Lepus americanus - Snowshoe Hare

Skull Pictures:                
Dorsal     Mandible
Lateral     Posterior Mandible
Ventral

Physical Description:

The snowshoe hare (Lepus americanus) or varying hare has an average weight of 1.4 – 2.3 kg with a total length of 380 – 505 mm (Burt 1948).  According to Livaitis (1990), they do exhibit sexual dimorphism, with the female being slightly larger than the males.  The color of the snowshoe hare is what gives it the name varying hare.  The color varies throughout the year depending on the presence or absence of snow.  During later spring, summer, and early fall, the hare is a brownish gray color while the remaining part of the year it is white to blend in with the snow (Burt 1948).  During this time the hare is all white except for the posterior surface of the ear which is tipped black (Hazard 1982).

The teeth and skull of the snowshoe hare have very distinct characteristics including evergrowing incisors (Hazard 1982).  The dental formula of the snowshoe is I 2-2/1-1 C 0-0/0-0 P 3-3/2-2 M 3-3/3-3 =28 (Burt 1948).  Since the snowshoe has no canines, they exhibit a diastema or a gap between the incisors and premolars (Hazard 1982).  The distinctive characteristic of the teeth is the presence of a second pair of small peglike incisors directly behind the first pair (Hazard 1982).  The chief characteristic of the skull is that the supraorbitals are not fused posteriorly with the frontals, but instead flare out posteriorly while the interparietal is fused to the parietals (Hazard 1982). 

Distribution:

The snowshoe hare ranges as far north as the treeline in Northern Canada and Alaska and southward into the southern Rocky Mountains, Great Lakes Region, and the Appalachian Mountains of the U.S. (Murray 2000).  As previously mentioned, the northern range is controlled by the treeline while the southern range is controlled by snow cover and predation (Murray 2000).

The snowshoe inhabits mainly Northern Wisconsin, but does extend into Central Wisconsin.  According to Buehler and Keith, “the southern limit of the Snowshoe Hare distribution in Wisconsin, now and historically has been established mainly by predator caused mortality which can be significantly moderated by conifer cover and timely snowfalls” (1982).  The southern limit is often established by low predation rates and the presence of low conifers which provide wither food, protection from predators, and concealment from predators and inclement weather (Buehler and Keith 1982).

Ontogeny and Reproduction:

The timing of hare reproduction is greatly affected by photoperiod and ambient temperature (Murray 2000), while most of the breeding begins in March and continues into July (Hazard 1982).  The breeding season is the only time in which the snowshoe is social (Godin 1977) and at this time the female is dominant (Livaitis 1990).

The promiscuous snowshoe hare exhibits a courting behavior in which the buck chases the doe (Godin 1977).  During this courtship there is a series of chases and jumps and often the hares urinate on each other during the jumps (Kurta 1995).  The courting ends with the hares touching noses in which copulation takes place shortly after.  A pair of snowshoes may copulate several times within ten minutes (Godin 1977).

After fertilization, gestation usually lasts for approximately 36 days (Burt 1948).  The first young are usually born in May with typically two to four per litter and multiple litters in a year (Burt 1948).

At birth the young weigh 65 - 80 grams and are born fully furred with their eyes open (Kurta 1995).  Shortly after birth the young are able to move with little or no problems.  A female with offspring is not tolerable of any other females at this time (Hazard 1982).

After birth the young hide separate from their mother and only reunite with her a couple times daily for their feeding (Kurta 1995).  The young are weaned between six and eight weeks old in which they are close to their adult weights (Burt 1948).  Although they are close to their adult weights, Godin does not classify them as adults until the epiphyseal cartilage in the humerus disappears which usually occurs around eight months of age (1977).

Ecology and Behavior:

The habitats of most snowshoe hares include a heavily forested area with a dense understory and are usually coniferous and void of humans (Kurta 1995).  Buehler and Keith believe that habitats that continually support hare populations have one attribute in common, the presence of low dense woody vegetation (1982).  The areas they inhabit are often large undivided woods since the home range is approximately 25 square miles for males and 19 for females (Godin 1977).  Snowshoe frequency is also generally higher when cottontails are not present (Buehler and Keith 1982).

