Claude is at his 'molt or die' point today... he's going to molt above ground (he didn't want to dig at all). He's spent a lot of time in his water dish in the past two weeks. One night he was in there for about 2 1/2 hours, mostly rubbing water into the gel-limbs that will hopefully be his new claws--they're pretty big and they look uncomfortable. Of concern... the gel-limbs have made hand-feeding him difficult, since they're growing right next to his mouthparts, almost gettting in the way. His appetite is gone--he's even gone so far as to use his front legs to make me stop feeding him--he's obviously saying "no." Now I only bother him to put him in the water dish. He'll still climb out when he's done, but I imagine he'll stop after today. (Yesterday--the entire day--he was perched on the side of the dish, not climbing in or out).
Claude is now hanging out of his shell a bit (but still holding on); very dry-looking, dull skin (colors are more pale than usual, too); antennae action is almost gone; movement just plain looks uncomfortable, what I call "creaky," sort of arthritic... His gel-limbs are pretty big now but since he's a small crab I can't make out if there's a miniature replica of each claw inside them (which I'd hoped to do). They're the only part of him that looks moist now.
Due to these signs I think he's going to molt w/in the next few days, if not tonight or tomorrow. I've upped the humidity and heat in his tank and I'm putting him in the water dish twice a day for as long as he wants. (He might molt IN the water dish, which means he'll have extra moisture and the old exo will be easier to slip out of).
The Molt:
When Kali IV--my repeat surface molter--was at the point of 'crisis' (molt or die) she was exactly like this. I thought she was dead based on the way she was barely holding onto her shell and she'd come out of it up to where the soft part of her abdomen began. Not sure but she might have lost the ability to hold onto her shell if I'd done something very bad like shaken her. At the time I just held her, thinking she was dying. Then I realized that her eye-stalks were clear, instead of dull. That's when I knew she was molting!
I held her in the palm of my hand and started spraying her with water.
The skin at the back of her abdomen, where the exo meets the soft part, was first to crack. (This is also the skin that can't have water rubbed into it when the crab is hanging around the water dish). This part of the exo, from the soft part up to the 'joint' where the 'head' begins seems to be more supple in comparision to the rest of the exo. This segment contains the 4 shell-legs which the crab will use to hold onto its shell, as well as retract back into the shell and come out, whichever.
After the skin at the edge of the actual exoskeleton had cracked in the back, Kali started to retract out of her old exo, much like if you were to pull your hand out of a glove if we were to hold onto one of the fingers and pull your hand out backwards. (I use this analogy b/c that's what the actual physical process of molting reminded me of: slipping out of a glove, with each limb equivalent to one of our fingers).
She was going thru huge muscle contractions. Expand and contract, expand and contract. Her new skin was so soft and with each contraction she'd move backwards out of her exo a little more. As she was 'backing out' of the old skin, each limb was being pulled thru the narrow holes that can be seen on a freshly molted exo, where each separate limb joins the body. Kali's soft new skin was SO soft that each limb--including the big claw--was easily able to pull through those tiny holes. And, having seen that firsthand, I would have to call that a definite miracle of nature!
The muscle conractions were so strong that they looked painful. The frequency was comparable to the time it takes you to open and close your fist, and as rhythmic. It's a process that, once started, cannot be stopped. If a crab dies during molting it could be, in part, that the crab's body simply becomes exhausted and can't keep up the contractions necessary to move backwards out of the old exo.
By now Kali was almost all the way out of her old exo--at this point most of the length of her legs and most of her claws could be seen, but her 'head' (antennae, mouthparts, etc.) was still partially inside the old skin. You could see the base of her eye-stalks, which were tightly together and pointed in the direction of the old exo. By this point I don't think she was holding onto her shell at all anymore.
Her mouthparts and antennae and the area surrounding them underneath--including the four 'shell-legs', came off last, during a brief period, at the very end, of lesser contractions. This skin, like the top part of her exo that had cracked first, also seemed to be more supple (for exo).

The contractions were so strong that, when her 'back' became visible, the new skin actually seemed to pulse in and out... almost to fold... strange. In a way it was like seeing a person's chest rise and fall with each breath--only an in/out pulsation. I would have to compare the whole process, in human terms, to something as extreme as childbirth. (I don't have any kids myself, so that's a rough analogy). Once I realized the process was over I stopped spraying her with water. (Water on the new, soft, exo prevents it from hardening properly.)
