Moving Up in the World

Migrations don’t always stretch across long distances. Sometimes, they don’t stretch across at all. Some migrations move up and down.

Dall sheep live in some of the most rugged and hostile terrain in North America. They shift habitats as the seasons change. But theirs is a vertical migration.

In spring and summer, Dall sheep graze in high-mountain meadows and on open slopes. They nibble on grasses and a wide range of other plants that are plentiful in summer.

As winter approaches, the sheep begin to move down the mountain. How do they know the way? Scientists think that the migration path is passed on from generation to generation. The old teach the young.

The oldest sheep usually begins the migration and leads the others. They follow the elder as they pick their way down through the rocky cliffs, one careful step at a time. Together, they descend about 1,200 meters (about 4,000 feet).

These sheep are not great wanderers. Most spend their entire lives in this narrow band, up and down the mountain. In winter, they eat woody plants such as willow, sage, cranberry, and crowberry which they can find in the snow. They remain here until the oldest sheep leads them back up the mountain in spring.