Pronghorn Migration: Welfare on the Last Great American Corridors

Pronghorn undertake the longest land migration in the lower 48 US states, but their ancient corridors face increasing fragmentation from fencing, development, and energy infrastructure.

Key Facts

Pronghorn (Antilocapra americana) migrate up to 300 miles annually between summer and winter ranges in Wyoming.
Pronghorn cannot jump over standard livestock fencing and must crawl under it — a significant barrier in fragmented landscapes.
The Path of the Pronghorn in Wyoming is the longest remaining mammal migration corridor in the lower 48 states.
Energy infrastructure including oil and gas wells, access roads, and pipelines has fragmented key migration corridors.
Modified fencing with raised bottom wire (at least 18 inches) allows pronghorn to pass safely underneath.
Wildlife crossing structures on US-191 in Wyoming reduced pronghorn mortality by 80% at that location.
Climate change is altering the timing of pronghorn migration relative to vegetation green-up, creating nutritional mismatches.

Welfare Considerations

Pronghorn migration welfare is primarily determined by corridor quality and continuity. Animals attempting to migrate through fragmented corridors encounter barriers — fences, roads, and development — that impose significant energy costs and mortality risk. Pronghorn stopped by impassable fencing in winter may starve or freeze when unable to reach lower-elevation winter range; those that attempt to cross highways risk fatal collisions. The welfare benefit of maintaining and restoring migration corridors is substantial: animals able to complete their annual migration reach superior winter range in better body condition, with lower vulnerability to starvation. The solutions are well established — fence modifications, wildlife crossing structures, and corridor easements — and have demonstrated dramatic effectiveness in reducing migration-related mortality.

What You Can Do

Support the Path of the Pronghorn and similar corridor protection initiatives in the western US.
Advocate for fence modification programs that raise bottom wire to allow pronghorn passage on public and private land.
Support wildlife crossing construction on key migration route highways including US-191 in Wyoming.
Oppose energy and development projects that would fragment remaining pronghorn migration corridors.
Engage with the Wyoming Game and Fish Department on pronghorn migration monitoring and corridor protection programs.