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Why Did the Pronghorn Cross the Road?

Migration isn't just for the birds anymore.

Everyone knows how it works. Every year millions of animals migrate south to seek warmer weather. Some move a great distance, some a smaller one to a slightly less frigid climate. It's not uncommon to see a formation of geese gliding across the sky, relatively safe so long as they avoid airports.

It's the less conspicuous animals, however, who are in the most danger. Those creatures who cannot fly above highways have a far more perilous road ahead of them, and sometimes they need human help to reach their destination.

No matter how cautious a driver is, there is always the real and present danger of an animal darting suddenly in front of their vehicle, causing a potentially fatal accident for both the human driver and the animal. This is especially hazardous for the pronghorn, an antelope-like creature native only to North America. They have the widest migration range of any land mammal in North America, and are also the fastest running animal on the continent.

Once a thriving species, their numbers as high as 35 million in the 19th Century, the pronghorn have become yet another species to fade from our landscape. Only about 700,000 pronghorn remain in the wild, and each year those numbers stand to dwindle further during their migration to Wyoming's Upper Green River Basin. The 93-mile trek is one the species has traveled for the last 6,000 years, and the pronghorn aren't likely to alter their course any time soon.

With numbers decreasing, there is a very real danger of losing the species to the endangered list.

How, then, could they be protected from the threat of accidents on the road?

The solution, ultimately, was quite simple. When human traffic becomes too congested, alternate routes in the form of overpasses and underpasses provide relief. So the Wyoming Department of Transportation did just that.

Along 13 miles of Highway 191, chosen carefully based upon five years of GPS tracking data, two overpasses and six underpasses were built to accommodate the animals. As it turns out, what is good enough for a car is good enough for a pronghorn.

The pronghorn were understandably leery of these new passes at first. During that first year in 2012, many took hours to finally travel the new route. Some traveled back and forth several times, untrusting of their new road.

Only a year later, however, the pronghorn take to the new wildlife passages like pros. The Wildlife Conservation Society (WCS) has been monitoring the migration, and has declared a second season of success. The pronghorn no longer display any hesitation at all before tackling their new migration routes, as comfortable as though it had been this way for thousands of years.

Better yet, other migrating animals have been able to take advantage of this new and safer alternative to the dangerous bottleneck effect that occurs on Highway 191. Mule deer, moose, elk and even local livestock traveling during seasonal drives have safely traversed these new wildlife passages without the stress or anxiety that comes with dodging speeding cars.

In fact, it makes the crossing safer for humans, too. During migration season, the number of car accidents directly resulting from animals in the road rises sharply. In helping these animals, we not only help them to survive, we help ourselves for years to come.

According to the Boone and Crockett Club, the pronghorn has become the second most-prevalent game animal in the country after deer. Hunting pronghorn is legal in nearly every western state.

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Why Did the Pronghorn Cross the Road?