Well Hello!So now i'm going to tell you about red crab migration phenomenon.This phenomenon is include to a biological natural phenomenon because it tells the life cycle of this species.Maybe some of you don't know,so i will try to make this writes clear to read for you.
This phenomenon is most happen in Christmas Island in Australia.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.
The crabs will start their migration if there is enough time for them to
complete their downward migration, mate and develop eggs before the
next suitable spawning date.The first action that occurs is movement of
crabs to the sea. The largest mass movement of crabs takes place in this
first downward migration. Males farthest inland start this movement and
are progressively joined by more and more crabs (both males and
females) as the movement progresses toward the sea.When the crabs arrive
at the shoreline, they dip in the sea to replenish body moisture and
salts.
The male and female crabs then move back on to the shore terraces
where the males dig burrows for mating. Mating takes place and then the
males again dip in the sea and then they will start their return
migration.Before the turn of the high tide and just before dawn the
females will again move to the waterline and around the turn of the tide
they will drop their eggs into the sea. After they have jettisoned
their eggs the females commence their return migration.All phases of the
crabs' breeding migration involve colossal numbers of crabs and usually
occur all over the island.
If the rains continue, there is usually a
second, and sometimes even a third, smaller, downward migration by crabs
that did not join in the first migration. When this happens it is
possible to see crabs on return journeys mingling with the crabs on
their downward migration. It can become confusing for all concerned! I'm so sorry that i can not be more explicit about the timing of the start
of the red crab migrations, but the weather as you know cannot be
accurately predicted. The best advice i can give is to be at Christmas
Island during the last quarter of the moon in either November or
December for the best chance of seeing something interesting happening
in the annual red crab migration. If you are able to arrive earlier and
to stay longer the more parts of the migration sequence you will be able
to experience.
I think that is all that i can share about this passage.Thx
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