Some species of hermit crabs can live up to 30 years. How old are my big grainyhand hermits? I don't know; they're not telling.
But they have wise eyes.
|Ol' Fuzzy, at the front of the tank, checking me out. On red Turkish towel.|
These are smart beasties.*
The common intertidal hermit crab Pagurus granosimanus learns in one or two trials to reject an attractive, novel food (beef) when illness is induced ... Food aversion learning has never before been reported in a crustacean. (Wight, Keith, et al. “Food Aversion Learning by the Hermit Crab Pagurus Granosimanus.” Biological Bulletin, vol. 178, no. 3, 1990, pp. 205–209. JSTOR, JSTOR, www.jstor.org/stable/1541820.)
*Smarter than some humans I know.**
** At least, as far as food choices go.