Fabricated shells lend hermit crabs a sense of identity
October 18, 2013
About this time two years ago, we looked at the efforts of Miles Lightwood and the Thingiverse community to 3D print shells for hermit crabs, but Tokyo-born artist Aki Inomata has been creating artificial shells for hermit crabs since 2009. Her most recent efforts are intricate and ornate, incorporating ideas on the theme of national identity through depictions of city skylines and vernacular architecture. The hermit crabs seem to like them too.
Strictly speaking, hermit crabs aren't crabs at all. Crabs belong in the Brachyura order of ten-footed crustaceans, whereas hermit crabs (though also ten-footed crustaceans) dwell alongside in the order Anomura. There are more than 1,000 species of hermit crab, but they all share a common trait. They have no shell of their own, and instead rely on empty gastropod shells for protection. Hermit crabs need to upgrade as they grow, their vacated shells often quickly snapped up by smaller individuals.
Where other attempts to create artificial homes for hermit crabs have been framed as an effort to address shell shortages (and there does appear to be evidence that shell availability is limiting factor for hermit crab populations), whether 3D printing can realistically hope to address the issue responsibly is perhaps debatable. Inomata makes no such claims, however. Her motivations, apparently, are wholly artistic.
The idea, she says, came from the change in ownership of the land on which the French Embassy in Japan is built: a peaceful, nearly invisible transaction between the two countries. "These kinds of things take place without our being aware of it," she writes. "On the other hand, similar events are not unrelated to us as individuals. For example, acquiring nationality, moving, and migration."
As with related projects, Inomata's shells are based on the gastropod shells to which hermit crabs' asymmetrical abdomens are so well adapted. CT scans were used to obtain detailed models of the internal shape of the shells. But on the outside, her more recent efforts have been embellished with details which speak to the theme of nationality. Designs include the New York skyline and a row of Low Countries windmills.
"Though the body of the hermit crab is the same, according to the shell it is wearing," Inomata writes. "Its appearance changes completely. It's as if they were asking, 'Who are you?'"
The hermit crabs don't seem to mind. Inomata has even observed hermit crabs choose her artificial shells over the real thing. You can see a hermit crab appropriate one of Inomata's designs in the video below.