50 Million Red Crabs to Migrate from Land to Sea in Christmas Island

Once a year, Christmas Island gets to witness an amazing feat of nature – an estimated 50 million red crabs getting out from their burrows in the forest and walking down the road to get to the sea for spawning season. After these crabs mate and unload their eggs into the sea, they walk back to their homes in the forest.

Millions of crabs crossing the road

Crabs everywhere…

Baby crabs in the sea…

Baby crabs returning from the sea…

What’s even more amazing is how the folks in the island prepare for the migration. You see, the safety of these red crabs is actually a big deal for people in Christmas Island. They’ve seen how human traffic can harm the crabs walking down the road. So before the migration starts, they take measures to make sure that the crabs get to their destination safely. This year, the Christmas Island National Park took care of 20 kilometers of barriers, 31 underpasses and 1 bridge to get ready for the great crab migration.

According to Rob Muller, Chief Ranger of Christmas Island National Park, “Rangers begin preparing for the migration around the beginning of August when the dry season is well under way and there is time to complete the work before the wet season rain comes. We try to have everything in place by mid October. That way we’re ready if the crabs decide to start migrating with the first decent rain, which can be in October, though it is more common that rain comes from November on.”

Putting up the 20 km permanent barrier.

The permanent fence leads to an underpass.

Rangers clean out the underpasses of dirts, leaves and vegetation that accumulated since the last migration

A Bobcat loader is used to remove the built up dirt and clear the entrances to the underpass.

Roads are closed to let crabs walk safely…

Bridge for crabs…

“The main way we try to protect crabs during the migration is to stop them being squashed by vehicles on the roads. But they still need to be able to cross roads to get to the sea. The best way to do this is to close the roads, but this is impractical for some of the main roads that go through the national park. So on the roads that are kept open we put up special fences to act as a barrier to keep the crabs off the road. But then we still need to let the crabs get across the road so we have installed underpasses in the roads that the crabs use to get to the other side.”

Right now, the people at Christmas Island are eagerly waiting for the start of the migration. You can check out their Facebook page for updates.