Thoughts on Vitamin D

[boxcat]

My very first post in this topic. I've had my Es since Nov. 2009 - almost four years now. I have always supplemented Vitamin D.

My Es are not deficient.

My Es still have behavioral trouble.

Edit: I still have bad molts now and then.

So....?

Perhaps there is a difference in the bioavailability of certain vitamin D supplements? From what I've been reading there seem to be three common "sources" vitamin D can come in; maybe these three sources are all biotransformed differently? Heck, maybe there's a need for mixed dietary/UVB when they reach a certain age. Lots of possibilities!

And maybe it's not vitamin D. But to me, there still seems to be more to this.

Captive animals still feel tidal pull from the changes of the moon. They can still sense "real" sunlight through windows versus artificial lighting. They can still feel barometric changes. Being in a glass tank does not mean they are cut off from the rest of the world!

Yes, but even as far inland as some of our crabbers are? I don't disagree with them not being cut off from the rest of the world, but they are certainly (in most cases) cut off from their home. Do you have any articles about them sensing tidal pull and whatnot? I'd love to read more about it.

[wodesorel]

http://staff.washington.edu/aganse/euro ... tides.html

The moon pulls evenly everywhere on the Earth's surface - it's not just over the oceans! The oceans respond with "tides" because they are liquid and therefore more flexible, but the same force is exerted on land masses. An animal is going to feel that same force no matter if it's in the middle of a continent or on a boat in the middle of the ocean.

[Kat]

I'm going to start this off with saying that I did not read through all the replies yet. I am actually really busy right now what with speed-learning a new language and preparing for weeks of vacation and tank building, so I'll get to it when I can.

I'm not exaggerating when I say that I'm sure that UVB saved my straws' lives. In fact, once they have fully recovered, I'll be posting before and after pictures. My straws were nearly white after months in captivity with "near-perfect" care as far as we know, and after putting a UVB light in, they often bask underneath it and have been getting progressively darker with each molt. Nothing else has changed in the way I care for my crabs. If that's not a perfect example, I don't know what is.

I also don't have any aggression issues with my Es, although the lack of aggression predates my use of UVB, so there's that.

[Kat]

I know tensions are running a little high in this thread and considered not posting these additional thoughts, but I think they merit bringing it up.

When we talk about long-lived PPs, they are always ones that are fed with commercial food. I just got a PP from a lady that had the same PPs for 17 years, and the only food I got from her was the Tetra Hermit Crab Food, suggesting she was feeding commercial food. I'm betting Carol's crabs had access to true sunlight via screened windows as well; I know I open windows sometimes so my cats can look out and feel the air, and I'm thinking she did the same for her crabs. PPs do spend more time in shade, and possibly can live for a long time (but not for their natural lifespan) without UVB lights.

However, I'm quite confident in saying that Es and straws, based on my own observations, bobcat's references, and natural habitats, require UVB to live for anything approaching a normal lifespan. Without getting into aggression issues or shrinking exos, straws and Es live in very specific, sunbathed areas. They are observed as being more active during the day in captivity. It makes perfect sense to me that they would require more sunlight and therefore probably more UVB/D3 to stay healthy.

Just a few thoughts.

[Rocky]

If it is something we should consider, maybe we should start keeping track of behaviours versus who uses UVB lighting and who doesn't? Or maybe some people using it should stop for a time and some not using it should start for a time?
I just feel like the proof would be in the pudding, not papers, you know? I think we should experiment with our own little guys and see if anything changes. We certainly have enough people with Es and exotics to do so.

[kuza]

I do agree they may very well require UVB, I just don't agree that it's what causes E's to have aggressive tendencies. I'm going to go based on observation in the wild and it's a fact that they were seen multiple times in multiple areas, fighting. And also based on the fact that my aggressive E's were that way since day 1, they didn't become aggressive over a period of time. If anything they became more calm as time went on without UVB. And I got my E's when they first arrived at the store, so they were fresh out of the wild.

My E's ALWAYS went after fresh molters, I always had to take fresh molters out for baths because they were constantly picked on and mainly by my E's. Sometimes a straw would get involved by my straws are 100% less aggressive then my E's.

