In a winter with little snow, a snowshoe hare loses the benefit of camouflage. (iStock photo)
We have had another up-and-down winter, with plenty of wind and record tides bedeviling coastal landowners. Temperatures have bounced around and we have experienced heavy rains. Snow has been limited, with a dusting in early December and just a few inches in January and February. Except for those who make a living plowing the white stuff, or folks keen to get out the snowshoes, the lack of snow is of little concern to most of us.
Not so for the snowshoe hare, who in autumn traded his rusty brown hair for a brilliant white winter coat. These diminutive creatures are nearly defenseless in a world full of predators, so they rely on camouflage to make it through the winter. Imagine how tough that is when there is little snow on the ground. An animal that prefers to hide out in thick cover now shines like a snowball in hell, with about the same odds of survival. Run, baby, run!
The snowshoe hare, scientific name Lepus americanus, is built for speed, unlike our endangered New England cottontail and the eastern cottontail, members of the Sylvilagus genus. Long back legs allow leaps up to 10 feet at speeds of more than 30 miles per hour in short bursts, enough to outrun most predators but at the cost of precious energy in the winter. Its feet are heavily furred for insulation, with special, stiff hairs on the hind feet allowing extra traction in snow. If the hare decides to hide in snow, only its black eyes and a black rim on the ears might reveal its position.
The hare prefers habitat with extensive plant coverage, with an emphasis on coniferous forests over more open deciduous stands. Their diet consists of grasses, forbs, ferns and leaves, but in winter it transitions to eating twigs, needles and bark in the absence of greenery. Hares spend their days hidden in thick, brushy cover to protect them from airborne predators such as raptors. They are active in the early and late hours of the day, but most feeding is done at night. As with other small mammals, hares do not hibernate, needing food every day to survive bitter cold.
As a favored meal for Canada lynx, bobcats, coyotes, fishers, foxes and martens, the snowshoe hare responds with a high birth rate. The female, or doe, may deliver four litters each year with up to seven young, called leverets, per litter. Scientists have long studied the population swings of the hares, known to experience peaks and valleys in their numbers over cycles averaging 10 years. In boom years, there may be as many as 1,000 hares per square mile, allowing predator populations to swell. But when hare populations crash, predators also experience substantial losses.
Snowshoe hares once roamed as far south as North Carolina and central California, to northern Canada and Alaska. But they are no longer found in many parts of their southern range, states like Ohio and Maryland, partly because of habitat loss but also because of climate changes. Along with 20 other species of birds and mammals that change color seasonally, there are many questions about the long-term prospects for the hares as winters recede. Scientists predict that the snowpack will be present up to 35 fewer days by 2050 and as many as 69 fewer days by 2100. Will the snowshoe hare be able to adapt?
The hare’s coloration is based on its genetics, with the number of daylight hours (photoperiodism) the key determinant to when they change from brown to white and back again. An article by John Litvaitis in Northern Woodlands reported that studies in Montana on radio-collared hares demonstrated that if springtime snows melted rapidly, hares were able to molt more quickly to their summer colors. But there are limits to this ability, leading to mortality rates up to 10% higher for hares with a coat color different from the surrounding habitat. While snowshoe hares in some Western states with limited snow may remain brown in the winter, an adaptation of this sort would require hundreds if not thousands of years to occur.
Michigan studies determined that in just 20 years, the southern limit of snowshoe hare populations shifted north by roughly 30 miles. If current weather changes continue, a similar impact on our hare population seems likely. Since the hare plays a vital role in the forest food chain, a permanent decline in their numbers will be bad news for many of our predator species.
Ed Robinson’s latest book, “Nature Notes from Maine Vol. II: Puffins, Black Bears, Raccoons & More,” is available from the Harpswell Heritage Land Trust. All profits support HHLT’s conservation and education efforts.
