Hermit crabs, as many a child could tell you, are not born with shells on their backs. They have to scavenge for suitable housing, which they usually find in a shell. But the current shell shortage has them turning to all kinds of alternatives that are less than ideal. Per Bre Pettis over on the Makerbot blog: "With a shell shortage, hermit crabs around the world are being forced to stick their butts into bottles, shotgun shells, and anything else they can find. This is not acceptable. As a community, we can reach out to this vulnerable species and offer our digital design skills and 3D printing capabilities and give hermit crabs another option: 3D printed shells."