Crustacean Invasion: 50M Migrating Cannibal Crabs Cause Traffic on Australian Island

Red crabs are causing traffic issues on Christmas Island in Australia as an estimated 50 million of the crustaceans are making their customary fall migration from the island’s inland to the coast.

The crabs can be rather disruptive during migration, which typically occurs in October and November, as the hordes of the species inevitably make their way through roads and block traffic, as is the case currently, according to Parks Australia. The crabs can sometimes migrate as late as December or January, the agency notes.

“With red crab migration in full swing on Christmas Island, the crabs are turning up everywhere, including at the door of an office block,” Parks Australia tweeted on November 15.

“Our staff have been out managing traffic, raking crabs off roads and providing updates to the community on road closures,” the tweet continued.

It is estimated some 50 million crabs make the annual voyage, beginning with the male members of the species, according to the Sun. Females then follow suit.

One can see up to 1000 crabs in one square meter of rock or beach, per the Sun.

Though they eat “fallen leaves, fruits, flowers and seedlings,” they will “eat other dead crabs,” according to Parks Australia.

Female crabs carry up to 100,000 eggs and may release the eggs into the ocean on five to six consecutive nights, according to the agency.

The annual spectacle is a significant tourist attraction for the island, says National park acting manager Bianca Priest.

“Over the years visitors have travelled from every corner of the world to witness this wildlife phenomenon,” as documented by the Sun. 

She added that even famous naturalist David Attenborough had documented the crabs in his extensive coverage of Life on Earth. 

“World-renowned naturalist Sir David Attenborough described the red crab migration as ‘like a great scarlet curtain moving down the cliffs and rocks towards the sea’ and considered filming the spectacle as one of his 10 greatest TV moments,” Priest stated.