Do crabs sometimes undergo rapid growth when molting?

[Guest]

Last month marked the one year anniversary of my acquisition of one of my small males, Biff. About a month ago he went under for his 2nd molt (it might be his third but with 7 crabs and many molts it's hard to keep track).

Today He came back up and he looks like he underwent some serious growth. Usually when a crab goes under they come back up and don't really look much different. Before the molt he was the same size as one of my girls, lotus and now he is noticeably bigger than her.

I'm confused cause normally when my crab comes back up they don't really look any different from before.

[Guest]

My ruggie did that. Before he went down to molt, he was no bigger than my thumb nail.

Now, after his molt, he's a medium! It's crazy and very confusing. I was very surprised. x_X

[JediMasterThrash]

Well, if you can imagine that they can re-grow an entire BP from tiny stub to near original size in just 1 to 2 weeks during the molt, you can imagine they can buff themselves up a bit too. It's all rather magical in my view.

[Guest]

This may be a good thread to ask this. I don't quite understand moulting vis a vis growth. When they've outgrown their current exo, they moult. When they come up they have a new exo on. Since the new exo fits them and they come up the same size as they were when they went down, when do they grow?

[irishgirl45]

Seem to grow a bit during molting. I did have a crab that seemed to grow quite a bit during molt and when he came back up he was definitely bigger than when he went down.

[Guest]

I figured I'd grab a graph from my old Uni notes to help explain this.



Essentially the crabs are constantly "growing". They increase in mass at a regular rate, however they are confined by the exoskeleton. When they moult, their new exoskeleton hardens to whatever point it should in order to correlate with the crab's current mass. So the "chubbier" your crab is weight wise dictates how large they will be following the completion of their moult.

[irishgirl45]

Thanks for the information. I never get tired of learning about our little crab lets. They are always teaching me something.

[Guest]

Raen:


Thank you?? I still don't understand. Maybe I never will.

[Guest]

hahahahaha... Ok... Think of it like someone wearing Spanx (totally need to get some of those before cocktail dress season ). They can gain weight while looking the same size. You take the Spanx off and suddenly... ... No longer the same size. Same idea. Think of a crabs exo as a solid version of Spanx. So their ever growing body gets bigger and bigger, but is confined and squeezed in by their exo (Spanx) until it is removed and they get a bigger one that fits.

(Sorry for the bad analogy, but it's bed time for me and my brain is almost dead... It's what came to mind... lol)

[evre1's-mom]

I'm so glad to hear that because I thought I must be imagining things when one of my tiny crabs came up so much bigger after his molt. The other one who was the same size premolt definitely grew, but not as much as Tiny Dancer.

[MudCrabDude]

I'm so glad to hear that because I thought I must be imagining things when one of my tiny crabs came up so much bigger after his molt. The other one who was the same size premolt definitely grew, but not as much as Tiny Dancer.

That's nice to know. And a bit funny (and sad for me) primarily because the biggest problems I've had for about 20 years, prior to 2007-ish, were that:

1. my hermit crabs never grew

2. every time they molted, they shrank or never grew.

I might add that the conditions were virtually identical (deep substrate, sand moistened with seawater, heat, humidity) but with one major difference: I didn't provide seawater regularly.


This is the first year where I am proud to say I am finally getting it right. Thank you saltwater....

[Guest]

Thanks, Raen. But for you older folks: think girdle. :smt028