Hanging "Shell Shops"

[DragonsFly]

For years now, I've had my "shell shops" (baskets full of empty shells) hanging; suspended from zip tie "chains" from the top of the tank (they hang next to climbing branches so that the crabs can get to and in them). This keeps the shells from being buried as crabs dig and overturn the substrate, and also keeps them at least a little cleaner (they still get some substrate in/on them over time, as crabs bring it up with them and then get it on the shells). For convenience of the human, it is definitely good; and it also provides more different levels, shady spots underneath, and more "cover" for crabs to feel less exposed.

However, I can't help thinking that it is a bit unnatural to the crabs, to basically find shells "up in the trees" instead of down "on the beach." Further, since we've just had a crisis that may have been shell-related, I wonder if having the shells up where a crab has to climb for them might not be a problem, say, if a crab is weak for some reason? Although, if the crab is weak, it would seem less likely that that same weak crab would then go to the effort of attacking another crab for THEIR shell?

Maybe a crab is lazy, though, or maybe it just didn't occur to it to look for a shell up there, so it thought there were no other shells available other than the one another crab is wearing? (They ought to "know" that that is where the shells are, as they have been there for years, but I have no idea how their memories work after a molt; maybe they would have to re-learn that every time through exploring the tank again?) As you can see, I'm still trying to think it all through.

Anyway, I'm just wondering if others have any thoughts about the advantages and disadvantages (TO THE CRABS) of having hanging shell shops, versus having the shells on the substrate OR having the shell shop itself down near or on the substrate (I did have the shell shop basket sitting on some rocks right on the substrate back when we had the 35g; the crabs still had to climb up the side of the basket to get to the shells, but not as far as they have to climb to get to the "shops" in the 90g now).

[landlubber]

Those are some interesting thoughts. Personally I put everything a crab "needs" within easy reach, on the substrate for the very reason you mentioned-I want pre-molt crabs to save their energy for molting-and not use it to go and get food, or water or shells (even though it can be irritatingly inconvenient for ME to do it this way). Also, as you said, my thoughts were shells were found near the beach on the sand in crab's natural environment that is what I would try and duplicate.

I do not know how memory works for these guys, and I'm not sure they "remember" what shells are available, whether they are new or not.....I can just move them around and they'll check these shells out all over again as if they've never seen a one of them before. It may be they use several environmental cues in memory, so if one of the cues is gone or different the "message" (food here, shells here, water here) may be different.......It is possible that with shells out of sight and out of mind that if a crab saw another crab with a desirable shell he could challenge him for it. All Scavengers are opportunists to the highest degree! I just think your thought process on this seems very reasonable....

[CallaLily]

Many crabbers have used elevated shell shops for years, myself included. The crabs easily find and use them. In my memory, there hasn't ever been a reason posted here to think they cause any issues. I do keep some on the substrate too but they do seem to mostly swap out with those in the baskets. Probably due to them being cleaner and the ones on the sub getting buried often.

I think they definitely remember where to look. Someone on here mentioned that they noticed even after moving something in the tank, their crabs would head for that old "escape route" for a time after it was no longer there. I don't remember who but hopefully they'll chime in.

[megmaholm]

My shell shops are both elevated without any issues. The only time I ever have shells on the substrate level is if I have a new crab - I plop a couple near them so they don't have to go looking. Even that isn't really necessary, it just makes me feel better.

I'm not sure if they keep track of what shells are available, but they always show an interest if I rearrange the shells, clean them, add new ones, etc. They definitely can remember where stuff is.

[landlubber]

There are certainly many pros to having them elevated. Lots of people do it without any issues. Lots of crabbers and crabbies are totally satisfied with the arrangement. I consider having them all on the floor to be a personal preference for me. I've always done it this way for the reasoning I mentioned and never really felt a strong reason to change. I also like the way it looks, actually.

I also agree that they know where to look if shells are kept in a consistent place. I do think they make a mental map of their crabitat the way they do in their natural habitat. But they act so strange about shells......from a biological point of view they are probably hardwired to think of shells as an extremely important resource. Without proper shells crabs are not only more susceptible to predation but also it in affects how they fast and how properly they grow, which effects agian defense against predation but also reproduction (larger crabs may more likely to get to pass on their genetics). So basically shells are a BIG BIG BIG deal instinctually to our crabs-it's more than somewhere to rest their soft tushies-it's also vital to multiple aspects of their survival.

So I don't know if they remember individual shells, because they appear not to. Which is hard to explain.

As a former dog trainer I know for something to mean something (for a trainer to construct meaning for a dog where none previously existed) a dog needs cues. The cue tells the dog to do something-it gets associated with an action. For example-the word SIT is a verbal cue the trainer uses which tells the dog to put his butt on the floor. However, for the dog, everything in the environment where it first learns the word SIT gets associated with that action. So for example, if you teach the word SIT while standing in front of the dog, in the living room those stimuli get associated with the word SIT so that if you say the word SIT while seated at your dining room chair in the kitchen the dog may look at you confused, because the dog has not generalized the verbal cue SIT to mean the same thing in the kitchen with you sitting at the dining room table as it did in the living room with you standing in front of him. A good trainer re-trains the word SIT to mean a multitude of things (how long to sit, where to sit, what needs to happen before the sit can stop) and to focus on the verbal cue which is what is constant. Otherwise reinforcement history gets mixed (but I digress now). Cues are used in learning all the time with all kinds of animals, including people. For example you grab your dog's leash without saying or word, or grab your purse those are cues to your dog that something is about to happen even though you did not purposely associated those cues with those actions.

And what does this have to do with crabs? Well, I was wondering if crabs learn what things mean the same way. For example-I clean up the tank and take out shells and rinse them off. I put them back in the tank-but now that shells are put back in a new place. Maybe the crabs see those shells as new because the environmental cue (the shell is not sitting by the water bowl where it was previously where the crab checked it out and found it lacking) is different, so their understanding of whether or not they "know" the shell is different because it doesn't match up with the memory of the shell (where it was in the tank).

I don't know, but sometimes I like to try and think about what a crab might think, ya know?

[rainbow_crab]

I use corner shower caddies in my tanks for shell shops and moss pits. Considering purple pincers in the wild often climb trees for food, safety, and I'm sure other reasons I don't know of, my crabs prefer to be elevated over just being on the substrate. My crabs are often just hanging out or sleeping in the shower caddies, or branches of cholla. My es prefer to hide in the coconuts and half logs on the surface more often then being up like the pps. But they also check out the shell shops from time to time. I have always kept my shells in shower caddies elevated from the substrate. It's never been an issue for the crabs. I have had she'll fights but I don't think it's because a crab was to lazy to go find a shell, I think crabs are keen to see a shell they want and they will fight for what they think is best. Shells are one of the most important things in crabs lives so I feel they will seek them out regardless of location. I also like to consider in the wild they do not have such easy access to spare shells, and haven't been catered to find shells to fit them in just their size. Idk never had issues with elevated shells, the crabs always seems to know where the shells are even after a molt.

[DragonsFly]

Thanks, I appreciate the thoughts very much. I'm going to think about a redesign, while almost everybody is down for the winter.

Anybody else have any further thoughts about the relative merits of hanging "shell shops" vs. shells-on-the-substrate, or other ideas for making them easily accessible but less likely to be buried/full of substrate all the time?

[piccolo41099]

In 10 years of crabbing, I have always had my shells in a hanging shell shop. I have never had any issues. They do tend to kick shells out of the shop from time to time, but no one ever seems to pay much attention to the shells on the sand. I also feel that because I have so many extra shells offered they would just take up too much space on the sand.