MakerBot have impressed us enough with their Mario-themed RC racers and self-replicating 3D printers, but now the collective is looking to save mother nature with Project Shellter. Turns out, there's a housing shortage in the oceans. Harvesting of shells has left many hermit crabs with no option but to take up residence in bottle caps and other debris they can squeeze their soft bodies into. MakerBot's Miles Lightwood, has decided to crowdsource designs for artificial shells that hermit crabs can live in. Right now Lightwood is testing different shapes, materials and colors, looking for the combination that the critters will find most attractive. The shells are not intended to be placed in the wild -- putting plastic into the sea wouldn't be very environmentally friendly. Instead, the artificial domiciles are meant for domestic use, reducing the number that must be harvested for pets. You can get updates on the project from its Facebook page (at the more coverage link) and submit your own designs to Thingiverse, just make sure to tag them "shellter."