Gecarcoidea natalis, known as the Christmas Island red crab, is notable for its bright red coloration, large population, and annual mass migration to the sea for breeding. They inhabit the dense forests of Christmas Island and play a crucial role as ecosystem engineers by recycling nutrients and aiding seed dispersal.

Gecarcoidea natalis, commonly known as the Christmas Island red crab, is native to Christmas Island and the nearby Cocos (Keeling) Islands, both located in the Indian Ocean. These islands are Australian external territories, situated about 1,550 kilometers northwest of the mainland of Australia.

The species primarily inhabits the rainforest environments of Christmas Island. The climate in this region is tropical, with a wet season from November to April and a dry season from May to October. The red crabs require a humid environment, which is provided by the dense canopy of the rainforest that helps maintain moisture levels in the soil and air.

Gecarcoidea natalis plays a crucial ecological role in its habitat by participating in nutrient cycling. The red crabs are primarily detritivores, feeding on leaf litter, fruits, and flowers that fall to the forest floor. Their feeding activities help in breaking down organic matter, enriching the soil, and facilitating nutrient uptake by plants. The crabs also contribute to seed dispersal and forest regeneration by carrying seeds and other plant material across the forest floor during their migrations.