Christmas Island red crab

The Christmas Island red crab (Gecarcoidea natalis) is a species of land crab that is endemic to Christmas Island and Cocos (Keeling) Islands in the Indian Ocean. Although restricted to a relatively small area, an estimated 43.7 million adult red crabs once lived on Christmas Island alone, but the accidental introduction of the yellow crazy ant is believed to have reduced the population by about a third. Christmas Island red crabs make an annual mass migration to the sea to lay their eggs in the ocean. As of 2020 the red crab had not been assessed by the International Union for Conservation of Nature and it was not listed on their Red List. During the annual mass migration to the sea for spawning, millions of crabs emerge at the same time, thickly carpeting the ground. Authorities institute road closures and detours as necessary.