Crabs committing suicide

[Christa]

Hi everyone,

This is something I've observed over the years about my hermies that I thought I'd throw out there --

You know how in Autumn in colder climates, crickets are found laying on the sidewalk, struggling, with their legs in the air? They are obviously dying, but when you try to right them again, they immediately flip back over. It is like they are trying to die.

I have had a few hermit crabs do the same thing. No matter what I do to keep them right-side-up, they always managed to flip themselves. In a matter of days I find they have died. It makes me wonder if they experience some sort of equilibrium (sp?) problem or perhaps it is something else altogether.

Any thoughts?

Christa

[Guest]

Well.. lil research boffin that I am might be able to explain this ... bear with me... what species are we talking about.. I know with Nar it was her Straw.. but if we are talking about this mainly being a crab whose habitat is on or south of the equator then I might be able to help...

on the equator temps remain constant pretty much with the seasons being dominated by storm activity.. so during certain parts its is say more humid than others.. for our lil freinds that come from the southern parts.. we should really remember one important thing.. IT IS SUMMER there..

constant high temps and constant high humididty due to tropical storms... so here in winter.. even tho we try to maintain a constant temp we might also be throwing their in clocks off kilter... the PP's are prolly more suited to the constant temps.. BUT i have noticed that my E's are craving HEAT... my Ruggers arent so bothered.. sometimes they come and bask.. but here in lies the problem... with a mixed tank how do we help them maitain it without throwing the whole colony off... do we simply by observation note which ones should be in the summer clims or do we boost our temps and humidity and see how the PP's and Ruggers act ... me.. im going to do the latter... if the PP's and Ruggers remain calm.. then I shall leave it.. I think they are abit more hardier than they those that need this seasonal thing...

anywho.. as per.. more observation and research is needed.. but so far.. i do think I might be on the right track... we might have it all wrong about mixing species... so when i get my tank heat boosted and humididty boosted i'll let you all know the results.. but only time will tell...It might just be a something else but one nevers knows till we hunt it out..

=/

[Christa]

I think the first time I noticed this behavior I was a teenager and there was nothing available in the US at that time except for purple pincher crabs. So I do not think it is a species-related thing. I should have mentioned something about that in my first post -- oops! I guess I should say for the record that when I note something I've seen over the years it almost always relates to PPs (and rarely, E's). Until mid-2002 there were no other species to be found here in Alexandria, VA.

Since I've owned exotics, let's see.... I've seen indos and cavipes do this. So that's a total of four species -- the ruggies and straws I have haven't done it *yet.* The E's seem to have a better track record of not insisting that they stay upside down. They seem to "snap out of it" after a couple times of being righted, if they do at all. It may be that all the species will do this if they are terminally ill.

Here are a few more observations:

It can happen at any time of the year. Unlike the crickets I mentioned, it doesn't happen only during season changes.

It most often happens after a molter has hardened up and appears to be intact, but is listless and not the typical active, happy-to-be-new molter that you normally experience.

It is critical that the upside-down crab be completely isolated during this time. For some reason others are drawn to the upside-down crab and attempt to maim or eat it.

If I can recall anything else, I'll post it.

hc!
Christa

[Dawn]

Winston, as you might have heard in my topic posted a couple of nights ago is acting this way. He was hidden under the rock, shell-less, newly molted. I mean he looked like a pinky mouse he was so new. he wouldn't go into a shell for several hours. I moved him to the iso tank with three shells and he moved into a shell in about an hour but was shell-opening-up and still mighty pink. I didn't observe any damage to his backside but it's hard to see without a spot light and not wanting to stress him out by over lighting him just to see him well...I didn't do it.

I found him in the new shell and turned him so that the opening was pointed sideways so that he could sit up and eat his exo or clam up. This position I've seen all my guys in. No stress on newly molted limbs by having to lift the shell or anything...But by morning he was sitting shell-opening-up again. He's still sitting that way.

Now I'm worried. Should I be? His coloring is coming back but he doesn't appear to have eaten much of his exo but this is typical of a new molter...I'll have to watch him closely.

The tank is at 72-74 degrees and humidity is 80% definately. He's in the darkness, parked in a plastic cabana between the sand and the moss. Water is next to him and exo is there. Food is on the other side of the tank.

[Dawn]

I'm wondering if this could be a crab version of swim bladder disorder...?

I checked Winny last night and he's right side up now and seems to be getting darker and more exo eatten or at least started to eat it. Whew. I'm starting to think I might be out of the wood now...

I know that one of the positions for molting is shell-opening-up so I'm wondering if these are moltings going bad or what. I don't think they have any difficulty breathing or existing upside down but this might be a symptom of the problem. I wish I'd stuck with biology!

[JediMasterThrash]

I haven't experienced this yet, but I'd like to respond to a couple of the posts about heat.

I've noted before that I think E's enjoy higher temps. Whenever I see E's in pet stores that have almost no water/humidity, but have hot overhead lights, the E's seem to still be very active and healthy. Actually I could go on for a long time about some observactions and theories related to this topic, but I'll save that for some other day.

Anyway, I've found that incandescent overhead lights are an excellent method for letting crabs regulate their own heat. In my tank, I have 2x25w moonglos. The substrate is 18 inches from the top, and I have both a second and third level (see the Action Platform crabarium posts). The temperature at the substrate level is about 72, while the temperature on the 3rd level is about 78. There's some higher-climbing items that can let them get within 4 inches of the light, where it's about 82.

What I've noticed is that my E's in patricular love to spend all their spare time up as close to the heat lights as they can be. They seem to really love the 80o temperatures. Many of the PPs and ruggies venture up there as well, but they usually spend their spare time on the bottom floor, hiding underneath something.

Also, starting with this tank, I've been providing a flourescent daylight that's on for 12 hours during the day (7am-7pm). It hasn't affected their activity negatively. In fact, some crabs seem to enjoy coming out under the light. Especially the E's, who I've said sit right under it at the top. Though E's are known to be more day-time crabs that PP's are (I've seen E's marketed as "exotic ecuadorian hermit crabs - active during the day!") But I also have PPs and ruggies that climb up around the top under the lights during the day too.

JMT.