All my life I assumed hermit crabs deal with moving house the same way us humans do. When our living space gets a bit too cramped, we find a better-suited one, vacate the old one, and move. It's a fairly self-centered process and we rarely think about who ends up in our old space.
Well, I was wrong.
Biologists from Tufts University and the New England Aquarium recently published a paper in the journal, Behavioral Ecology, on the use of social networking by hermit crabs looking for new digs. They report that when a solitary hermit crab finds a housing upgrade, the overwhelming majority of the time, (s)he sits there by it and waits. Other 'waiters' soon congregate and the whole group begins to line up by size in what the authors call a 'vacancy chain.'
(You know there's video below the fold!)
If the newly discovered vacant home is too big for any of the waiting crabs, they entertain themselves by checking out the prospective homes around them. Crabs are seen grasping and piggy-backing other crab's shells in what appears to be claim-staking for the ensuing vacancy chain. Once an appropriately sized crab finds the group and decides to upgrade into the empty shell, these piggyback lines turn into the queue and the house swapping begins.
Not only is this an efficient use of space, it also increases the likelihood of finding a well-suited shell. Plus, it doesn't crowd up all the streets on the first of every month with moving vans and your friends are already right there to help you move your crap.
Here's the video:
I wonder what would happen is this were the new place for rent.
Check out the full paper here.
Interesting. My hermits (hairy hermits, Pagurus hirsutiusculus) don't do that. Usually, one comes upon an interesting shell and looks it over for a while, turning and lifting it, and inspecting the inside. If another hermit comes along, he/she makes threat motions until the other leaves.
After a time of thought, the hermit will change over. As often as not, the new shell isn't satisfactory, and he/she changes back in a few seconds. Not until the remaining shell has been abandoned, do any others dare to check it out.
This social behaviour may be species-specific.
On the other hand, having read the entire paper, it may be dependent on the population density and/or the availability of shells. My group runs from 12 to 24 hermits in a small tank (quite crowded), and they have been amply provided with a variety of shells.
I think I'm going to try limiting their shell choices, to see what happens.
Be sure to let us know what happens!
It's more similar to house-buying in England: if you want to sell your house to buy another, you need to have both buyer (for your old house) and seller (for the new house) in place to proceed. The same goes for your buyer and seller, unless the buyer is a first-time buyer or the seller is not buying a new house. Buyers and sellers, then, form a chain. Only when all the documents are in place the sales proceed, all in the same day. A lot like the hermits...
Great post Julia!
I guess the truth to try and see what happens
trickle down economics... or good old hand-me-downs with simplings
yu and respect It's more similar to house-buying in England: if you want to sell your house to buy another, you need to have both buyer (for your old house) and seller (for the new house) in place to proceed. The same goes for your buyer and seller, unless the buyer is a first-time buyer or the seller is not buying a new house. Buyers and sellers, then, form a chain. Only when all the documents are in place the sales proceed, all in the same day. A lot like the hermits...thanks
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