Red Crabs Swarm Island: Christmas Island in Australia Shows Migration of Creatures who Only Move when it's Raining (VIDEO)

If you visit Christmas Island in Australia, you may have spotted the rare red crag migration that has been gracing the area from November to January. The Christian Science Report notes that the timing of the migration depends on the weather, as the crabs will only move when it is raining, and this year in particular, the crabs were slated to begin their migration in January.

Millions of the crabs made the journey from their homes in search of the sea. The male crab usually begins the migration cycle, they are the first to arrive at sea although they are quickly joined and then outnumbered by female crabs according to National Geographic. 

However,  females stay behind to produce eggs after mating with male crabs. Male crabs will take 1 to 2 days to make it to sea. When the female crabs arrive, it takes 5 to 6 nights for them to release their eggs into the sea.

"They descend cliffs, climb banks and maneuver around obstacles to reach the shoreline and lay their eggs, eventually returning to the island's central plateau with their offspring in tow," a CNN report described, listing the event as "One of the Most Spectacular Migrations" in a recent March report.

Expeditions to witness the migration can cost upwards of $1,500.

Want to learn more about the crabs? Check out this video, courtesy of YouTube.