The coconut crab (Birgus latro)

Mating occurs on dry land, but the females return to the edge of the sea to release their fertilized eggs, and then retreat back up the beach. The larvae that hatch are planktonic for 3–4 weeks, before settling to the sea floor, entering a gastropod shell and returning to dry land. Sexual maturity is reached after about 5 years, and the total lifespan may be over 60 years. In the 3–4 weeks that the larvae remain at sea, their chances of reaching another suitable location is enhanced if a floating life support system avails itself to them. Examples of the systems that provide such opportunities include floating logs and rafts of marine or terrestrial vegetation. Similarly, floating coconuts can be a very significant part of the crab's dispersal options.[4] Fossils of this crab date back to the Miocene.[5]