first2=Douglas L.|last3=MacArthur|first3=Robert A.|last4=Fuller|first4=William A.|date=2011-02-14|title=Adaptation to cold: energy metabolism in an atypical lagomorph, the arctic hare (Lepus arcticus)|url=https://cdnsciencepub.com/doi/abs/10.1139/z73-125|journal=Canadian Journal of Zoology|volume=51|issue=8|pages=841–846|language=en|doi=10.1139/z73-125|pmid=4750284|url-access=subscription}}</ref><ref name=":13"/><ref name=":2">{{Cite journal|last=Hacklaender|first=Klaus|date=2018|title=Lepus arcticus Ross, 1819, Arctic hare|journal=Lagomorphs|pages=165–168}}</ref> The lowered metabolic rate also allows the Arctic hare to save energy, making it adaptive for its cold and barren habitat.<ref name=":0" /><ref name=":13"/><ref name=":2" /> In addition, the Arctic hare has high locomotive efficiency combined with long periods of resting and shorter bouts of foraging which enables it to conserve energy and survive on its low diet intake.<ref name=":3">{{Cite journal|last=Klein|first=David R.|date=1999|title=Comparative social learning among Arctic herbivores: the caribou, muskox, and Arctic hare.|journal=Symposia of the Zoological Society of London|volume=72|pages=126–140}}</ref>

[[File:Petjada-llebre-artica.jpg|thumb|right|Arctic hare footprints on the snow]]
The white fur of Arctic hares, in addition to their camouflage benefits in the winter, have a high [[reflectance]] which may prevent excessive heat gain during the day.<ref name=":13"/><ref name=":2" /> Behaviorally, the Arctic hare keeps warm in winter using body orientation, posture, and seeking or digging shelter.<ref name=":4">{{Cite journal|last=Gray|first=David R.|date=1993|title=Behavioural Adaptations to Arctic Winter: Shelter Seeking by Arctic Hare (Lepus Arcticus)|journal=Arctic|volume=46|issue=4|pages=340–353|doi=10.14430/arctic1362|jstor=40511436|issn=0004-0843|doi-access=free}}</ref> When resting, Arctic hares maintain a nearly spherical shape and typically stay in groups, but do not huddle.<ref name=":4" /> If the rabbits are solitary, they often rest in the shelter of large rocks protecting them from the wind and staying out of sight of predators.<ref name=":4" /><ref name=":13"/><ref name=":3" /><ref name=":2" /> In addition to rocks, Arctic hares also find shelter in other natural shelters such as snowdrifts, man-made structures, and even digging their own burrows in snowdrifts up to 188&nbsp;cm in length.<ref name=":4" />

The body size of Arctic hares is often significantly less in the winter compared to the summer, likely caused by decreased food quality and availability in addition to a decreased metabolic rate.<ref name=":13"/><ref name=":2" /> Arctic hare body mass might also be affected by ambient temperature. At lower latitudes it was found that Arctic hares in [[Greenland]] exhibited larger body size with increased temperature, possibly caused by increased energy availability to contribute to body size and increased food plant availability.<ref name=":5">{{Cite journal|last1=Yom-Tov|first1=Elad|last2=Yom-Tov|first2=Yoram|last3=Yom-Tov|first3=Shlomith|last4=Andersen|first4=Mogens|last5=Rosenfeld|first5=Daniel|last6=Devasthale|first6=Abhay|last7=Geffen|first7=Eli|date=2017-04-01|title=The complex effects of geography, ambient temperature, and North Atlantic Oscillation on the body size of Arctic hares in Greenland|journal=Biological Journal of the Linnean Society|volume=120|issue=4|pages=909–918|doi=10.1093/biolinnean/blw018|issn=0024-4066|doi-access=free}}</ref> The opposite is true at higher latitudes in which Arctic hares had smaller body sizes with increased temperature.<ref name=":5" /> This trend is again linked to food plant availability.<ref name=":5" /> In this case, decreased precipitation and increased temperatures in the higher latitudes of Greenland result in a lower food plant availability to contribute to body mass.<ref name=":5" />