Millions of migrating crabs trigger road closures

Australia's Christmas Island has a bad (or maybe it's good?) case of the crabs. Right now, millions of red crabs are migrating from the forest to the Indian Ocean to breed. The mass movement requires officials to close off roads to allow the crustaceans to pass. The annual event begins with the first rainfall of the year. From Parks Australia:

Red crabs all over the island leave their homes at the same time and start marching towards the ocean to mate and spawn. Male crabs lead the migration and are joined by females along the way.

The exact timing and speed of the migration is determined by the phase of the moon. Red crabs always spawn before dawn on a receding high-tide during the last quarter of the moon. Incredibly, they know exactly when to leave their burrows to make this lunar date.

However, because crabs wait until the first rainfall to start their trek, they sometimes have to hurry. If the rains arrive close to the optimal spawning date, they will move rapidly. But if the rain comes early they may take their time, stopping to eat and drink on their way to the coast.

"Our staff have been out managing traffic, raking crabs off roads and providing updates to the community on road closures," Parks Australia tweeted.

images: Parks Australia