It is known that the growth and egg production of marine and especially land hermit crab are affected by the weight of the shell occupied. (Bertness 1981b, Osorno et all. 1998)
Experiments have shown that hermit crabs in well-fitting shells can survive without food or water six times as long as those removed from their shells.
A new video on shells! We talk about good versus bad, measuring and where to buy! This is in two parts and viewable on the web. It was originally filmed via Periscope:
Our video on choosing the right shells