[Kat]

I definitely agree that Es go after fresh molters; that's happened to me once too. I'm not convinced that UVB is the *only* reason they would do that, but I'd think it's something to consider. Whether or not it's linked to aggressive behavior, it's reasonable to consider it and to also consider a connection between shrinking crabs and lack of D3.

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. The most violent crab I have had was a PP fresh from the wild. Competition for resources is very high, especially during shipping and sales, and I wouldn't be surprised that the ones who survive that are the ones who are the most aggressive. After a while, it starts to wear off, just like with any other feral animal.

Rocky: I certainly wouldn't be willing to turn the UVB off, but it's possible that we could start documenting. I'll respectfully disagree with you about holding more credence to application than scientific theory, although I completely agree that both are important. All that we can share right now are these observations and these studies. 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 have nothing to support my statement about straws except my own experience as stated above. Without long-term controlled scientific environments, I can't see a way to collect more hard data like these scientists are doing.

Thanks for contributing in a non-biased manner. I'm hoping we can continue this thread without making anything personal; there's a lot of experienced and knowledgeable crabbers participating.

[kuza]

There are no papers to support lack of UVB and aggressiveness in E's, where did you see that? And from my time on the forums, E's have been the #1 aggressor for people of all levels of crowding, so I also don't see how that has anything to do with it either. The trend, and you can do the math, is that E's are more aggressive period, no matter what the tank conditions.

We've heard from more people with aggressive E's than not. Go back through the relevant threads and count, don't just trust my math or observations. We've known for a long time that E's are the most aggressive species, so just because a few people haven't seen it, doesn't mean they need to start adding false information into the mix to justify it.

They have been witnessed may times in the wild being aggressive with each other, how much more proof do we need than that?

edit: I also agree PP's are next in line after E's from my own experience as well. They don't seem to be able to communicate well with exotics like how my blues and straws get along so well.

[Kat]

There are no papers to support lack of UVB and aggressiveness in E's, where did you see that? And from my time on the forums, E's have been the #1 aggressor for people of all levels of crowding, so I also don't see how that has anything to do with it either. The trend, and you can do the math, is that E's are more aggressive period, no matter what the tank conditions.

We've heard from more people with aggressive E's than not. Go back through the relevant threads and count, don't just trust my math or observations. We've known for a long time that E's are the most aggressive species, so just because a few people haven't seen it, doesn't mean they need to start adding false information into the mix to justify it.

They have been witnessed may times in the wild being aggressive with each other, how much more proof do we need than that?

Of course Es are more aggressive, but this is one case where I would argue that behavior in the wild doesn't have to match up to captive behavior. Many animals are more aggressive in the wild because there is a greater competition for resources; that doesn't mean that behavior has to transfer to captive situations. Yes, they are wild animals, but other wild-caught species (sorry, no source to back me up here except for experience with other feral/wild-caught animals and common sense) decrease or eliminate aggression once resources are satisfied. As per the initial post in this thread, it's quite possible that vitamin D (and space, as mentioned earlier) is to blame. For animals, especially WC animals, it all comes down to resources, and for hermits that means nutritional needs, shells, space, molting, and possibly mating.

As far as people who aren't seeing aggression in Es, I don't think it's fair to discount their opinion. You wouldn't discount the opinion of credible people who are not seeing problems in other areas, so why not here? My Es are generally non-aggressive. So are several other, much more experienced crabbers. If there's a chance that we can solve some of the aggression issues, it seems highly counterproductive to discount it out of hand. Also, I suspect that there are more reports of aggressive Es than non-aggressive Es just because those Es are the issue. You don't complain or ask for advice about things that are already working.

