Larvae Grow To Baby Crabs In The Sea
The eggs released by the females hatch immediately on contact with the sea water and clouds of young larvae swirl near the shore before being washed out to sea by waves and tides. Millions of the larvae are eaten by fish and plankton feeders such as Manta Rays and the enormous Whale Sharks which visit Christmas Island waters during the crab spawning season.
After about a month in the ocean, and after growing through several larval stages, the surviving larvae have developed into prawn-like animals called megalopae. The megalopae gather in pools close to the shore for 1-2 days before changing into young crabs and leaving the water.
Although only 5mm across, the baby crabs begin their march inland, taking about 9 days to reach the plateau. Here they seem to disappear and are rarely seen, living in rocky outcrops and under fallen tree branches and debris on the forest floor for the first three years of their life.
In many years, very few or no baby crabs emerge from the sea, but the occasional very successful year (perhaps only one or two every ten years) is enough to maintain the Red Crab population to a high level.