Watch Orderly Hermit Crabs Line Up Biggest To Smallest, Swap Shells In ‘Conga Line’
Even hermit crabs, it turns out, aren’t safe from a housing crisis.
In the above clip from the BBC show, “Life Story,” several hermit crabs on a small Caribbean island off the coast of Belize are shown in their quest for suitable shelter, which involves lining up according to size and swapping shells in an orderly fashion.
Hermit crabs rely on shells (and flotsam, in some cases) to protect their soft abdomens from predators and the elements. They are always on the lookout for shells that might better suit their size and situation since, as the video states, “To be left without a shell is a death sentence.”
Amazingly, the crabs have developed this very cooperative, if self-serving, way of swapping shells — a sociological behavior scientists call a “vacancy chain.” Mark Laidre, then a post-doctoral fellow at the University of California, Berkeley, published a 2012 study that found that hermit crabs congregate around a smaller hermit crab, form a “conga line” smallest to largest, and then take turns moving into a larger shell.