Caribou undertake some of the longest land migrations on Earth. Infrastructure, industrial development, and climate change are fragmenting these journeys with serious welfare and population consequences.
Caribou migration welfare is shaped by the complex interaction of natural migration biology and increasing human footprint in their arctic and subarctic range. Migration allows caribou to exploit seasonal nutritional resources across vast landscapes — preventing completion of migration through linear infrastructure creates nutritional stress and increased calf mortality. The calving period is particularly welfare-sensitive: females disturbed during calving show reduced calf survival, and displacement from historical calving grounds into suboptimal habitat reduces the nutrition available during this critical period. Industrial seismic lines — now numbering in the tens of thousands in Canada — provide wolf highways that increase predation mortality across vast landscapes. Climate change is altering the timing of Arctic plant green-up — when caribou arrive expecting lush vegetation they encounter late-emerging or drought-stressed plants, a phenomenon called phenological mismatch that causes nutritional welfare harm. Comprehensive habitat protection including seismic line reclamation and development setbacks from calving grounds are the most evidence-based welfare interventions.