Christmas Island is home to two striking species of purple crab.

Gecarcoidea humei are not very common but can be found all over the island. Measuring up to 15 cm across, these crabs also live in Aceh, the Nicobar Islands, the Straits of Malacca and Thailand’s Andaman Coast.

Found across South East Asia and the western Pacific,Gecarcoidea lalandii​ can sometimes be seen in moist areas of Christmas Island’s coast and forest. Growing up to 16 cm, they are dark purple on top and cream underneath. They are similar to red crabs and have been spotted joining the annual red crab migration.