Red wolves once ranged far and wide across the U.S., helping them earn the nickname “America's wolf.” But there are now thought to be fewer than 20 left in the wild. And in North Carolina, the only place where the animals roam free, motorists are the biggest threat to their survival. For decades, conservationists have pushed for changes to U.S. 64, a busy two-lane highway that runs straight through the Alligator River National Wildlife Refuge. They may finally be getting their wish with federal funding that backs small underpasses to steer wolves and other animals below the highway. Wildlife crossings have surged around the world in the past two decades, but the one in North Carolina is a little different because it seeks to save a critically endangered species.