MovingUpintheWorld

Migrationsdon’talwaysstretchacrosslongdistances.Sometimes,theydon’tstretchacrossatall.Somemigrationsmoveupand down.

Dall sheepliveinsomeofthemostruggedandhostileterraininNorthAmerica.Theyshifthabitatsastheseasonschange.Buttheirsisavertical migration.

Inspringandsummer,Dallsheepgrazeinhigh-mountainmeadowsandonopenslopes.Theynibbleongrassesandawiderangeofotherplantsthatareplentifulin summer.

Aswinterapproaches,thesheepbegin tomovedownthemountain.Howdotheyknowtheway?Scientiststhinkthatthemigrationpathispassedonfromgenerationtogeneration.Theoldteachtheyoung.

Theoldestsheepusuallybeginsthemigrationandleadstheothers.Theyfollowtheelderastheypicktheirwaydownthroughtherockycliffs,onecarefulstepatatime.Together,theydescendabout1,200meters(about4,000 feet).

Thesesheeparenotgreatwanderers.Mostspendtheirentirelivesinthisnarrowband,upanddownthemountain.Inwinter,theyeatwoodyplantssuchaswillow,sage,cranberry,andcrowberrywhichtheycanfindinthesnow.Theyremainhereuntiltheoldestsheepleadsthembackupthemountainin spring.