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Blog PostChristmas IslandIslandsWestern Australia

Christmas Islands Red Crab Migration – 100 Million strong

By November 23, 2022August 17th, 2023No Comments
Out of the rainforest and heading for the beach.


One hundred million Red Crabs, all single-minded in their desire to reach the ocean. To play their part in the cycle of life.

Ending an epic journey by releasing thousands of eggs with a shimmy and a shake.

This is the Christmas Island Red Crab migration,  one of the natural world’s greatest wonders and life’s great experiences!

Christmas Islands Red Crabs / Gecarcoidea Natalis are land crabs, a species endemic to Christmas Island.

They live in holes all over the island’s rainforested areas; they are the island’s constant gardeners.

Despite this, an epic movement of tiny creatures occurs once a year at the onset of the first major rains of the new wet season.

Millions of crabs on mass retreat to the ocean to mate and spawn a new era.

Single-minded in their desire to migrate, all obstacles are walked over or around.


Christmas Island is the very tip of an extinct volcano. Situated on the edge of the Java trench, it rises abruptly out of the ocean.

A difficult journey awaits the millions of crabs that inhabit the island. All are driven by instinct to meet the timetable of their migratory clocks.

The migration is an epic journey of persistence and doggedness. It is overcoming the trials of life to fulfil commitments to ensure the next generation.

Heavy rainfall coaxes the crabs out of their shady niches and dens.

Seemingly overnight, the island turns red with red crabs, triggering a movement akin to a floating magic red carpet.

Huge numbers of crabs close roads while an army of leaf-rake-wielding volunteers get to work. All are as single-minded in giving the crabs safe passage as the crabs are in getting to the ocean.

Roads get closed all over the island.

Crabs get right of the way.

Signs inform what’s open & closed.

Major roads around the island are edged with protective barricades keeping the red crabs off the streets.

Crabs are funnelled along these thoroughfares into under-road tunnels and uniquely designed crab bridges.

A developed plan to ensure the red crabs arrive safely. At the same time, they are keeping the island from a complete standstill.

Emerging from the rainforest.

Barricades Funnell crabs towards safe passage & off roads.

Christmas Island Crab Bridge and Red Crabs are incredible climbers.

Centred around the need to breed,  these crabs require salt water to reproduce.

Hence the once-a-year trek to the beach from the rainforest. The entire migration lasts three months.

The phase of the moon determines the exact timing and speed of the migration.

Spawning occurs pre-dawn on a receding high tide during the moon’s last quarter.

Red Crabs know precisely when to leave their rainforest homes to coincide with this lunar date.

Rain triggers migration; everything synced with the lunar cycle.

Males begin the migration. Their job is to get to the beach and start digging burrows,  awaiting the arrival of the females.

A male Red Crab feverishly works on completing his burrow.


Arriving females descend into the burrows with the males to commence mating. Once completed, the males emerge,

returning to their rainforest homes.

Females continue to occupy the burrow, nurturing their clutch of eggs until the moon and tides are opportune.

Scaling a wall to get to the ocean.

Female with her clutch of eggs

A female loaded with eggs eyes the ocean.

Emerging on their chosen mornings, females will spawn their eggs into the ocean in a pre-dawn spectacle.

Racing to the water’s edge with raised front pinchers. Timed with an outgoing wave in a little Red Crab dance,

all eggs are released into the ocean.

Spawning of eggs into the ocean.

Pre-dawn congregation.

A pair of females spawn their eggs together.

Once finished, females return to the rainforest. Their clutch of eggs hatches promptly, once in the sea.

They are now at the mercy of the ocean, its currents, tides and predators.

Baby crabs emerge from the ocean in 4-6 weeks and begin their first migration back to the rainforest.

Drumsite, Flying Fish Cove and Ethel Beach are fantastic places to view the crabs during migration.

Crabs will be everywhere and easily spotted; however, these are great locations to see them in the most substantial numbers.

Flying Fish Cove is a great location to view the crabs.


The migration is an enthralling part of  Christmas Island’s DNA. The sound will stick in my mind most, millions of tapping little feet.

An equal amount of humans could never move in such an orderly way to achieve a common goal without fighting.

Part of the island’s fibre and its identity, these crabs are loved by locals and visitors alike.

Who all acknowledge their importance in the more excellent Christmas Island picture.

Naturalist Sir David Attenborough described it as one of his greatest TV moments, a truly breathtaking sight.

The mob from WeXploreTravel.


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