Sometimes you're just in the right place at the right time ... Passing my aquarium on the way to start supper, I caught a glimpse of a naked hermit sheltered in the rosy seaweed. Supper forgotten.
|A hairy hermit, Pagurus hirsutiusculus, without the protective shell.|
Think about crabs. "True" crabs, they call them; the crabs you see scuttling sideways on the shore. They have a soft body encased in a hinged hard exoskeleton, the carapace on top, the abdomen beneath, sort of like a clamshell. When they grow and need to molt, they open this shell and back out, leaving the perfectly formed crab shape behind.
|Freshly-molted hermit, showing the upper carapace, two tiny grasping legs, and the front end of the soft abdomen.|
As a hermit (or crab) grows, the exoskeleton becomes a tight fit. It doesn't grow with the critter inside, so there comes a moment when he pulls himrself free and backs out, pulling the eyes down out of the eyestalks, the legs and pincers out of their chitinous coating; even the antennas are retracted, leaving the antenna shape behind, attached to the old body shell.
|Dried abandoned hairy hermit molt. (2010)|
|His colours are pale at this stage, and free of algae and grunge.|
My bad: trying to get a clear photo, I moved the seaweed and he fell off, down to the sand. Down where a crab lurked. I quickly rescued him, and set him to rest safely in a small bowl of water, then searched the tank for shells that looked about the right size for him. (Normally, he would do this when he was ready and able to run from the crab.)
|This one looks about right. Body hardened, abdomen protected. Ready to roll!|
I gave him some time to settle in, then returned him and the other shells to the tank. And he ran off, happily, to look for food. Needed a pick-me-up after all that work!