Million Red Crabs Cross the Road to Sea in Christmas Island

Between October and December each year, mature red crabs begin a fascinating exodus to the coast from the forest to breed and reproduce. The rains offer wet conditions for the walk to commence; however, the period of the exodus breeding series is connected to the moon’s phases also. Female red crabs are set loose in the sea exactly when the high tide turns, in the final lunar quarter.

The initial wave of the descending exodus is led by males and as they advance the females join them. When males come to the shore, they dig burrows. The females join them and they mate. Males dive in the ocean again prior to going back inland. The females form eggs three days after mating and stay in the wet burrows for between 12 to 13 days as they grow.

The eggs which the females release hatch instantly when exposed to the sea water and clouds of babyish larvae spin close to the shore prior to being washed to sea by tides and waves.

After around one month in the ocean and developing through numerous larval phases, the larvae have grown into creatures named megalopae which are similar to prawns. Megalopae converge in pools near the shore for one day or two, prior to transforming into baby crabs and exiting the water.

More info: Parks Australia


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