Hermit Crab

[angel]

There's been hermit crabs mentioned a couple of times this week. Once on this forum. We were talking about them today and a question came up. Hermit crabs have to find a shell, then move to a bigger shell when they grow, right? What happens if they can't find a shell, or can't find one that's big enough? Can and do they live without one?
Also, do they live on land or in water?

[jeremyh81]

I just noticed this thread, Angel.

Below is the info I posted in another thread about snail shells. I kept 6 purple pincers (Caribbean land hermit crabs) and did extensive research about caring for them in captivity.

If a crab can't find a suitable shell, it will just stay in the current one, keep searching, or even steal the shell of another. This usually turns out to be a good thing because both crabs end up with a better-fitting shell.

The main reason for changing shells is proper fitment. The shell's opening and depth must be just right so they can fit their vunerable abdomen into the shell and their large claw can cover the opening. Another reason is to change shells just for fun. Land hermits love climbing, digging, and changing shells. They also like shells that help them blend into their environment - I took a business trip to Gulf Shores and picked up a few camo-colored shells, which 2 of my 6 hermits immediately claimed!

Finally, if one is ready to molt, it will actually find a smaller fitting shell (can't remember exactly why). Then it will dig into the ground (substrate) and shed its exo. The old exoskeleton is eaten for nutrients and a new one is grown. Once the crab surfaces, it will search for food, water, and a larger shell.

Land and marine hermits are extremely fascinating, but the land variety are very demanding to care for. They do require fresh dechorinated water daily and some salt water (mixed using FW aquarium salt). Being of the arthropod family, their food cannot contain any pesticides. Otherwise, they aren't very picky eaters because they are considered scavengers. The terrarium's air must have a relative humidity of at least 70% and temp shouldn't drop below about 74F.

I just hate to see anyone considering a hermit crab as a throw away pet. They can actually live in captivity for 20+ years and reach the size of a grapefriut. In the wild, some have found much larger specimens with an age of nearly 75 years!

More to come!

[jeremyh81]

Please "just say no" to painted shells. The paint used is very toxic to the crabs and hermit crabs that are found in painted shells have usually been forced, very inhumanely, into the shells. They really like the most natural shell one can find.

[jeremyh81]

Here's a great forum for anyone looking into hermit crabs:

www.hermitcrabassociation.com

Many members have been keeping crabs for 10-20+ years and have unlimited knowledge!

I also have gained much knowledge over the 4-5 months that I kept mine. With the care requirements being so demanding, I eventually gave the 5 of 6 survivors (someone cannibalized a molter!) to a good home.

Regarding the question about them living in/out of water: land hermit crabs can, and sometimes will, spend 10-15 minutes under water (decholrinated freshwater). I always wanted to build a 6" deep pool in a 29g tank for my hermits just to save me from changing their drinking water every day. While reading info about pools for the crabs, I found one person who had built a small pool that had a few, small FW fish in it. He reported that a couple of his crabs would just hang out at the bottom of the pool.

All hermits have gills, but land hermit crabs' gills have adapted to breathe air - humid air, that is. But their gills must be moist at all times. If they were to dry out, the crabs would slowly suffocate to death. One way they naturally moisten their gills is to store water in the back of their shells. This can only be done if the water dish (or pool) is deep enough for them to partially submerge themselves and fill the shell with water.

Keeping a fully enclosed aquarium with a glass lid (never use screen terrariums and covers) will also help keep the air humid enough to help with breathing and preventing the gills from drying.

Finally, they aren't very demanding on substrate. Most all experienced "crabbers" use play sand ($2.50/50lbs @ hardware store). The depth should be about twice the size of the largest crab and dampness should be similar to the moistness of sand used to build a sandcastle. This is critical to allow the crabs to dig into the sand for molting, and it also helps keep the relative humidity high within the habitat.

Please feel free to ask me any questions or refer to the website mentioned previously!

[jeremyh81]

I know I'm going to town here, but I found the pics of the crabs that I had kept:

s648.photobucket.com/albums/uu201/jhenson81/Hermit%20Crabs/

And their "crabitats":

s648.photobucket.com/albums/uu201/jhenson81/Crabitats/

[angel]

They look very well cared for. Anyone considering hermit crabs could learn a lot from you.

[jeremyh81]

Thanks!

In all honesty, I got into hermit crabs while on a trip to Gulf Shores. One of the souvenir stores was offering a free crab w/ the puchase of a kit (critter carrier, clam shell for feeding/water, a tiny amount of gravel, and a small sea sponge). So I bought a kit on impulse and picked out a little hermie w/ a natural shell. All without knowing a single thing about keeping the crabs. While riding back home, I pulled out the laptop and mobile internet card and started reading.

The main thing that got me hooked is when I learned that the name "hermit" crab is actually a misnomer - they are really happiest in groups of 2 or more and are not really "hermits", by definition. Land hermit crabs love to have friends!

When a new tankmate is introduced or one walks near another, they'll actually have little "sword fights" with each others' antennae. This is how they greet each other and possibly communicate. Another form of communication is a croaking or clicking sound that some believe is made by rubbing a pair of legs together much like crickets. This is usually a warning sound when they feel threatened, but I never heard this from the several that I kept. Even when I picked them up, the shy ones would just retract into their shells.

I'll save the rest of the info for any questions because I could almost write a book from what I've learned, if I could put all the info together in an organized way. ;D