Ok. This is slightly off-topic because the coconut crab is not indigenous to our waters, but it is so fascinating that I felt compelled to write about it. These monster crabs start life as ocean plankton. They reach a certain size at which time they drop to the seabottom just like many other crab. We have seen this behaviour on the back deck of the Explorer in which tiny little larvae washed onto the swim grid and literally transformed into tiny little crabs by the next morning. In common with other hermit crabs, they find a shell on the bottom and call it home. Eventually they leave the ocean and settle on dry land, changing their shells as they grow larger. According to Wikipedia, young coconut crabs that cannot find a seashell of the right size often use broken coconut pieces. Because of the monster size of these crabs, they finally outgrow their shells and develop a hardened carapace. Photo above is not retouched or photoshopped, they really get this big!! And can live up to 50 years.
Captain Mike