Natural World - Season 22 Episode 10

Across the top of North America, millions of caribou are led on their never-ending journey by the mothers of the herd. Driven by the demands of motherhood, they travel 3000 miles on a trek from their winter range at the edge of the northern forests to calving grounds and back again. The caribou keep themselves to open ground for visibility of their predators. The wolves are not far behind.