Millions of red crabs have begun their annual mass migration across Christmas Island, an Australian territory in the Indian Ocean, transforming roads and landscapes into a vast crimson carpet as they head to the sea for breeding.
This colossal natural event sees an estimated 100 million of the island’s endemic red crabs emerge from their forest burrows following the first summer rains of the Southern Hemisphere. Their destination is the Indian Ocean coastline, a journey critical for the species’ survival.
Locals, who number just 1,200 on the remote island, actively participate in guiding the crustacean columns, often clearing pathways to ensure the crabs’ safe passage. The slow-moving masses are visible in early mornings and late afternoons as they navigate roads and gardens.
Alexia McAulay, the Christmas Island National Park manager, noted the unique perspective of residents. “Some people might think it’s a nuisance, but mostly we think it’s a privilege to experience this,” she stated.
Upon reaching the shoreline, male crabs excavate burrows for mating. Female crabs then spend approximately two weeks laying and incubating their eggs. These eggs are anticipated to be released into the ocean during the highest tides around November 14 or 15, aligning with the lunar cycle’s last quarter.
The newly hatched crab larvae will drift in the ocean currents for about a month. They eventually return to Christmas Island as tiny juvenile crabs, each roughly half the size of a human fingernail.
Clearing paths for these minuscule returnees requires a different approach. McAulay explained, “We can’t rake them because they’ll get crushed. So instead of rakes, we use leaf blowers.”