MovingUpintheWorld

Migrationsdon’talwaysstretchacrosslongdistances.Somemigrationsmoveupand down.

Dall sheepliveinruggedlandinNorthAmerica.Theymoveastheseasonschange.Theirmigrationgoesupanddown.It’scalledaverticalmigration.

Inspringandsummer,Dallsheepgrazeinhigh-mountainmeadowsandonopenslopes.Whenwintercomes,thesheepmovedownthemountain.Howdotheyknowtheway?Scientiststhinkthatthepathispassedonbyparentstotheiryoung.

Theoldestsheepusuallybeginsthemigration,leadingtheothers.Theyclimbabout1,200meters(about 4,000feet) downrockycliffs.Mostspendtheirentirelivesinthisnarrowband,movingup  anddown.