Thoughts on Vitamin D

[fraksocks]

So do we have definitive documentation that Es fight more or lead a less harmonious existence with eachother in the wild than PPs or other species?

[kuza]

There's an article about it earlier int he thread, yes. It doesn't say they fight "more" than other species, but it talks about compressus in general fighting a lot.

[boxcat]

There's an article about it earlier int he thread, yes. It doesn't say they fight "more" than other species, but it talks about compressus in general fighting a lot.

But not even that. Maybe it's my history of working with zoologists and reading field studies, but nothing in the article wodes posted made me raise my eyebrows and say, "Wow, C. compressus exhibits more fights than is expected of any wild animal population." Fights are natural, especially in the wild where the stakes are higher. The article didn't focus on the violent tendencies of C. compressus, in fact it was the second to last thing they mentioned (giving it only a few lines in an 8 page paper).

[kuza]

they specifically mention seeing it multiple times but only described 1 encounter.

[fraksocks]

That's my point we are assuming that because we are seeing some instances of "unexplained" aggression in captivity and there is anecdotal documentation of instances of things like shell fights in the wild that Es are "naturally more aggressive". Perhaps this is not the case and is not accurate as a general statement. I think that unless there have been careful comparative studies between wild populations (both within their same species and across species) that we are getting ahead of ourselves by making statements like that.

Obviously, ensuring that our crabs are provided with the proper nutrition and care needs is paramount. A crab that is nutrient difficient in one way or another is probably more likely to target an individual within the population that is otherwise vulnerable. There are just too many unknowns about the natural behavior of the crabs. It would serve all of us much better to really start collecting some comprehensive data on things like crabitat size, approx size/age of crabs, addition of new crabs or recent deaths, recent weather/storms (I've seen several posts about crabs acting differently right around a big storm so some behavioral issues could be weather related), type set up (lots of hiding places, mostly open space, etc), diet, etc, etc. Not just for those members having issues but for those not having any. By tracking this information over a longer term we can start to hopefully establish a pattern/understanding of what is causing the issues for those that have them but also why some people don't have them. Long term tracking is also important because it is believed that issues may develop at the onset of sexual maturity in males and this would be a way to "test" for that trend.

[kuza]

If you take the time to read through this thread and the "I hate my E's thread" you'll see a trend of E's being the aggressors for most people. Forget the documentation, we are the statistics.

[boxcat]

I agree 100% with fraksocks.

If you take the time to read through this thread and the "I hate my E's thread" you'll see a trend of E's being the aggressors for most people. Forget the documentation, we are the statistics.

There's also confirmation bias and the fact that no, not all parties have reported in. I know of a few crabbers who saw how to dissenting opinions were attacked on the E thread and chose to stay out of it. Unfortunately, that means our "sample" is not complete.


Edit: But again, we digress from the actual discussion here: The importance of vitamin D for hermit crabs. The E argument already has its own thread.

[fraksocks]

Fine yes there's a trend but it's far from clear if this their natural way of being or something caused by a condition (or multiple conditions) within captivity. If we made a more comprehensive study of the issue with documentation of the factors involved we might discover that we can make some simple changes that mitigate or make the Es natural tendencies more manageable/predictible. Right now most people are just shrugging their shoulders and saying "it's just Es" or "I hate my Es" what if there is a way for us to make their lives better and take some stress off of us. As an example we might discover that a sexully mature male needs X amount of territory at a minimum or can only be kept with females so knowing they sex of your crabs is very important if you intend to keep Es or we might discover that Es are more effected by changes in the barometric pressure or that they have very specific and mostly inflexible social structures than other crabs so adding new members to an established colony is inadvisable or needs to be done with greater care. Those are just a few examples. To be honest those are just guesses based off of what I've seen in the several threads discussing it. Personally, it's frustrating to me to see a community that I'm part of identify a problem and then say "Well there's just nothing we can do about it" or assume that it's unexplainable before taking the time to do a comprehensive survey or collection of the data to really see what they root cause is. Each member has one part of the picture we just need to put them together.

[fraksocks]

And getting back to the vitamin D issue I would love to see this included as part of a comprehensive survey. I think that there is strong anecdotal evidence to support that the crabs appreciate and see benefits from full spectrum lighting. I think too that it would be important to differentiate between supplemental Vitamin D and that provided through full spectrum lighting as, at least with humans, there is some evidence that supplemental vitamin D is not used in the same way by the body.

[kuza]

Fine yes there's a trend but it's far from clear if this their natural way of being or something caused by a condition (or multiple conditions) within captivity. If we made a more comprehensive study of the issue with documentation of the factors involved we might discover that we can make some simple changes that mitigate or make the Es natural tendencies more manageable/predictible. Right now most people are just shrugging their shoulders and saying "it's just Es" or "I hate my Es" what if there is a way for us to make their lives better and take some stress off of us. As an example we might discover that a sexully mature male needs X amount of territory at a minimum or can only be kept with females so knowing they sex of your crabs is very important if you intend to keep Es or we might discover that Es are more effected by changes in the barometric pressure or that they have very specific and mostly inflexible social structures than other crabs so adding new members to an established colony is inadvisable or needs to be done with greater care. Those are just a few examples. To be honest those are just guesses based off of what I've seen in the several threads discussing it. Personally, it's frustrating to me to see a community that I'm part of identify a problem and then say "Well there's just nothing we can do about it" or assume that it's unexplainable before taking the time to do a comprehensive survey or collection of the data to really see what they root cause is. Each member has one part of the picture we just need to put them together.

