This summer, I had the wonderful opportunity to visit St. Simon’s island in Georgia for a family vacation. Aside from the warm weather and the good company, the ocean was very warm and the low tides left deep, murky tidal pools perfect for hunting for plankton. Most mornings, while other people were out hunting for shells on the exposed sandbars, I waded in the silty water with a nylon stocking and a collecting jar to see what I could find. As a result, I caught many kinds of plankton, which I’ll post here over time, but I was most excited to observe crabs in each of the three larval parts of their lives.

Zoea


Naupilius

Megalopa
When the zoea and the naupilius forms of crustaceans were first discovered, it was generally assumed they were a whole new species, unrelated to anything known. Presumably it was not until someone observed a zoea in captivity for long enough to observe it turning into a crab that it was understood that these were actually part of a larger (and stranger) cycle of life that the crab went through, one that involved a portion of life spent drifting and struggling through the tides.

Kudos to the scientists who figured out this full pattern of the crab’s life, and for their willingness to see the mistakes made in their predecessors’ assumptions, not as a thing that needed to be defended, but as part of the purpose of science. To search and to discover and to reconsider always the things we never knew.