Wednesday, December 06, 2017

Wise old eyes

Every week or so, I remove all my hermit crabs from the aquarium while it is being cleaned. And while they're milling about in the holding basin, I count them. I brought 19 with me from the mainland two years ago; there are 19 today. The smaller ones may or may not survive the first few months; it's a risky time, with all the molts and other growing pains. New babies arrive; some grow up. But the larger ones just keep trundling along, occasionally switching into larger shells.

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.

"Waves, Hi!"

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,

*Smarter than some humans I know.**
** At least, as far as food choices go.


  1. They really are quite photogenic as well!

  2. Ol' Fuzzy looks wise indeed. Quite amazing a crustacean can learn food aversion. For sure smarter than many humans!


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