Terrestrial Hermit Crabs Learning Social Tricks

An anonymous reader writes "When it comes to abandoned snail shells that hermit crabs expropriate as mobile homes, size matters, for room to grow, room for eggs, and protection from predators. UC Berkeley evolutionary biologist Mark Laidre found that terrestrial hermit crabs on the Pacific shore of Costa Rica congregate in aggressive swap meets where one crab is forced from a relatively large shell, whereupon the rest trade up (one loser and multiple winners, pretty good odds). The loser gets the smallest shell, which means likely doom. Laidre and his colleagues note that most hermit crabs live in the ocean, where there are usually enough abandoned shells to go around so most can live, well, hermit-like lives without much interaction with fellow crabs. Not so on land, at least in Costa Rica."

Crabs can also be turned into a computer

[girlinatrainingbra]

Crabs can also be used as the logic gates to compute certain functions. I kid you not! The Boston Globe [boston.com] had an article about some Japanese researchers who used crabs to design logic gates based on their motion on the beach.

Their swarm computing article (pdf link [complex-systems.com] in the journal Complex Systems) is rather interesting.

Memories

[jjp9999]

I used to go to Costa Rica during the winters when I was a kid, and I loved watching the hermit crabs. There are TONS of them there. All over the beaches. Crawling in the sand going down to the beach. I actually watched them hijacking shells from each other (although I'd play the good guy and get their shells back sometimes).

Had a pleasure to observe it in Costa Rica

[Anonymous Coward]

A stronger crab with a small damaged shell was trying to pry out a weaker one with new shell. He was probably weak from days of siege. I had to apply quite some force to tear them apart. After a brief isolation under toy buckets I set them free and the stronger crab jumped on his prey again, this time literally getting his foot in the door (they use the larger claw as a door).

There is a nice beach restaurant in Samara, Costa Rica, that I can recommend if you want to see them congregate in huge numbers, right on the sandy restaurant floor.

Re:Occupy Shells

[girlintraining]

Occupy doesn't work like that. They all get together and via a complex process of hand signals indicate what they like and don't like. Then they break up into smaller committees, and subcommittees, and breakaway groups, each with their own ideas of what ought to be done about a thing. After several months, nothing has been done, the fort has burned down, the police have kicked everyone out of the park, and the only thing they have in common is that they blame the government for their utter inability to organize. It's mostly the 18-25 crowd that populates the meetings... dreamers, not doers.

And like hermit crabs, they're also total dicks to each other -- which is why anyone inspired to go to one of these meetings quickly becomes uninspired by the amount of petty political infighting and bickering.