Great Migrations: Episode 3: Survival of the Fastest NGC-US: Episode Code: 3592 NGCI: IBMS – 023560

Beginning their journey off the Alaskan coast, the Pacific walrus – whose bodies are not made for swimming long distances – have used ice floes for eons as sanctuaries for rest and breeding as they journey to Russia and back. But in recent years the floating ice chunks have become fewer, smaller and unable to sustain the walrus population that struggles to occupy these insufficient life rafts.

(Photo Credit: © PAUL NICKLEN/ National Geographic)