User:Lithopslover/Arctic Hare

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. The lowered metabolic rate also allows the Arctic hare to save energy, making it adaptive for its cold and barren habitat. 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.

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. Behaviorally, the Arctic hare keeps warm in winter using body orientation, posture, and seeking or digging shelter. When resting, Arctic hares maintain a nearly spherical shape and typically stay in groups, but do not huddle. 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. 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 188cm in length.

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. 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. The opposite is true at higher latitudes in which Arctic hares had smaller body sizes with increased temperature. This trend is again linked to food plant availability. 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.

Feeding[edit]
The Arctic hare is a herbivore, specifically a folivore. Arctic hares feed primarily on woody plants, with arctic willow constituting 95% of their diet year-round. Arctic hares predominantly consume saxifrage, crowberry, and dwarf willow, but can also eat a variety of other foods, including lichens and mosses, blooms, other species' leaves, twigs, and roots, mountain sorrel and macroalgae (seaweed). Arctic hare diets are more diverse in summer. Although previously believed to still be primarily willow, dryas, and grasses, recent studies show that their diet becomes dominated by legumes, constituting 70% of their diet in the summer. Arctic hares have been reported to occasionally eat meat, including fish and the stomach contents of eviscerated caribou. They eat snow to get water.

Reproduction and lifespan[edit]
Breeding season occurs around April or May. Gestation period of the Arctic hare is 53 days, so the babies are born around May, June, or July. Hares can have up to eight babies (average litter size 5.4), called leverets. The leverets stay within the mother's home range until they can survive on their own. Young Arctic hares are almost full size by late July (some weeks after birth) and breed for the first time after a year of age.

There is little information on the lifespan of Arctic hares. Some anecdotal evidence suggests they live three to five years in the wild. Arctic hares do not fare well in captivity, living only a year and a half at most.