Millions of Red Crabs Cause Traffic Jams on Christmas Island

One of the largest animal migrations on the planet takes place now on Christmas Island, a Western Australian territory in the Indian Ocean south of Java, Indonesia. Millions of red crabs make the trek from the jungle to the ocean. It creates a spectacular display, as red color sweeps the island. However, the migration also causes traffic jams, as the red crabs swarm across roads and bridges, blocking the travel of cars

Red crabs migrate on Christmas Island to breed on the beach

Red crabs walking on a road on Christmas Island, Australia
Red crabs on Christmas Island, Australia | Parks Australia via Getty Images

The red crab migration on Christmas Island is an annual phenomenon, as detailed by the Daily Mail. The first rainfall of the rainy season, which happens either in October or November, typically triggers the migration. Red crabs migrate to breed. After heavy rains, the male crabs head “toward the beach, picking up females on the way.” Also, the timing of the migration is “determined by the phase of the moon with the crabs predicted to spawn on the 29th or 30th of this month.”

After breeding, each female red crab releases an incredible 100,000 eggs into the Indian Ocean over the course of five or six nights. A month later, the baby red crabs return to the beach and then migrate to the jungle on Christmas Island. However, most of the eggs that the female crabs hatch get eaten by other marine life, such as manta rays, fish, and giant whale sharks.

Red crab migration is the largest since 2005

Red crabs walking in a drain on Christmas Island, Australia
Red crabs on Christmas Island, Australia | Parks Australia via Getty Images

The annual red crab migration is always an amazing spectacle. However, in 2021, it’s even more impressive, for it’s the largest migration since 2005, according to Dr. Tanya Detto, an invasive species program coordinator at Christmas Island. An estimated 50 million red crabs will make the trek this year. The crabs journey across roads, bridges, fields, streams, and rocks — all so that they can breed and create new life.

Measures to keep the red crabs off the roads and aid them in their migration

Bridge for red crabs to aid them on their annual migration on Christmas Island, Australia
Red crabs on Christmas Island, Australia | Parks Australia via Getty Images

Dr. Detto and other wildlife specialists on Christmas Island take several measures to aid the migration of the red crabs and keep them off the roads. This includes constructing special crab bridges, as well as temporary barriers. She said, “It’s been really nice to see them being funneled away from the traffic and getting there safely.”

While experts can roughly predict the route that the red crabs take for their migration, it varies a little each year. Most of the red crabs survive the journey, but, unfortunately, some fall from the island’s cliffs, get “stuck climbing over three-story buildings,” or get hit by cars. 

Locals on Christmas Island rake the red crabs off the roads


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With the massive amount of red crabs crossing the roads, travel is difficult on some parts of the island, creating traffic jams. Some locals resort to moving the red crabs off of the roads with a rake to clear a path to drive. Also, the annual migration attracts tourists from all over the world. Wildlife experts encourage visitors to “park their cars and carefully walk among the sea of bright red crabs as they make their way to shore and amass on the rocks.”

The annual red crab migration on Christmas Island in Western Australia is an amazing natural phenomenon and demonstrates the extreme lengths that some species go to procreate. Would you make a harrowing trip from the jungle to the beach to unite with a loved one and make a baby? That would be romantic, wouldn’t it?