Once the exo was completely shed she was able to retreat back into her shell, which was still tilted backwards. The freshly shed exo was moist--I believe over the course of the next few days following a molt, it dries out, becoming tougher and more difficult to eat. The softest parts of the exo were facing towards her shell--the first part of the exo accessible to her after her new skin hardened up and she would be able to eat it.
Kali, being perhaps TOO tame, didn't retract back into her shell for very long, and she didn't go as far back as she could. I held her in my hand a while longer. After a while she came back out of her shell, still soft, and started eating her exo... which isn't typical behavior. Normally, of course, they hide in their shells for a few days and the new exo hardens. She just had no fear at all, I guess. She knew my hand by smell and feel (she'd pinch anybody else who picked her up) so I figure she knew she was safe. Or else she didn't want to miss anything. The second time she molted in my hand she did this, too. Immediately took to eating and drinking.
Before a crab's new exo hardens... and you happen to be years younger and curious and touch the soft big claw... the crab will have your thumbprint in the hardened exo until the next molt. This is also why antennae sometimes end up a little crooked--they end up at whatever angle they're in while the crab is deep in its shell, recovering, while the new skin hardens.
The whole molting process took about half an hour. (Kali was something of a mascot at work so I was able to call in late b/c "Kali's molting!! In my hand!!") Kali was a medium-jumbo crab. The exos of the smaller crabs--as I read somewhere--are more supple and thinner than the exos of the jumbos. The little guys don't have all those bumps and pores you can see on a jumbo. I imagine that the small guys molt faster.
Immediately after the molt Kali went for anything calcium/protein--exo first, then Tetra BabyShrimp and cuttlebone. I showed her another shell (which she later moved into) and she started scraping at it w/ her little claw and apparently wanted to eat something out of the inside of the shell... and I thought, what are shells made of? Calcium! So I gave her the cuttlebone, which she held onto for about 24 hrs and ate and ate... I figure her nutrition, in captivity, was such that she needed the extra calcium/protein wherever she could find it, b/c there probably wasn't enough of these nutrients in her exo, even tho she ate most of it. She knew what she needed and how much of it. She was nutrient-starved.
Had she wanted to retract into her shell and hide for a few days I would've put her in iso and left her alone. As it was, she wanted to walk around before she was strong enough. I held up her shell for her so she could build up strength as she began to walk again. When I realized she was going for everything calcium/protein... well, her next molt (again in my hand) was about the same, but she regained her strength in a few days instead of about a week and a half. Calcium/protein is crucial for a freshly molted crab to recover and--perhaps--to begin (already??) growing the next exo underneath.
What happened to Kali? Her final molt wasn't successful. I learned that molting isn't just a period of a few days--the cycle BEGINS with the molt, rather than ending w/ it. Therefore when I moved twice in two months and disrupted the normal heat and humidity (I hadn't mastered humidity yet anyway) her molting cycle was disrupted during the crucial final month. (Spring moving... and molting season appears to be spring, too.)
Hope this makes sense. And anybody who reads this... keep Claude the Clawless Wonder-Crab in your thoughts b/c he's going to be going thru this in the next day or so, I think.
Kali was the exception to every rule. She started walking while her exo was still soft... she had NO problem w/ being handled thru all this, but I used to have her w/ me everywhere. I think she was practically human, or as close to it as a crab can ever get.
In every other case besides Kali, the crabs have either molted underground or, for surface molters, when it's dark and still (i.e., when I'm not hovering w/ the digital camera and a light on to 'tape' the process). And in every other case nobody's been up and about an hour after molting. The usual rule of 'leave me alone!' applies. Arwen (a little bigger than Kali IV) got to the point that Claude is at now--'molt or die'--and I really think she waited until I went to bed at 5 AM--she's the one I was trying to tale a movie of w/ my digital camera. I might want to get visuals of a molt but she's not going to cooperate. I doubt Claude will, either.
Sooo... anybody want a descriptoin of a shell change? Kali also took to changing shells in my hand. If you really watch closely you can 'read' the body language (legs and antennae) and tell what's going to happen next. I have a video of Arwen (AK) changing shells last summer. Which I haven't figured out how to post on here.