One of the planet's biggest migrations has begun, as millions of red crabs march from the jungle to the sea for the spectacular phenomenon on Christmas Island. The annual crab migration typically occurs in October or November, at the start of the wet season. But rainfall came late this year, affecting the timing of their movement. Christmas Island has a mounting red crab population, doubling in the last five years from 50 million to more than 100 million. #christmasislandcrab #christmasisland