Moving Up in the World

Migrations don’t always stretch across long distances. Some migrations move up and down .

Dall sheep live in some of the most rugged, hostile land in North America. They move 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.

Before winter comes, the sheep move down the mountain. How do they know the way? Scientists think that the path is passed on from generation to generation.

The oldest sheep usually begins the migration and leads the others. They descend about 1,200 meters (about 4,000 feet) down rocky cliffs.

Dall sheep are not great wanderers. Most spend their entire lives in this narrow band, up and down the mountain.