Caribou have one of the longest annual migrations of any land mammal in the Arctic. Different herds travel between seasonal ranges, sometimes covering more than 1,000 kilometres in a year.
Caribou migrate between wintering grounds and summer calving areas in response to snow conditions, plant growth, insect pressure, and the needs of pregnant females. Their broad hooves help them walk across snow, tundra, and wetlands, while their specialized noses warm and humidify cold air.
Caribou are the wild form of the species commonly called reindeer in Eurasia. Unlike most deer, both male and female caribou grow antlers. Migration distances vary widely between herds and years, so no single route represents every population. Some herds have experienced major declines because of changing climate, habitat conditions, predators, and human disturbance.