[Eugooglizer]

I haven't been very active in this thread so far--letting boxcat handle the replies pretty much on her own which really isn't fair considering I'm the one who has been theorizing about the role vitamin d3 plays in land hermit crabs--which we already know have very high calcium requirements--and the possible consequences of d3 deficiencies for a while now, making boxcat listen to all my ramblings until she started doing some in-depth research into the subject herself. Her very strong background in biology and chemistry along with currently being a student at one of the top vet schools in the country are just a few of the reasons I respect her input, ideas, and knowledge so much, and was extremely excited, as well as grateful that she was willing to sacrifice her own time, to collaborate with me on this subject and make it possible to propose our theories and provide access to some of the various published scientific studies relating to the subject to the hermit crab community. Our intent was definitely not "drama", personal attacks, and general negativity, but to provide fact-based information regarding a subject that thus far seems to have received very little attention in the LHC keeping community here in North America--the integral role d3 plays when it comes to calcium, and present some of our theories based on the not insignificant amount of research we've done on the subject in the hopes that a respectful discussion could be started where knowledge could be shared on both sides and at the very least encourage keepers who haven't already, to give the it some thought and a starting point for doing their own research in order to reach their own conclusions should they feel the topic merits it.

I think it's important to point out that UVB exposure and it's possible importance to the short and long-term health of LHCs in captivity is only one aspect of this topic, and by no means our sole focus. There have been quite a few questions asked and statements made that I feel I need to address and am in the process of wording my responses right now as well as finding the sources my information and opinions are based on in order to cite and provide links to anyone who may be interested in them.

[kuza]

I do agree there is a very high possibility they need UVB, it's the whole reason I made a UVB sundeck.

I just think these are 2 separate issues, the aggression and the crabs overall exoskeleton health.

I do not agree that providing enough shells, space, hides, or anything of that nature will prevent the aggression, since I have lots of space, more than enough shells (2 plus shell shops) and more climbing space then any tank I've ever seen. I had the same issues when I had a 29 gallon, with only 1 shell shop and lots more hides. The aggressive behavior was constant, and especially towards fresh molters.

[Kat]

I do agree there is a very high possibility they need UVB, it's the whole reason I made a UVB sundeck.

I just think these are 2 separate issues, the aggression and the crabs overall exoskeleton health.

I do not agree that providing enough shells, space, hides, or anything of that nature will prevent the aggression, since I have lots of space, more than enough shells (2 plus shell shops) and more climbing space then any tank I've ever seen. I had the same issues when I had a 29 gallon, with only 1 shell shop and lots more hides. The aggressive behavior was constant, and especially towards fresh molters.

I think we're talking about two different things here. I don't have an answer as how to completely eliminate aggression. I'd be interested to see if the aggressive behavior decreases the longer you have the sun-deck, though. 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. It's certainly true with all the other resources, and it's a given that all living things need vitamin D. It's an assumption, but a fair one, that certain species need more than others based on natural habitat and habits.

[Eugooglizer]

I do agree there is a very high possibility they need UVB, it's the whole reason I made a UVB sundeck.

I just think these are 2 separate issues, the aggression and the crabs overall exoskeleton health.

I do not agree that providing enough shells, space, hides, or anything of that nature will prevent the aggression, since I have lots of space, more than enough shells (2 plus shell shops) and more climbing space then any tank I've ever seen. I had the same issues when I had a 29 gallon, with only 1 shell shop and lots more hides. The aggressive behavior was constant, and especially towards fresh molters.

If you agree that there's a high possibility they require UVB for healthy exoskeletons, and you've noted in particular that instances of aggression seemed to be directed at fresh molters, is it not at least a possibility that the cannibalistic behavior could be due to a deficiency? 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. Freshly shed exos, as we know, are extremely valuable in vital nutrients and the actual body of a crab is likely to contain stores of fat-soluble vitamins as well. If this is the case, then plenty of space, hides, shells, etc. still wouldn't prevent the behavior from occurring--something that has already been noted by you and several others.

[kuza]

I would only agree if they didn't fight so much in the wild, where they clearly get enough sunlight.

[Rocky]

I would only agree if they didn't fight so much in the wild, where they clearly get enough sunlight.

That's the one thing that's throwing me off

And while you can't get much better than research, this feels like it'd be a bit different. 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. It can certainly help, but it still wouldn't really be the same. Just like with raising zoae in a lab and raising zoae yourself, they turned out to be drastically different.