The Christmas Island red crab is 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,^[3] but the accidental introduction of the yellow crazy ant is believed to have killed about 10–15 million of these in recent years.^[4] Christmas Island red crabs make an annual mass migration to the sea to lay their eggs in the ocean.^[5] Although its population is under great assault by the ants,^[6] as of 2020 the red crab had not been assessed by the International Union for Conservation of Nature (IUCN) and it was not listed on their Red List.