Mandatory Credit: Photo by James D. Morgan / Rex Features (1254772h) Migrating red crabs on Christmas Island Red crab migration on Christmas Island, Indian Ocean - 01 Dec 2010 One of the most amazing migrations in the animal world takes place each year on Christmas Island. This annual event sees millions of red crabs swarm across the island in the hope of making it to the sea. Christmas Island lies some 1600 miles north west of Perth in the middle of the Indian Ocean. While just 1500 people live there it is home to an estimated 120 million-strong crab population. Most of these are red crabs, which spend most of their time living in burrows on the rainforest floor in order to avoid drying out in the fierce sun. But when the time is right - according to the tides and phases of the moon - they embark on the journey of their lives. The crabs spend several painstaking days crawling to the ocean, which can be as far away as 9km. Along the way, from the interior of the island to its coast, they face numerous hazards and up to half a million never return from their perilous journey. Once they reach the ocean the crabs mate and the females produce eggs, which they later release into the sea