Regrown limbs after a 2nd molt...

[Carrie]

Arwen lost 2 legs last winter, one in a molt and one later to an accident. (My hardwood floors now have rugs near anything the crabs might fall off of when I get them out!) The legs were both on the same side, and she eventually learned to walk using her little claw as an extra leg--and she recovered most of her agility, too. I was worried that her molt would be "lopsided," i.e., more difficult b/c she wouldn't be using muscles on that side of her body for the molt, since those legs were gone. She had no trouble molting, and her gel-limbs were replaced with new legs that were 3/4 the size of her original legs, fully functional yet a brighter red/orange color than the rest of her. She had to then learn how to walk w/ her two "new" legs again, having adapted to life w/o them. It was strange to see her walking around, obviously confused to have two legs where no legs had been before her molt!

I theorized that, with her next molt, her legs would be completely regrown--and now I realize that my theory wasn't quite right.

Now, after she's molted, her legs are normally colored again--not reddish-orange--but they're still just a little smaller. I don't think you'd be able to tell much of a difference if you didn't know her... but as of right now she's lacking the full growth on that "big" leg that's all you see along w/ the big claw when she's all the way inside her shell.

The theory that she'd have a more difficult molt due to the asymmetry of her body (only 2 legs, both on the same side) was (thankfully!) incorrect. The theory that both missing legs would be regrown
upon completion of the second molt after their loss is ALMOST true. I imagine she will have her completely regenerated legs upon her next molt, the 3rd after their loss.

Just a note to those who have crabs missing limbs...

[jmmc137]

i wonder if the same thing will happen with antennae.

[krabby_katie]

I'm guessing it will take longer for the big left claw though, right?

[ladybug15057]

Normally when a hermie is missing a limb, when they molt the first time after it is smaller than the original limbs. Sometimes they will be 'normal' size again with the second molt, but usually they are by the third molt. (as long as the hermie has a proper well balanced diet and plenty of exercise) As for the large pincher, this sometimes takes a few molts before it is close to the size it should be. Antenna seem to follow under this same growth as the large pincher.

[Carrie]

AK's regrown an entire antenna, too. That also took 2 molts. She appears to have no trouble using it (one of the bent "tasting" ones) just as it would've been originally. Others have regrown antennae, too.

That big claw (Stella? ) might take as long as 3 molts, or maybe more? It being the biggest limb of all... ?

Arwen's survived more molts than anybody in her 4+ years w/ me, so I haven't seen any crab go all the way to regrowing former limbs like this. I had no idea it would be more than 2 molts, but her biggest leg is now the size of all the other legs and the smaller leg she also lost and regrew is what appears to be normal size. Maybe the bigger the limb, the more molts needed?

It's amazing how they can regrow fully functional limbs and antennae that are capable of complete movement and sensation. I reasd somewhere that they can regenerate everything but actual eyes. They can regrow the stalks but not the eye inside. AK's got a weird eye--part of it is missing. She still has most of that eye and it didn't change during her molt. She's actually missing a bit of one eye, stalk-end and all. That's the one part of her that hasn't changed. I have no idea how she lost that little bit of an eye, but she wasn't like that until pretty recently, way before her most recent molt. Maybe somebody finally took a pinch back at the tank bully-crab?

I wonder what would happen if a crab were to lose both "tasting" antennae at once? Could the crab still find food, since that's how they recognize something is edible? I'm sure in captivity we could hand-feed such a crab but would this condition be survivable for an otherwise healthy crab? (Don't worry--I'm not going to produce this condition in captivity to test the theory! The antennae are safe!)

I wonder if at their fundamental level (cellular) hermit crabs and other crabs (who are considered 'primitive' b/c they have remained relatively unchanged evolutionarilly since they came to be in existence, millions of years ago)... I wonder if they're mostly stem cells? Cells that can 'morph' into a leg cell, or an antenna cell, or a big claw cell? (To use seriously lame and vague terms for presumably complex cellular structures...) In 'higher' life-forms, a loss of differentiated cells is permanent b/c the stem cells can't turn into anything after... hmmm... some point in the fetal stage, isn't it? (Reference today's controversial stem cell research.) The only aspect of a crab that's too 'advanced' to regenerate is the actual eye.

Yes, antennae do regrow, and they're fully functional. I've seen that happen--antennae are frequently broken due to a 'mishap' or a crab-fight. I'm stll amazed that they can be re-grown and fully functional as a part of the crab's nervous system. Your antenna-less friend will recover a full antenna, as did AK.

The big claw, tho, is something new to me. Go, Stella! I wonder how many molts that will take. I'm guessing 3 or even 4. Does anyone know?

[ladybug15057]

“That big claw (Stella? ) might take as long as 3 molts, or maybe more? It being the biggest limb of all... ?”

