Crab Crossing

Make way for the crabs! Around this time every year, as many as 100 million red crabs emerge from the rainforest on Christmas Island. That is a territory of Australia. The crustaceans scuttle across roads and sidewalks, headed for the beach where they mate.

The migration is one of the largest in number in the world. It takes place at the start of Christmas Island’s rainy season, usually in October or November. But the trip can be treacherous. About 1,700 people live on Christmas Island, and they can accidentally crush the crabs with their cars or even their feet.

To protect the crabs, workers temporarily block off roads. People on the island have also built tunnels along the crabs’ migratory routes so the creatures can travel safely beneath traffic. The island even has a special bridge the crabs can use to reach the beach. There, the female crabs release their eggs into the sea and then return to the rainforest.

The eggs hatch almost immediately. But the majority of the tiny offspring never make it out of the water. Many of them are gobbled up by huge whale sharks and other fish, says Chris Chartres. He is the manager of Christmas Island National Park.

Last year, however, millions of the baby crabs survived. Experts are hopeful this year’s migration will have similar luck. “Every year is different,” Chartres says. “But we’re excited to watch millions of red crabs continue this amazing journey.”

—Brooke Ross