The snowshoe hare (Lepus americanus), also called the varying hare or snowshoe rabbit, is a species of hare found in North America. The "snowshoe" moniker refers to the hare's large hind feet, which prevent it from sinking into soft snow, much like snowshoes.
The hare has two seasonal coats which aid in camouflaging the animal. In summer, the hare is covered in short, brown fur; in winter this is exchanged for a longer coat of white fur. The name "varying hare" refers to this seasonal change in appearance.
A major predator of the snowshoe hare is the Canada lynx. Historical records of animals caught by fur hunters over decades 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.
Taxonomy and etymology
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:Hall, E. Raymond. (1981). The mammals of North America. 2nd ed. Vol. 2. New York: John Wiley and Sons. .
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 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.Bittner, Steven L.; Rongstad, Orrin J. (1982). "Snowshoe hare and allies". In: Chapman, J. A.; Feldhamer, C. A., eds. Wild mammals of North America: biology, management and economies. Baltimore, MD: The Johns Hopkins University Press. pp. 146–163. . 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.Harper, Kimball T.; Wagstaff, Fred J.; Kunzler, Lynn M. (1985). Biology management of the Gambel oak vegetative type: a literature review. Gen. Tech. Rep. INT-179. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station 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.DeGraaf, Richard M.; Yamasaki, Mariko; Leak, William B.; Lanier, John W. (1992). New England wildlife: management of forested habitats. Gen. Tech. Rep. NE-144. Radnor, PA: U.S. Department of Agriculture, Forest Service, Northeastern Forest Experiment Station 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.Campbell, Dan L. (1982). "Influence of site preparation on animal use and animal damage to tree seedlings". In: Baumgartner, David M., compiler. Site preparation and fuels management on steep terrain: Proceedings of a symposium; 1982 February 15–17; Spokane, WA. Pullman, WA: Washington State University, Cooperative Extension: 93–101 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 western Oregon, snowshoe hares were abundant only in early successional stages, including stable brushfields.Allen, Hollis Howard. (1969). The inter-relationship of salmonberry and Douglas-fir in cutover areas. Corvallis, OR: Oregon State University 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. Moonlight increases snowshoe hare vulnerability to predation, particularly in winter. They tend to avoid open areas during bright phases of the moon and during bright periods of a single night. 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.Banfield, A. W. F. (1974). The mammals of Canada. Toronto: University of Toronto Press 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.Giusti, Gregory A.; Schmidt, Robert H.; Timm, Robert M. et al. (1992). "The lagomorphs: rabbits, hares, and pika". In: Silvicultural approaches to animal damage management in Pacific Northwest forests. Gen. Tech. Rep. PNW-GTR-287. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. pp. 289–307. 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.Maser, Chris; Mate, Bruce R.; Franklin, Jerry F.; Dyrness, C. T. (1981). Natural history of Oregon Coast mammals. Gen. Tech. Rep. PNW-133. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station
Reproduction