Biology Reference
In-Depth Information
ates, and what filters down to the ground is so fine that snow depth is much reduced. This, of course,
greatly facilitates travel by the deer.
In addition, the dense evergreens break the wind and cut wind chill a great deal, and they reduce
radiational cooling at night. There may also be an added thermal benefit from mature softwood cover,
because the dark evergreens absorb heat from the sun and make a small but crucial difference in the
temperature below.
A second attribute of a good wintering area is a south- or southwest-facing slope so that the low-ly-
ing winter sun in afternoon strikes more directly, and hence provides more heat. Deer also manage if
the terrain is flat, but won't select wintering areas on north- and northeast-facing slopes.
The whitetail's final defense against winter is a reduced metabolic rate. This helps them conserve
energy when food is scarce and the cold is severe. Even with all these adaptations, however, winter
is a dangerous and often deadly time for whitetails. In northern climates, even under good conditions,
they lose a substantial amount of weight, and when that loss approaches one-third of their body weight,
death from outright starvation and causes related to severe malnutrition begin to set in.
A prime wintering area contains patches of mature softwoods interspersed with smaller openings
that provide younger trees for browse—ideally, hardwoods or white cedar. However, because of their
reduced metabolic rate, whitetails can endure several weeks in winter with little or no food, provided
they aren't disturbed. As soon as deer become nervous and agitated, their metabolic rate rises; if the
deer are forced to take flight, energy consumption becomes even greater. That's why winter recreation-
ists such as cross-country skiers, snowshoers, and snowmobilers should avoid deer wintering areas.
Despite all these adaptations, a harsh winter will still take a substantial toll of whitetails. Some deer
die even in a mild winter, but many fawns, as well as some older deer, succumb during a severe one. In
fact, life in the wild at any season is extremely hazardous for deer. Ask a room full of people how long
they think an
average
deer lives in the wild, and many will guess fifteen years, twenty, or even more.
They're grossly overestimating. Although a small percentage of deer live into their teens, the vast ma-
jority die much sooner, and the average life span of a whitetail is only about two years!
No account of the hazards of winter would be complete without mention of the damage caused by
roaming domestic dogs. When confronted by the fact that their small dogs are “running deer” (the col-
loquial phrase for pursuing deer), many owners bridle and say, “Why, Fido and Fifi wouldn't hurt a
fly—and besides, they're far too small to damage an animal as big as a deer.”
This is a huge misunderstanding. True, someone's little terrier, spaniel, or beagle can't attack a deer
and bring it down by brute strength, but it can easily run a deer to exhaustion in the winter, especially
if the snow is deep. When a deer finally drops from fatigue, even small dogs may begin to gnaw on it
while it's still alive—and even if they break away from the chase and head for home, an exhausted deer
is often so stressed that it won't recover.
Roaming dogs taught our children at an early age a harsh lesson in the damage that dogs can inflict
on deer, as well as in the hard realities of the natural world. In order to take the school bus, the children
