A conservation group hopes to raise $2 million in three months to buy a critical piece of property along Wyoming’s mule deer migration route. At 150 miles, it’s believed to be the longest mule deer migration route in the world. Luke Lynch is with the Conservation Fund, the group raising money to buy the 364 acres, which creates a kind of migration-bridge for the deer to cross between Fremont Lake and the city of Pinedale. As many as 5,000 deer must cross the bottleneck single file there. Lynch says such routes need to be preserved because they’re so rare.

“There probably were hundreds of long-distance migrations like these. Because of development and construction of highways and other impacts of man, there are only a few migrations like this left in the Western U.S. and this is the longest one there is.”

Mule deer numbers have been dropping drastically in the last few decades and protections of the route are one of many efforts being made to help the species.