I GREW UP IN Littleton, Colorado, a suburb of Denver that was forcefully inserted into miles of open prairie land back in the late ’80s. This is where the sprawling eastern plains meet the Hogbacks, the very beginnings of the Rocky Mountains. 25 years later, we still have more open space than most areas of suburban Denver, but the buildup of a major highway and a network of suburbs has disconnected the deer, coyotes, bears, and mountain lions from their natural thoroughfare between the plains and the mountains.
Before the buildup, baby deer would run down the street in the morning if you could wake up early enough to catch them, and coyotes howled every night. Nowadays such sightings are rare, and the vast majority of these animals either won’t risk the highway, or get hit by cars in the process. The first elk I’ve seen in years made his way into the neighborhood this summer to snack on our neighbor’s unmowed lawn, and he looked mightily confused about how he managed the maneuver.
Here are 6 ingenious wildlife crossings that help make the journey as natural as possible for the four-legged travelers of the world. 
