In addition, the part of the carapace covering the gills is inflated and equipped with blood vessels.

These organs extract oxygen from the air, analogous to the vertebrate lungs.

Adult land crabs are terrestrial, but visit the sea periodically, where they breed and their larvae develop.

Land crabs are tropical omnivores which sometimes cause considerable damage to crops.

The family contains these genera:[1] Mitochondrial genome sequencing indicates that members of the family (Gecarcoidia natalis and Cardisoma carnifex) are sister to the Sesarmidae.