The snowshoe is largely crepuscular and nocturnal (Hazard 1982) and during these time are generally feeding.  Their summer food often consists of grasses, clovers, dandelions, aster, strawberry, ferns, and leaves of aspen, willow, and birch (Kurta 1995).  Their winter food is primarily composed of bark, twigs, and buds of maples, willows, poplars, and hazelnuts and also needles of conifers (Kurta 1995).  Kurta also noted that snowshoe hares will eat meat of animals they find dead or meat left in traplines (1995).  Due to their size, the browse line for these hares is one meter, but can reach two meters during the winter due to the snow pack (Hazard 1982).  Since these hares are hindgut fermenters, they demonstrate refection, which is a form of coprophagy to absorb more nutrients from their food (Godin 1977).

The locomotion of snowshoes is very quick due to their large powerful hind legs (Godin 1977).  During running the locomotion is digitigrade, but changes to plantigrade while hopping (Godin1977).  Their large, powerful hind legs enables them to run up to 27 mph and jump up to ten feet in a single bound (“Snowshoe Rabbit”).

Snowshoe hares, like all lagomorphs, are heavily preyed on.  The main predators for the snowshoe include man, foxes, lynx, bobcats, martens, fishers, weasels, great horned owls, snowy owls, goshawks, and red-tailed hawks (Godin 1977).  They are also infected with parasites such as ticks, fleas, mites, cestodes, nematodes, trematodes, and botflies (Godin 1977).  According to Kurta, no more than 15% of adults survive until the next year (1995).

Remarks:

Since the snowshoe changes colors, they exhibit a distinct molt.  The autumn molt which changes them white begins in September and ends in December.  The autumn molt follows the pattern which starts on the ears, feet, and legs and ends along the back.  The spring molt which changes the hare back to the brown color begins in March and ends in late May.  This molt too follows a distinct pattern, but starts with the forehead, muzzle, and body and ends on the ears and feet (Godin 1977).  The total transformation from one color to another takes approximately 72 days (Ryan).

The snowshoe hare also goes through a very pronounced ten year life cycle.  Although many studies have been done on this cycle, there is no definite answer to what causes it.  Some reasons hypothesized include increased predation, decreased reproduction, and a decrease of food and or habitat.  During the cycle, the population can go from one hare per square mile to a high of several hundred (Burt 1948).  The classic cycle no longer as pronounced in Wisconsin due to forest maturity, which has led to a decrease in the population (Buehler and Keith 1982).

Literature Cited:

Buehler, D.A., and L.B. Keith.  1982.  Snowshoe hare distribution and habitat use in Wisconsin.  Canadian Field Naturalist 96: 15-29.

Burt, W.H.  1948.  The Mammals of Michigan.  The University of Michigan Press.

Godin, A.J.  1977.  Wild Mammals of New England.  The Johns Hopkins University Press.

Hazard, E.B.  1982.  The Mammals of Minnesota.  University of Minnesota Press.

Kurta, A.  1995.  Mammals of the Great Lakes Region.  The University of Michigan Press.

“Lepus americanus.”  <http://animaldiversity.ummz.umich.edu/accounts/lepus/l._americanus$media.html>.  Accessed 4 December 2003.

Livaitis, J.A.  1990.  Differential habitat use by sexes of snowshoe hares.  Journal of Mammalogy 71(4):520-523.

Murray, D.L.  2000.  A geographic analysis of snowshoe hares.  Canadian Journal of Zoology 78(7):1207-1215.

Ryan, M.  The Snowshoe Hare (Lepus americanus).  The Mount Allison University website.  <http://www.mta.ca/~kvernes/mammalweb/sshare/sshare.htm>. Accessed 30 November 2003.

“Snowshoe Rabbit.”  <http://www.blueplanetbiomes.org/snowshoe_rabbit.htm>.  Accessed 1 December 2003.

Reference written by Clifford Ruland, Biol 378: Edited by Chris Yahnke. Page last updated