Due to its size they do seem to take longer to get back to the size they should be. My daughter had one of her hermies attacked during a surprise molt in the main tank a few years ago. We went out to do some errands for a couple of hours, and when we returned we found Shilo on top of Krabby who was freshly molted with Shilo pinching down into her shell. Krabby’s large pincher was detached, and it did take almost 4 molts for it to look almost normal.


“Arwen's survived more molts than anybody in her 4+ years w/ me, so I haven't seen any crab go all the way to regrowing former limbs like this.”

There have been hermies who we bought several years ago that were missing limbs. It certainly did seem that it took the large pincher longer to get back to looking normal than any of the hermies who were missing legs when we bought them.





The one who sort of threw a wrench into this (as hermies normally do) is my Straw Binker. When he was mutilated during a surprise molt in the straw main tank, when he regenerated his limbs they didn’t look much different to me? The coloring was really good too:



6 days post molt


Recovered from molt:


“It's amazing how they can regrow fully functional limbs and antennae that are capable of complete movement and sensation.”

This is totally amazing that they have this capability. What use to puzzle me with some of the ones we bought that were missing leg tips, how these were regenerated when there is no gel ‘nubs’? A gel limb I could understand, and looking closely as a fully developed gel limb one can see 3 ‘sections’ to it too.

“I reasd somewhere that they can regenerate everything but actual eyes. They can regrow the stalks but not the eye inside.”

Not quite accurate. Hermies cannot regenerate their soft curly abdomen. They can regenerate everything else, and yes this includes the eye. I too had read several years ago that they could not regenerate an eye, (or eye stalk) but I had bought a hermie Foxy lady who was missing part of her left eye stalk and eye. Being newer to the computer, and I did not have a digital camera at the time I do not have pictures of that. (but had posted about it on a group I belong to) With her first molt with me she did regenerate her eyestalk and had a ‘spec’ of a pupil. With each molt the pupil grew a little more and more.






I hadn’t taken her picture for a few more molts and CrabWorks had written a couple years ago on a group that I help moderate about Kate being in a scuffle with Jon and he clipped Kate’s eye off. I replied that Kate should be able to grow the eye back due to how my Foxy Lady had regenerated hers. I then took this picture to show Carol an update:



With a close up:



With Kates last molt here a little over a month ago, Carol had written that Kates eye had regenerated a little larger with this molt and still had her eye lashes too. I can’t wait to see an update picture of Kate! Hermies are quite amazing creatures.

“Maybe somebody finally took a pinch back at the tank bully-crab?”

Could be like Jon did with Kate?

“I'm sure in captivity we could hand-feed such a crab but would this condition be survivable for an otherwise healthy crab?”
This has happened in captivity. If the hermie had a few legs and a pincher as long as the food was ground up somewhat they were quite capable of eating and surviving until they molted. Even when missing their pinchers and a couple legs, and with TLC and a little coaching the crabbers have been able to feed the hermies until they molted again. For this reason, if they had their limbs and able to get about I would assume they would be able to also eat in the wild until their next molt.

“In 'higher' life-forms, a loss of differentiated cells is permanent b/c the stem cells can't turn into anything after... hmmm... some point in the fetal stage, isn't it? (Reference today's controversial stem cell research.)”

This has been studied/researched now by scientists for a few years in hopes of helping the “Higher life forms”. It is very complex.

“The only aspect of a crab that's too 'advanced' to regenerate is the actual eye.”

Nope, and from what I can tell, Foxy Lady does have sight too in the eye that she was missing, as well as Carol had written Kate has partial vision too.

[Carrie]

Wow!!! Thanks for the long post and wonderful pics! Not only informative but cute, too.

I'm happy to know that there's hope for Arwen's eye. It doesn't seem to bother her any, and she seems to have the same range of vision due to where the missing part is. I don't remember where I read about the eye-stalks... but it's so wonderful to see proof to the falsehood I took to be fact, and WITH pictures, too!!

I had a crab named Cecelia who had one hollow eye-stalk. You could shine a flashlight next to her eye-stalk and tell that it was hollow. Any idea why that was? That's the main reason I believed what I'd read about them not being able to regenerate eyes.

These creatures are, then, actually more fascinating and complex than I ever dreamed! To even be able to regrow EYES... wow!

I would LOVE to have a straw sometime... but I'm not buying any more until I can keep the 8 crabs I have alive.

One of the best posts I've ever gotten to see, and I don't mind being proven wrong here and there. That's why I post so many of my ideas: to see what other crabbers have to say about them. I've been largely operating in the dark for so long w/ them. And you never know if what you read is true or not until you encounter someone who's actually come across the problem themselves. Kinda like the allergy to dairy products that persisted as a myth for so long!

