Caribou undertake the longest land migrations of any mammal, with some herds traveling 5,000 kilometers annually. Industrial development and climate change are disrupting the calving grounds essential for population persistence.
Caribou welfare during migration is primarily affected by energy balance - successful migration requires arriving at calving grounds with sufficient body condition for calving and early lactation. Disruptions that increase energetic cost (additional detours around industrial development) or reduce forage quality (climate-driven phenological mismatch) compromise welfare by forcing animals into negative energy balance. Pregnant females who cannot adequately provision themselves and their calves produce calves with lower birth weights and survival rates. The welfare of newborn calves who are abandoned when disturbance drives mothers from calving grounds is direct and acute. Indigenous-led monitoring of caribou welfare integrates traditional ecological knowledge with scientific assessment in ways that benefit both caribou and communities.