National Geographic Today
Each spring and fall, hundreds of tan-and white-pronghorn antelope participate in one of nature's most spectacular choreographed rituals: their seasonal migration between high mountain summer range and lowland winter range.
This doesn't take place in Africa's Serengetiit happens in the American West, in western Wyomingand it is the longest migration of any land mammal in the lower 48 states. The antelope pass through what conservationists call "one of the most intact mountain environments on Earth," home to an abundance of bison, grizzly bears, cougar, elk, red fox, lynx and many more species.
But biologist's surveys over the last decade have found that this particular antelope population has plummeted from between 400-500 animals in 1991 to about 158 last year.
Civilization is crowding in on this herd and threatening their very survival. Development and other human activity has narrowed the animal's migration route down to a couple of hundred yards in some areas.
Saving this migration poses a set of complex challenges to conservationists and officials in national parks and wildlife agencies. "There is a need for a designated migration corridor to help ensure the survival of this population of pronghorn," says Bill Weber, director of the North American program for the Wildlife Conservation Society (WCS) in New York City.
"Archaeological records show that their migration has gone on for at least 6,000 years," he said. The antelope migrate up to 200 miles, summering in Grand Teton National Park and wintering in the Red Desert.
Pronghorns are the only American antelope species, and are the sole surviving member of its ancient family. They have slender, graceful deer-like bodies, standing three and a half feet high at the shoulder.
They have three unique characteristics: they are the fastest animal in the Western hemisphere, running at speeds up to 60 m.p.h. They are the only animal in the world with branched hornsmales sport distinctive 12-inch pronged horns that give the species its nameand they are the only creature to shed those horns seasonally, like antlers.
Once, the antelope were as plentiful as bison throughout the West; today they number a few hundred thousand, from Montana to Arizona.
The species itself is not endangered. But this particular Wyoming herd is at risk, along with its migration, posing a particularly difficult conservation challenge.
SOURCES AND RELATED WEB SITES