Musical Shells

[catsittingstill]

Cassiodorus, the bigger of our two hermit crabs, swapped shells last night. He's been interested in other shells for some time, but most of the spare shells Kip and I had gotten for the crabs were too big (it's hard for a human to judge these things and we always erred on the side of too large). One shell met with enough approval that he swapped into it when we first got the crabs, but he hastily swapped back again.

This time Julian, the smaller of the two crabs, noticed what he was doing. She came over to investigate, and though he shoved her away from his old shell, he was also hurriedly trying out his new one, and while he was practicing to see if he could pull all his limbs inside the new one, she snuck around behind his back and quickly swapped into his old shell, leaving her old one behind in its place. She seemed to have no doubts about her new shell, hurrying away again after only the briefest session of feeler-patting and groping to see how big it was on the outside.

In the meantime, Cassiodorus is not completely happy with his new shell. He even swapped out into Julian's old one--but it was so small he couldn't even pull in far enough to get his eyestalks under cover. Kip and I watched this for a while, engaging in the human habit of empathizing with something that probably feels no emotion whatsover, and finally couldn't stand it anymore. When Cassiodorus swapped back into the large shell we took Julian's old shell away from him so he would quit agonizing over it.

The next time we go into Knoxville we'll take Julian's old shell with us so we can pick out a couple that are just a bit bigger and give Cassidodorus more choices.

Comments

[catsittingstill.livejournal.com]

They are terrestrial hermit crabs. We keep them in a 10-gallon aquarium with sand for them to dig in, and a big dish of water to help keep things humid because even terrestrial crabs need to keep damp.

I agree with you in general about more complex animals experiencing emotion. I have my doubts about hermit crabs because 1) I think we're talking about a brain the size of a pinhead and 2) most of the time my automatic human estimates of what they will do next based on what emotions I think they feel (based on their body language and immediate circumstances) are just way off. They never do what I expect. Thus my hypothesis that they don't experince emotion in the same way that humans do.

Cassiodorus still looks like he's sulking, crouched facing into the corner of the tank. But maybe he's only resting up to get the energy to look for a better shell.

[randwolf.livejournal.com]

They aren't mammals; most human intuitions about emotion are based on mammalian cues. Being warm-blooded creatures has a lot to do with the basics of mammalian emotions, which makes for a huge between humans and most species. To know if crabs experience emotion, we'd have to first have a species-independent definition of emotion, and we don't. This is a question from the big box of philosophical questions traditionally labeled "nature of the soul" (or, for philosophical materialists, "mind") and there's not much reliable knowledge there.