Halloween crabs (Gecarcinus quadratus) are a nocturnal crab native to the rainforests and mangroves of Central and South America. They are considered ecosystem engineers, because their diet is specialized to certain plants and seeds, which impacts which other plants get to grow. This subsequently affects which plants get to grow in their environment!

Fact contributed by Christofer Brothers. Sketch contributed by Isabelle McDonald.

[Edited by Isabelle McDonald]

Sources:

E. Griffiths, M., A. Mohammad, B., & Vega, A. (2004). Dry season distribution of land crabs, Gecarcinus quadratus (Crustacea: Gecarcinidae), in Corcovado National Park, Costa Rica. Revista de Biología Tropical, 55(1). https://doi.org/10.15517/rbt.v55i1.6073