Red crabs are native to Christmas Island, Australia. The central plateau of Christmas Island is dominated by strands of rain forest. The island has a tropical climate and experiences both a wet season (December through April) and a dry season (May through November).

More than 120 million red crabs can be found on the rain forest floor of Christmas Island. Red crabs live alone in dirt burrows, or deep rock crevices. Crabs stay in the shade of their dwelling for most of the year. In October or November, when the wet season is about to return, crabs begin their migration to the shore. This timing coincides with the lunar cycle and the tides.

This video documents the first phase of the red crab migration, just before the start of the wet season. After spending a majority of the year in the forest, males journey to the shore. There, they dig burrows for the females, and then search for a mate. After mating, the female descends into the burrow, and the male returns to the forest.

animal migration
Noun

process where a community of animals leaves a habitat for part of the year or part of their lives, and moves to habitats that are more hospitable.

burrow
Noun

small hole or tunnel used for shelter.

crab
Noun

type of marine animal (crustacean) with a flat body, hard shell, and pincers.

lunar cycle
Noun

complete cycle of visible phases of the moon, approximately 29.5 days.

Noun

movement of a group of people or animals from one place to another.

Noun

large region that is higher than the surrounding area and relatively flat.

Noun

area of tall, mostly evergreen trees and a high amount of rainfall.

Noun

period of the year distinguished by special climatic conditions.

species
Noun

group of similar organisms that can reproduce with each other.

Noun

rise and fall of the ocean's waters, caused by the gravitational pull of the moon and sun.