This is scientific Americans 60 Second Science. I'm Jason Goldman. Ever hear of the

prong horn antelope in the American West? Well it's not really an antelope

it's actually more closely related to giraffes than to true antelopes.

And the last known migration of prong horns occurs between Grand Titan National Park

and the Upper Green River Basin in Western Wyoming.

The so-called path of the prong horn stretches more than 150 miles and is one of the longest

mammal migration corridors that remains in North America.

That stretch is also the only federally designated wildlife migration corridor.

The trouble is that the corridor intersects with roads and fences. The officials built eight wildlife crossings along some 12 miles of U.S. Highway 191, two overpasses and six underpasses.

But having a crossing doesn't mean that wildlife will use it. So researchers decided to assess the impacts of

the 9.7 million dollar investments.

We're out in the field on spotting scopes watching these animals as they're approaching brand new structures and

this was just a perfect setting because we had been studying these pronghorn

these animals on their long distance migration for, I don't know, about a decade.

Wildlife Conservation Society biologist Renee Sidler, now at the Idaho Department of Fish and Game.

She focused her observations on an area called Trapper's Point.

Twice a year, between 1 and 2,000 prong horn,

along with some 3,000 mule deer, passed through this area.

Archaeological evidence indicates that Pronghorn have been moving through Chaper's

Point for at least 6,000 years. But now they have to contend with highways and fast cars.

Before the wildlife crossings were built, the 12 miles of the 2-lane Highway 191 saw an average of 85 animal vehicle collisions each year.

We looked at how many times an animal would attempt to use the crossing structure before they were able to successfully get to the other side and

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