Snowshoe hare

The snowshoe hare was first described in 1777 by the German naturalist Johann Christian Polycarp Erxleben. He called it the American hare, and placed it in the genus Lepus, noting that it was intermediate in size between the European rabbit (Oryctolagus cuniculus) and the mountain hare (Lepus timidus) but had longer hindfeet than the latter species. The following subspecies are known: • Lepus americanus americanus (Erxleben) – Ontario, Manitoba, Saskatchewan, Alberta, Montana, and North Dakota • L. a. cascadensis (Nelson) – British Columbia and Washington • L. a. columbiensis (Rhoads) – British Columbia, Alberta, and Washington • L. a. dalli (Merriam) – Mackenzie District, British Columbia, Alaska, Yukon • L. a. klamathensis (Merriam) – Oregon and California • L. a. oregonus (Orr) – Oregon • L. a. pallidus (Cowan) – British Columbia • L. a. phaeonotus (J. A. Allen) – Ontario, Manitoba, Saskatchewan, Michigan, Wisconsin, and Minnesota • L. a. pineus (Dalquest) – British Columbia, Idaho, and Washington • L. a. seclusus (Baker and Hankins) – Wyoming • L. a. struthopus (Bangs) – Newfoundland, Nova Scotia, New Brunswick, Prince Edward Island, Quebec, and Maine • L. a. tahoensis (Orr) – California, western Nevada • L. a. virginianus (Harlan) – Ontario, Quebec, Maine, New Hampshire, Vermont, Massachusetts, New York, Pennsylvania • L. a. washingtonii (Baird) – British Columbia, Washington, and Oregon ==Description==

The snowshoe hare's fur is rusty brown in the spring and summer, and white in the winter. It also always has a gray underbelly, and black on the tips and edges of its ears and tail. It has very large hind feet, and dense fur on their soles. The snowshoe hare's ears are not as long as some other species of hares' ears. In the winter, it turns a bright white to blend in with the snow. Snowshoe hares range in length from 413 to 518 mm (16.3 to 20.4 in), of which 39 to 52 mm (1.5 to 2.0 in) are tail. The hind foot, long and broad, measures 117 to 147 mm (4.6 to 5.8 in) in length. The ears are 62 to 70 mm (2.4 to 2.8 in) from notch to tip. Snowshoe hares usually weigh between 1.43 and 1.55 kg (3.15 to 3.42 lb). Males are slightly smaller than females, as is typical for leporids. In the summer, the coat is a grizzled rusty or grayish brown, with a blackish middorsal line, buffy flanks and a white belly. The face and legs are cinnamon brown. The ears are brownish with black tips and white or creamy borders. During the winter, the fur is almost entirely white, except for black eyelids and the blackened tips on the ears. The soles of the feet are densely furred, with stiff hairs (forming the snowshoe) on the hind feet. == Distribution and habitat ==

Distribution Snowshoe hares occur from Newfoundland to Alaska; south in the Sierra Nevada to central California; in the Rocky Mountains to southern Utah and northern New Mexico; and in the Appalachian Mountains to West Virginia. Populations in its southern range, such as in Ohio, Maryland, North Carolina, New Jersey, Tennessee, and Virginia have been extirpated. Fossil record During the Late Pleistocene, the snowshoe hare was found south of its current range in the area around Herculaneum, Missouri. Habitat Snowshoe hares are primarily found in areas with dense plant coverage such as boreal forests, upper montane forests and wetlands, though are occasionally seen in more open areas like agricultural land. In Utah, snowshoe hares used Gambel oak (Quercus gambelli) in the northern portion of the Gambel oak range. 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. In Minnesota, snowshoe hares are found in uplands and wetlands. In New England, snowshoe hares favor second-growth forests. Major variables in habitat quality include average visual obstruction and browse biomass. Snowshoe hares prefer young forests with abundant understories. The presence of cover is the primary determinant of habitat quality, and is more significant than food availability or species composition. Species composition does, however, influence population density; dense softwood understories support greater snowshoe hare density than hardwoods because of cover quality. In Maine, female snowshoe hares were observed to be more common on sites with less cover but more nutritious forage; males tended to be found on sites with heavier cover. Winter browse availability depends on height of understory brush and winter snow depth; saplings with narrow stem diameters are required for winter browse in heavy snow. In northern regions, snowshoe hares occupy conifer and mixed forests in all stages of succession, but early successional forests foster peak abundance. Deciduous forests are usually occupied only in early stages of succession. 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 Maine, snowshoe hares were more active in clearcut areas than in partially cut or uncut areas. Sapling densities were highest on 12- to 15-year-old plots; these plots were used more than younger stands. In northern Utah, they occupied all the later stages of succession on quaking aspen and spruce-fir, but were not observed in meadows. In Alberta, snowshoe hares use upland shrub-sapling stages of regenerating aspens (either postfire or postharvest). In British Columbia overstocked juvenile lodgepole pine (Pinus contorta) stands formed optimal snowshoe hare habitat. 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. In older stands (more than 25 years), stem density begins to decline and cover for snowshoe hares decreases. However, in north-central Washington, they may not colonize clearcuts until six or seven years, and it may take 20 to 25 years for their density to reach maximum. Winter snowshoe hare pellet counts were highest in 20-year-old lodgepole pine stands, lower in older lodgepole stands, and lowest in spruce-dominated stands. In west-central Oregon, an old-growth Douglas-fir forest was clearcut and monitored through 10 years of succession. 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. By 9 years after disturbance, snowshoe hare density had increased markedly. In western Washington, snowshoe hares routinely used steep slopes where cover was adequate; most studies, however, suggest they tend to prefer gentle slopes. Their activity usually shifts from coniferous understories in winter to hardwood understories in summer. Vegetative structure plays an important role in the size of snowshoe hare home ranges. Snowshoe hares wander up to 5 miles (8 km) when food is scarce. In Montana home ranges are smaller in brushy woods than in open woods. In Colorado and Utah, the average home range of both sexes was 20 acres (8.1 ha). 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. In Montana, the home range averaged 25 acres (10 ha) for males and 19 acres (7.6 ha) for females. In Oregon the average snowshoe hare home range was 14.6 acres (5.9 ha). Cover requirements Snowshoe hares require dense, brushy, usually coniferous cover; thermal and escape cover are especially important for young hares. Low brush provides hiding, escape, and thermal cover. Heavy cover 10 feet (3 m) above ground provides protection from avian predators, and heavy cover 3.3 feet (1 m) tall provides cover from terrestrial predators. Overwinter survival increases with increased cover. A wide variety of habitat types are used if cover is available. Base visibility in good snowshoe hare habitat ranges from 2% at 16.5 feet (5 m) distance to 0% at 66 feet (20 m). Travel cover is slightly more open, ranging from 14.7% visibility at 16.5 feet (5 m) to 2.6% at 66 feet (20 m). Areas with horizontal vegetation density of 40 to 100% at 50 feet (15 m) are adequate snowshoe hare habitat in Utah. == Behavior and ecology ==