My aggressive E's came that way, which we discussed before. That's th only reason I dont' believe it's only condition related. It might help exasperate the issue, but I dont' think it's the main ingredient.

Sorry to go off topic here, but I thought from the first sentence in the first post was bringing the discussion here.

[boxcat]

My aggressive E's came that way, which we discussed before. That's th only reason I dont' believe it's only condition related. It might help exasperate the issue, but I dont' think it's the main ingredient.

Sorry to go off topic here, but I thought from the first sentence in the first post was bringing the discussion here.

Apologies if I was ambiguous about our point. Our point was that perhaps behavior and other observations of crabs in captivity (such as the shrinking jumbos I've mentioned a few times now) could be explained in part by vitamin D deficiency. Where that deficiency comes from (diet or lack of UVB) we are not sure, and as for how it manifests-- well maybe in part, as aggression.

[kuza]

And I'm all for helping figure it out, I'll have before and after pics of my crabs once they have been basking in UVB for a couple months, I think it might be too early to tell any major color variance or attitude changes.

[wodesorel]

As far as crabs fresh from the wild go, I'm sure that everyone here has noticed a propensity toward aggressiveness in their new crabs regardless of species.

My PPs stay aggressive for a few days. Once they've had access to shells and a few days of good food, they're peaches afterwards.

As far as I can tell, there's a trend toward aggressiveness in Es with overcrowding and lack of UVB, but not a definitive correlation, just based on my own readings here at the HCA with the many members who have Es, and the papers definitely support that (although I'll admit I still haven't read them in full and am working through them)

I was down to five crabs in a 55 gallon with a foot of substrate, how is that overcrowding?? And again, I've been supplementing with D powder from the beginning. (I just chose not to talk about it since it's never been a recommended item with hermit crabs since the safety ingredient cannot be confirmed in use with hermit crabs.)

I'm postulating, based on general feral animal and WC animal rules, that as competition for resources (including vitamin D), decreases, people will see a correlation in decrease of aggressive behavior.

This is not what your opening post stated at all. It only talked about deficiency of Vitamin D causing all the problems with Es.

Protein deficiencies are constantly cited as being likely sources for this behavior when it occurs on this forum, but maybe it's not protein (especially since it apparently happens even with keepers feeding a diet high in proteins), but another type of deficiency.

I have found it interesting that no matter how many times I offer the Es crab meat (the real stuff) or Alaskan Hermit's crab exo (any of the species she's carried, as I have a bit of all of them) - my Es will never touch the stuff, no matter how many times I offer it and how long I leave it. The PPs? Good luck with it lasting overnight! You would think with their penchant for eating others that the Es would want more crab material, but they ignore it. It has to be something species-specific that they're after if it is something diet related.

I feel that something that's done in a lab or on a field can't always be compared to what goes on in the tanks of hobbyists.

Very true. Captivity is way different then the wild, and only through trial and error can we learn what works and what doesn't in our own tanks. Just because they're a communal species in the wild doesn't mean they'll do okay with multiple others in captivity. It may very well be that the best combination is one male and one female, or a male and a small harem. (Several fish and reptiles are better kept like this in captivity, even though in the wild they're found in large quantities of mixed groups.) As far as care and environment, start with what we know about the are they are found in, and tweak it from there.

Maybe it's my history of working with zoologists and reading field studies, but nothing in the article wodes posted made me raise my eyebrows and say, "Wow, C. compressus exhibits more fights than is expected of any wild animal population." Fights are natural, especially in the wild where the stakes are higher. The article didn't focus on the violent tendencies of C. compressus, in fact it was the second to last thing they mentioned (giving it only a few lines in an 8 page paper).

No, but the papers out there on clypeatus and shells are about shell chains - where they line up in a rather neat little order and swap out. Not about them going after the shell of another crab one-on-one, and observed with multiple crabs on multiple occations! That to me is telling that there were no shell chains witnesses with the Es. It shows they're a little more violent and "me me me" and little less organized and "all for one" than PPs at least.

[Kat]

And I'm all for helping figure it out, I'll have before and after pics of my crabs once they have been basking in UVB for a couple months, I think it might be too early to tell any major color variance or attitude changes.

I'll be posting before and after of my straws as well; you can definitely tell changes now, but I want to wait until they are undeniable.

Wode, with all due respect, I'm not sure how you took my post as a personal attack, but from the way I'm reading your reply, you did. I'm sorry if you felt that way. I'll openly admit that I'm not nearly on the same level as the members who have dedicated their lives to scientific thought and research; I'm a teacher and a musician, so my specialty is a totally different area.

My main point continues to be that competition stems from lack of resources. In the wild, Es suffer from lots of deficiencies, but not vitamin D. In captivity, they exhibit the same behaviors, to a lesser extent, with "complete" care. Why is it such a leap to say that they are missing something, and that based on the arguments put forth, that is vitamin D?

Frak, if you have time to put the data together, I'd be more than happy to track any data you need with my own crabs. I'd love more hard data on hermit crabs, especially Es.

Take a deep breath, nothing should be personal here. We're talking about abstracts, not about specific crabs.

[fraksocks]

Kat yes I'd love to get a data collection/survey project started. After work today I plan to put out a "feeler" post to get some feedback on what infotthe community thinks should be included, how best to collect the info, etc.