本文选自《新科学人》，揭秘猛犸象的“环球”之旅。

MammothTusk（猛犸象象牙）AnalysisRevealsEpicLifetimeJourneyaroundAlaska

Mammothsareamongthebest-knowninhabitantsofthelasticeage,buttheirtravelsacrossthetundra（冻土带）havelongremainedamystery.Nowexpertshaveusedthechemical