Each year in Wyoming a herd of pronghorn makes the longest land-mammal migration in the continental United States, moving between calving grounds in Grand Teton National Park and wintering areas north of Yellowstone National Park. The pronghorn have made the same 150-mile journey for centuries beyond memory. Now, their ancient migration corridor is threatened by development. At one point near Pinedale, WY, the animals’ route is squeezed between the Green River and suburban homes. After slipping through this spot, the pronghorn – an animal similar to the antelope – must weave through a busy highway crossing. The recent boom in natural gas extraction in the Rockies has made the migration of the 300-animal herd even more arduous.
How arduous? In 2008 and 2009, Joe Riis, a 26-year-old photographer, and Emeline Ostlind, a journalist and naturalist, followed the pronghorn to illustrate the herd’s increasingly perilous journey through its migration corridor. Using camera traps to trigger the shots and a wide-angle lens to capture the details of both the subject and its surroundings, Riis was able to get images of startling intimacy. His photographs show the pronghorn amid the snow of the mountains’ late-coming spring and traversing arid slopes at the end of summer. They also reveal the depth of the pronghorn’s plight – their apparent confusion when negotiating a barbed wire fence, a panic as they sprint through traffic.
As Riis and Ostlind tour the West presenting their research, word about the animals’ difficulty is getting out. Some landowners along the migration route are making small improvements, such as putting in wildlife-friendly fencing that allows the pronghorn to crawl underneath the wire rather than trying to hop over – a dangerous option for these poor jumpers. Although modest, the changes are important. After all, it’s our oversized footprint that has made the pronghorns’ already-difficult odyssey through a route they’ve followed since the last ice age so much harder. The least we can do is allow them to pass through.
Joe Riis, a National Geographic Young Explorer, works with Freedom to Roam, an organization that works to preserve wildlife corridors. You can view more of his work at www.joeriis.com.