Christmas Island Crab Migration

I am very thankful that I don’t live on Christmas Island. While I would love to visit sometime, the reality of an annual migration of hundreds-of-thousands of crabs crossing the island twice is not for this explorer.  I have a hard enough time dealing with Palmetto Bugs on the Gulf Coast of the US.

Christmas Island crabs are land crabs that live in the rain forest and migrate to sea during perfect rain/moon sequence; usually between October and December, which means now (as of this article). They need a combination of the last moon quarter and a heavy rain with a high tide going out at night. The males go first followed by the egg sack-carrying females.  The islanders have constructed barriers near road ways to keep the crabs migrating without risking life on a roadway but some do breach the barriers and roads eventually end up closed for a short period of time.  Once at sea, the females release their eggs which go out to sea with the tide.  Shortly, these eggs hatch, the new crabs congregate on the shoreline to start breathing as land crabs and the migrating “families” return to the rain forest to live in their burrows until the next migration. Click here for a video of the action.  There are plenty of other videos on youtube showing the baby crab migration. Check them out as well.

These crabs know where they need to go and if you and your house are in the path, they’ll come right through. And on the way back, with the little ones following, it looks like a red, moving blanket of critters. There are places these crabs don’t crawl, so if I had to live there, I could choose a home far from the action.  But still, I am not into it. The migration is a really cool event in a nightmare-ish sort of way.

Meanwhile, I will count my blessings that it doesn’t happen on the Gulf Coast and keep vigilant for the Palmetto Bugs.