Millions of red crabs scuttled across an Australian island in their annual migration from forests to the ocean.Footage shows a sea of Christmas Island red crabs crawling over various terrain in order to reach the coast, where they mate and spawn.Beginning with the first rainfall of the wet season, the migration usually starts in October or November, but can be as late as December or January.The phenomenon's timing and speed is determined by the phase of the moon.To protect the crabs, roads may close at the last minute so as not to disturb the migration.SWNS