Today there was an open house at a pre-Colombian archaeological dig site near our apartment. In Grand Case, these sites have some pottery, stone tools and bones, but the majority of the artifacts are shells, primarily conch and whelk. Scattered around the dig site, I noticed a few shells from the Giant African Land Snail, a recent arrival that definitely wasn’t around 1,000 years ago. I asked one of the archaeologists and he explained that during digs like this hermit crabs will walk out onto the dig site and exchange their shells for ancient ones, walking off with some of the artifacts! Apparently, this is not a huge problem, since some of these digs generate literally tons of shells.