Historical records of animals caught by fur hunters over hundreds of years show the lynx and hare numbers rising and falling in a cycle, which has made the hare known to biology students worldwide as a case study of the relationship between numbers of predators and their prey.

[7] Populations in its southern range, such as in Ohio, Maryland, North Carolina, New Jersey, Tennessee, and Virginia have been extirpated.

[8] Locations of subspecies are as follows:[9] The snowshoe hare's fur is rusty brown in the spring and summer, and white in the winter.

In the summer, the coat is a grizzled rusty or grayish brown, with a blackish middorsal line, buffy flanks and a white belly.

[12] In the Southwest, the southernmost populations of snowshoe hares occur in the Sangre de Cristo Mountains, New Mexico, in subalpine scrub: narrow bands of shrubby and prostrate conifers at and just below timberline that are usually composed of Engelmann spruce, bristlecone pine, limber pine, and juniper.

They are shy and secretive and spend most of the day in shallow depressions, called forms, scraped out under clumps of ferns, brush thickets, and downed piles of timber.

[15][16] In northwestern Oregon, male peak breeding activity (as determined by testes weight) occurs in May and is at the minimum in November.

Female estrus begins in March in Newfoundland, Alberta, and Maine, and in early April in Michigan and Colorado.

[7][15] Deep snow-pack increases the amount of upper-branch browse available to snowshoe hares in winter, and therefore has a positive relationship with the nutritional status of breeding adults.

The period of abundance usually lasts for two to five years, followed by a population decline to lower numbers or local scarcity.

[21] Exclosure experiments in Alberta indicated browsing by snowshoe hares during population peaks has the greatest impact on palatable species, thus further reducing the amount of available foods.

In this study, insufficient nutritious young browse was available to sustain the number of snowshoe hares present in the peak years (1971 and 1972) in winter.

The presence of cover is the primary determinant of habitat quality, and is more significant than food availability or species composition.

In New England, snowshoe hares preferred second-growth deciduous, coniferous, and mixed woods with dense brushy understories; they appear to prefer shrubby old-field areas, early- to mid-successional burns, shrub-swamps, bogs, and upper montane krumholz vegetation.

In British Columbia overstocked juvenile lodgepole pine (Pinus contorta) stands formed optimal snowshoe hare habitat.

[28] In western Washington, most unburned, burned, or scarified clearcuts will normally be fully occupied by snowshoe hares within four to five years, as vegetation becomes dense.

[29] In older stands (more than 25 years), stem density begins to decline and cover for snowshoe hares decreases.

[21] In western Oregon, snowshoe hares were abundant only in early successional stages, including stable brushfields.

A few snowshoe hares were noted in adjacent virgin forest plots; they represented widely scattered, sparse populations.

One snowshoe hare was observed on the disturbed plot 2.5 years after it had been clearcut and burned; at this stage, ground cover was similar to that of the uncut forest.

On the Island of Montreal in Quebec, the average daily range for both sexes was 4 acres (1.6 ha) in old-field mixed woods.

[20] The snowshoe hare winter diet is dominated by bog birch (Betula glandulosa), which is preferred but not always available.

[37] In northwestern Oregon, winter foods include needles and tender bark of Sitka spruce, Douglas-fir, and western hemlock (Tsuga heterophylla); leaves and green twigs of salal; buds, twigs, and bark of willows; and green herbs.

[15] In north-central Washington, willows and birches are not plentiful; snowshoe hares browse the tips of lodgepole pine seedlings.

[39] In New Brunswick, snowshoe hares consumed northern white-cedar, spruces, American beech (Fagus grandifolia), balsam fir, mountain maple (A. spicatum), and many other species of browse.

In summer, leaves of willows, black spruce, birches, and bog Labrador tea (Ledum groenlandicum) are also consumed.

), other forbs, and some woody plants, including Sitka spruce, Douglas-fir, and young leaves and twigs of salal.

Its foremost predator is the Canada lynx (Lynx canadensis), but other predators include bobcats (L. rufus), fishers (Pekania pennanti), American martens (Martes americana), Pacific martens, (M. caurina), long-tailed weasels (Neogale frenata), minks (N. vison), foxes (Vulpes and Urocyon spp.

[7] In Glacier National Park snowshoe hares are a prey item of Rocky Mountain wolves (Canis lupus irremotus).

that snowshoe hare populations are at risk of crashing unless interbreeding speeds up the process of evolution to year-round brown.