Wednesday, May 18, 2011
Crab Migration:Yes, i said Crab Migration!
This amazingly strange migration occurs around the months of October - November where the Christmas Island Red Crabs move from the rainforest into the ocean to allow breeding. The males lead the first wave of the downward migration then 5-7 days later the females follow and at most time out number the males! It is said that the crabs replenish moisture by dipping in the sea, then the males retreat to the lower terraces to dig burrows.
The density of burrows is high (1-2 per square metre and fighting occurs between males for burrow possession. The females move to the terraces and mating occurs, usually in the privacy of the burrows that males have dug and fought for. As mating, and fighting, abates, males dip again and begin returning inland. They move quickly, reaching the plateau in only 1-2 days.The females produce eggs within 3 days of mating and remain in the moist burrows on the terraces for 12-13 days while they develop. The eggs are held in a brood pouch between their extended abdomen and thorax.
Fact: A single female can brood up to 100,000 eggs.
Posted by Murugi Njehia at 4:42 PM