[ladybug15057]

Believe it or not, it was because of Foxy Lady that I finally got a digital camera one Black Friday. At one time I had no interest in taking pictures and putting them on the internet but as time went on with me crabbing there were things I started to want to share. One can write and write, but sometimes pictures can say so much more! I too read about the "Not being able to regenerate the eye" and it was on a group I now moderate, as well as many other places on the internet. I didn't notice Foxy's eye when I bought her, and my heart sank when I got her home and gave her the "Welcome home bath". So when she got the 'spec' with the first molt I was really surprised. If you look closely at the close up of her left eye compared to the right eye you will see it is not as 'full' as the right eye. (maybe it is me too since I have watched this progress since 2001? One thing for sure though, the eye is certainly one area that seems to take forever to regenerate to almost full size.
As for Cecelia's hollow eye stalk, not sure what to think. But if ones tanks conditions, (especially hermie friendly substrate) are in order mutations are hard to figure out why they happened. But one thing that can cause complications is the substrate. Several years ago crabbers tank conditions were all within order. This got me thinking and comparing substrates some used. I did (and still do some today) a LOT of research into substrates. I was shocked as to what some of my research led me to finding out. Once the crabbers changed their substrate the mutations and complications went away.
I love reading ideas of others, and especially when they share their findings through their experience and/or research they had done. Even with all that is known with hermies, there is still much we could learn too.
Sorry to be so long winded, but I have a habit of doing that sometimes.

[Carrie]

Very true about pictures! W/ digital cameras you can see the crabs like you can't w/ just the naked eye, thanks to being able to zoom in so close. I will definitely be checking out your pics when I don't have to work...

Cecelia didn't live thru that first molt. Her eye had that speck in it which at the time confused me b/c of that rumor that they couldn't regenerate eye stalks. I think as she got increasingly pre-molt she lost more and more vision. I know now that the crabs were actually unable to molt due to conditions, at least the big ones. I therefore haven't bought any crabs since 2006, in an effort to figure out the problem. I might have a better set-up than a lot of pet owners out there (the ones who don't even bother to go online) but it still wasn't right. The attempt with Calci-Sand last spring killed 4 crabs in one week (for which I still feel bad). The "jungle earth" was the closest idea to working, but Carol of Crabworks' coconut fiber bedding seems to be the right substrate at last. Arwen and Cecelia both had surface molts right next to one another at the same time, but Cece (who I was more worried about) didn't make it, and Arwen did.

I can say my substrate is a huge improvement now b/c everyone molted and survived this time around, and they all apparently needed to molt. Before, w/ the earth that was more like shavings than real earth (but wasn't like, say, hamster shavings) the little ones could make it but not the big guys. Except for Arwen. She's the biggest, golf-ball-sized. And now I'm so happy to hear that she should recover her eye. Arwen's survived the tough period but now she's got decent substrate to work with. These guys are all my survivors, crabs I've had since 2006 or longer.

Thanks again for the good news about missing eyes and limbs! Looking forward to checking out the pictures on your site when I have time!

[ladybug15057]

“W/ digital cameras you can see the crabs like you can't w/ just the naked eye, thanks to being able to zoom in so close.”

I also have a couple magnifying glasses here with the bifocal dot that lets me zoom in on things even on our smallest hermies here. Another good inexpensive investment.

“I think as she got increasingly pre-molt she lost more and more vision.”

I think this happens too when the hermies eyes cloud over when in premolt. I had a hermie Strawberry Shortcake (a red PP) whose eyes got so white and thick it almost looked like somebody wet her eyes and rubbed them in sugar. I had never, and to this day haven’t seen another with this ‘built up’ crust on their eyes. To this day I still don’t think she was able to see back then. But after she molted her eyes were so bright and shiny and nothing wrong with her vision. With her molts since she hasn’t had anything like that, just the typical cloudy eyes.

“The attempt with Calci-Sand last spring killed 4 crabs in one week (for which I still feel bad).”

Calsi sand even though very expensive is not a good substrate for hermies. It draws moisture and is drying to the hermies. Even if they do try to dampen it to burrow, it doesn’t ‘form’ for the tunnel they need. I know of a few crabbers whose hermies did dampen the calsi sand, and if they didn’t continue to put a couple drops of water over where the hermie was buried at it turned hard as a rock. Calsi sand also gets a stench to it when it is dampened. I also know of a crabber who mixed calsi sand with eco earth. She found one of her E’s who had passed away after molting. When she examined the little one, the calsi sand and eco earth was within the shell with the hermie. She stated it was hard as a rock and presumed because of that the hermie was literally stuck in the shell.

“The "jungle earth" was the closest idea to working, but Carol of Crabworks' coconut fiber bedding seems to be the right substrate at last.”

There is a coco fiber bedding and there is an eco earth. Both are 100% coco fiber, (one needs to read the package) but are in reality 2 different substrates. Carol uses the eco earth for Jon & Kates molting nests now, but uses small natural uncoated stone for their main tank. She does keep it damp over the UTH end, but Jon & Kate are out running her apartment for a few hours every day, even more so now that she lives in southwestern Florida. When the are returned to the tank at night, she stated they mainly hang out on the driftwood or the rainbow rock she has in the tank. So they do have dry areas as well in their tank to go to, and are not subjected to total dampness 24/7.