The commonly named Halloween Crabs are native to Central America. They are very common land crabs in the coastal lowland tropical rain forests of Costa Rica, and besides Halloween Crabs they are also known as Mouthless Crabs or Harlequin Land Crabs.

This crab digs burrows and lives in the forest at least some of its adult life.

Even though Gecarcinus Quadratus is a land living crab it must have access to water in order to keep its lungs wet, if they dry out then the crab will quickly die. Water is also needed for reproduction.

Halloween Crabs are quite attractive with a black carapace, orange legs, and purple claws. Because they are terrestrial and so colorful, in the wild, these nocturnal land crabs live in small burrows in the coastal jungles of Costa Rica. Halloween Crabs are most common near the coast because they must return to the ocean in order to reproduce. They range from the coast to about 0.4 miles (600 m) inland.

Halloween Crabs emerge at night to collect fallen leaves and seedlings, which they then drag back into their burrows to eat in safety. At the Harmony Hotel, these crabs are often seen in the gardens, hallways and especially on the path to the beach.