[Yellowstone National Park, Wyoming] In the winter months, when deep snow covers the sagebrush plains, hilltops, and scenic river valleys of Yellowstone National Park, bison abandon their trails and smaller traces and instead travel upon the park’s plowed asphalt highways. The animals have adopted the use of human highways for a simple reason. It is much easier for them to trek down a cleared, snow-free highway than it is to trudge off-road through several feet of snow. They expend far less energy moving from point A to point B, or from grazing site to grazing site. It is also safer for the big wooly mammals to move atop the paved highways. They can run faster from pursuing predators on the hard-surfaced roads. Plus, shy predators, such as wolves, are less likely to get close to the roadways for fear of coming into contact with homo-sapiens and their gawking, intrusive behaviors. It is likely that the plowed roads have increased the winter survivability rates of the park’s bison herds.
[North Central Wyoming] Interstate 90 between Buffalo, Wyoming, and Lodge Grass, Montana, skirts the old Bozeman Trail. Nineteenth century gold miners and settlers traveled over the Bozeman Trail from Fort Laramie to the gold fields of southwestern Montana or the fertile agricultural lands at the head of the Missouri River at the Three Forks. The Bozeman Trail cut through a rich ecological zone at the foot of the Bighorn Mountains. Countless elk, pronghorn, bison, and mule deer concentrated along the region’s stream valleys and wetlands, especially during the dry summer months and the bitter cold winter months. An abundance of game attracted bands of Native American hunters to the area, including the Sioux or Teton Lakota.
When European-Americans first arrived on the scene in the early 1860s, the Lakota fiercely resisted the presence of the white population. Lakota warriors sought to protect the game resource from trigger-happy European-Americans.
Although the Lakota lost their resistance war against the United States, the region still abounds in game. The bison herds are long gone, slaughtered by white market hunters in the late 1870s and early 1880s. However, elk still trod the Bighorns, while pronghorn and mule deer occupy the lower elevations adjacent to Interstate 90. Frequently, the mule deer attempt to cross I-90 along one of the region’s ancient trails. But the deer face a series of hurdles before they can reach the range on the far side of the superhighway. Animals must jump successive strands of barbed wire fencing, navigate deep, man-made ditches and culverts, and traverse four lanes of concrete, while avoiding the automobiles darting north and south atop the highway. Unfortunately, not all the deer succeed in making the crossing.
When a low-profile, sleek car hits a deer at 75 miles per hour, the deer is killed outright and often thrown onto the shoulder of the road or into the nearby ditch. Usually, the dead animal remains in one piece. But when a square-hooded semi-trailer truck hits a deer broadside at a high rate of speed, the animal will fall stone dead onto the road and the 18 wheels of the big rig will grind it into an unrecognizable lump of red meat, exposed intestines, and brown fur.
The road kill along I-90 northwest of Buffalo, Wyoming, feeds an assortment of creatures, including magpies, crows, ravens, bald eagles, and coyotes. These critters have altered their daily movements to take advantage of the dead animals strewn directly atop, or next to, the manmade highway. Rather than hunt and forage along the area’s ancient mammalian roads and trails within stream valleys and gullies, the scavengers now follow highways to locate carrion. Bald eagles and crows fly directly above traffic, landing when they find a carcass by the road. Coyotes trot through roadside ditches or next to the fences adjoining the superhighways until they find a road-killed creature. Yet, the same highway traffic that provides food for the scavengers also kills them. Cars and trucks hit animals that are feeding on road kill. Their smashed bodies then become food for still more scavengers.
There are ways to minimize road kill. Lowering the speed limit in the hours before and after dawn and dusk (when animals are most on the move) is the easiest and least expensive means of reducing the number of animals killed by vehicles. Constructing safe crossings for the animals (either above or below the highways) is another effective method for decreasing the amount of road kill.