"Elderly"crabs?

[hermieluv1]

Caring for my 2 recent sick crabs, who show signs of pps, reminds me of the care I give my elderly parents. Which got me to wondering, how old are my crabs? Any way to tell for sure?

These 2 guys are pretty big, and both have severely rounded claw tips, but show no signs of wanting to molt. So, like humans or other animals, do their hormones eventually stop flowing and they die of old age? I would think so.

I searched the topic and there is a little info out there, though who knows how accurate. If going by what I read, plus common sense, a small crab would be around d 10 years old, a medium 20ish , and a large maybe 25. They referenced Carol, who has the 2 jumbos, which are 29, so in that respect, the information could be somewhat accurate.

Any other info on this subject would be appreciated!

[Drakezilla]

I'd link you to our size chart in the care sheets, but if they're sick, it's only going to stress them out. Can you give us an approximate size?

Ie; a kin to something like a golf ball, baseball, tennis ball?

I'm not sure how their aging works, as it's hard for us to study their entire life cycles we really only have guesses. 8/

[aussieJJDude]

Each crab grows differently, there is no accurate way to measure... However, in saying that I have heard of cutting off their antennae & counting the rings. However it seems to me a rather cruel and rather inaccurate.
A good rule of thumb is: the bigger the crab, the older it will be!
Off memory, they have two hormones to help get them into breeding - I forgot what they are called, an more experienced crabber thats good with remembering impossible words might be able to help - one is to hold off the moulting process. This usually is due to the conditions aren't right. They will "build" up of that hormone which could eventually kill them.

[Drakezilla]

...Rings on their antennae?! Really? Like a tree?!

[aussieJJDude]

...Rings on their antennae?! Really? Like a tree?!

From what i can gather, yes.

[wodesorel]

Carol's remaining crab is 39. And even she has said she doesn't think they've grown the same in captivity as they would have in the wild. Hers are smaller than other jumbos that have been collected for sale. When Kate passed away a few years ago, it was widely accept that it was from "old age".

However, crustaceans don't age the way other animals do. They don't undergo a degradation of cells like mammals do. They don't slow down or get elderly before they die. What happens is that with age, the effort of molting becomes much harder and takes more resources, to the point where they don't have enough energy to complete yet another molt and they die. In some species, the oldest animals stop growing completely, and once they stop growing they stop molting so their exoskeletons are what ends up failing.

There is no way to know while the crab is alive how old it is. And since they molt they completely replace, rather than add to, everything hard on their body. There have been studies in lobsters and marine crabs that should work the same way in hermit crabs in that there "rings" - like tree rings - that form in their eye stalks. However, there's no guarantee in hermit crabs that these rings would be representing a one-year period like they do in lobsters. It could instead represent how many molts they've had in their life. It would take rearing crabs in captivity and then dissecting them at known intervals to know for sure. (Also, unlike what some other sites report, hermit crabs do not have otoliths like fish.)

We'll know more about the age of young crabs as Nat_addicted to HC's and Curlz's babies age. It's looking though like we're grossly underestimating the age of small crabs, and your guess of around 10 years for the smallest of crabs found for sale may be about right. When I first started crabbing people said those crabs were 2, 3, 4, or 5 years old, but looking at how tiny Nat's are after a year, it would have to be on the very far end of those suggestions.

It's been reported that jumbo crabs in the wild are between 50-70 years old - I have never tracked down a legitimate source for this. It may very well be true, but I really have to wonder if it's a crabber's myth that got out of hand over the years. We know for certain that they can live 30-40 years in captivity. Anything past that is a guess. They could have the ability to live longer in the wild. They may live longer in captivity. In any case, a focus group of two hermit crabs does not a scientific study make.

I usually go with the smallest of smalls being around 5 years, and a jumbo being at least 20. Anything more than that is truly a best guess given the different rates in molting, and the influence of diet and food availability and a whole host of other variables over their lifespans.

An honest "old age" crab though is a massive beast that takes a 2" opening shell (a 4 inch long Jade Turbo) and fills it to the brim. Anything smaller than that should still be able to molt - if it's healthy and not injured and not trying to make that initial adaptation to life in captivity.

[hermieluv1]

Excellent information! That is much more than I expected! And very interesting.

So, going by that, the 2 bigger-than-a-golf ball, smaller-than-a-tennis-ball crabs might be around 10? And as you say, who knows if that is crab teenage, middle aged or whatever in crab years?

[jarteta97]

It really is interesting. I actually had a small crab become large in one molt, so there could be a little variation. When she came up, I could NOT believe it was her, she got so big in one molt. And she was only down about 3 weeks, so I know it couldn't have been a back-to-back molt. I think it will be years before we truly understand/know the aging process of crabs.

[Crabinski]

Excellent info, Wode! Goes a long to explain why captured jumbos don't do well in captivity as it would be too hard an adjustment after living 20+ years in the wild.

[Drakezilla]

Wow! This is so interesting! So, were Carol's crabs ages factored in from a guesstimate in the wild when she got them? Ie; if they were smalls or teenies like 5-7 years then she added the time under her care in captivity? Or was she only going by their age according to how long she had them? In that case, I wonder what Jon's shell size/approximate size is!

And what about crabs who are serial molters? I wonder, will they be bigger at a younger age?

Mine just hit jumbo status after a 3 month molt -- I though he was so much younger! Now I'm worried! Lol.

[CallaLily]

Wow! This is so interesting! So, were Carol's crabs ages factored in from a guesstimate in the wild when she got them? Ie; if they were smalls or teenies like 5-7 years then she added the time under her care in captivity? Or was she only going by their age according to how long she had them? In that case, I wonder what Jon's shell size/approximate size is!

This old video shows their size well at that time. I'm pretty certain it was/is how long they've been with her.
http://m.youtube.com/watch?v=hcwXBs7Ax1g

[wodesorel]

39 years is how long she had them. She brought them home as small crabs in 1976 (bicentennial vacation). So yeah, tack another 5 years(?) onto that. Jonathan Livingston would be 45 or maybe even 50 now. I hadn't even stopped to consider those extra years.

OMGOMGOMG I FOUND IT!!!!!!

I have been trying to find this photo for YEARS. Ever since geocities shut down!!!!
VIVA ARCHIVE GROUPS!


Photos of them and the shells they wore to that point, taken in 1985.

THE PAGE LIVES! Check out more photos of them as babies here:
http://web.archive.org/web/200910262351 ... abs/carol/

Edit: and another of Kate and her original shell, taken 24 years apart:

[Crabinski]

Thank you, Wode, for finding that link. How marvelous to watch the growth of the crabs over such a long period!

[CallaLily]

Those are awesome pics! So glad she thought to take and save them. Thanks for digging them up Wode!

[megmaholm]

Those pics are amazing!! Especially the last one with the 'baby' shells next to Kate...wow.