From Sea to Tree: Saga of a Land Crab

Abstract

There are advantages to be gained when an animal abandons its ancestral home, the ocean, and advances across the littoral zone to the land. But along with the advantages come the inevitable problems. How a land crab, Gecarcinus lateralis, has solved its problems of life on land is the subject of this paper. Its use of dew as a source of moisture and of its burrow as a refuge from predators and a hostile environment; its ability to collect moisture from a damp substrate and conduct this moisture to its branchial chambers and its gills; its capacity to retain large amounts of water before ecdysis and to use this water to stretch its new soft exoskeleton and attain its proper shape after ecdysis are only a few of the crab's special adaptations for terrestrial life. Its feeding and reproductive behavior are equally adaptive, as is its propensity for tree-climbing when danger threatens–or at other times. During the past several decades, much interesting and important research has been done on G. lateralis, as well as on other land crabs–but much remains to be done. Land crabs are and will undoubtedly continue to be promising objects of scientific research.