Snowshoe hares are crepuscular and nocturnal. 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. They occasionally use the large burrows of mountain beavers (Aplodontia rufa) as forms. Diurnal activity level increases during the breeding season. Juveniles are usually more active and less cautious than adults. Reproduction Snowshoe hares are active year-round. The breeding season for hares is stimulated by new vegetation and varies with latitude, location, and yearly events (such as weather conditions and phase of snowshoe hare population cycle). 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. Litters are usually smaller in the southern sections of their range since there is less snow. Newborns are fully furred, open-eyed, and mobile. They leave the natal form within a short time after birth, often within 24 hours. After leaving the birthplace, siblings stay near each other during the day, gathering once each evening to nurse. Female snowshoe hares can become pregnant anytime after the 35th day of gestation. The second litter can therefore be conceived before the first litter is born (snowshoe hares have twin uteri). Diet Snowshoe hares eat a variety of plant materials. Forage type varies with season. Succulent green vegetation is consumed when available from spring to fall; after the first frost, buds, twigs, evergreen needles, and bark form the bulk of snowshoe hare diets until spring greenup. Winter . Snowshoe hares prefer branches, twigs, and small stems up to 0.25 inch (6.3 mm) diameter; larger stems are sometimes used in winter. The snowshoe hare winter diet is dominated by bog birch (Betula glandulosa), which is preferred but not always available. Greyleaf willow (Salix glauca) is eaten most often when bog birch is not available. Buffaloberry (Shepherdia canadensis) is the fourth most common diet item. White spruce (Picea glauca) is eaten, but not preferred. In Alaska, spruce, willows, and alders comprise 75% of snowshoe hare diets; spruce needles make up nearly 40% of the diet. 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. In Ontario, sugar maple (Acer saccharum), striped maple (A. pensylvanicum), red maple, other deciduous species, northern white-cedar (T. occidentalis), balsam fir, beaked hazelnut (C. cornuta), and buffaloberry were heavily barked. 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 Newfoundland, paper birch is preferred. Further details on regional food preferences are summarized in Snowshoe hare and allies: Spring, summer and autumn In Alaska, snowshoe hares consume new leaves of blueberries (Vaccinium spp.), new shoots of field horsetails (Equisetum arvense), and fireweed (Epilobium angustifolium) in spring. Grasses are not a major item due to low availability associated with sites that have adequate cover. In summer, leaves of willows, black spruce, birches, and bog Labrador tea (Ledum groenlandicum) are also consumed. Black spruce is the most heavily used and the most common species in the area. Pen trials suggest black spruce is not actually preferred. Roses (Rosa spp.) were preferred, but a minor dietary item, as they were not common in the study area. == Population cycles ==

(yellow, background) and Canada lynx (black line, foreground) furs sold to the Hudson's Bay Company. Canada lynx eat snowshoe hares. Northern populations of snowshoe hares undergo cycles that range from seven to 17 years between population peaks. The average time between peaks is approximately 10 years. The period of abundance usually lasts for two to five years, followed by a population decline to lower numbers or local scarcity. Areas of great abundance tend to be scattered. The hare's fluctuating numbers are modelled by the Lotka–Volterra equations. == Vulnerability to climate change ==

The habitat for some snowshoe hares has changed dramatically, leaving some habitats without snow for longer periods than previously. Some hares have adapted and stay brown all winter. Others, however, continue to turn white in winter. These hares are at an increased risk of being hunted and killed because they are no longer camouflaged. Many people in the scientific community believe that snowshoe hare populations are at risk of crashing unless interbreeding speeds up the process of evolution to year-round brown. Other species who rely on the hare as part of their diet are also at risk. == References ==