The Shell Removal Experiment

[angelbear]

This is a continuation of the Something Interesting topic I created on Sun Feb 02, 2020 8:04 am. As the experiment has provided decent interest, I decided to organize it a bit more to make things easier to follow before they get to buried in ever ones comments.

The Theory:
In their natural environment, hermit crabs are unlikely to come across a large cache of shells on a day to day basis. By providing them shells daily it is my thought that they become disenchanted, and less inclined to change shells due to the ready availability. From this On a Tiny Caribbean Island, Hermit Crabs Form Sophisticated Social Networks I found out that hermit crabs will wait anywhere from 15-minutes to up to 8 hours for a chance to upgrade their shells. I am also aware that we as Hermit Caretaker's provide plenty of shells to avoid shell fights. But how to balance the two, so the hermmies can have enrichment, and to have no aggression.

The Experiment
I plan on removing all shells from their enclosure on Sunday Mornings, only to add back in the required 3-5 shells per crab on Friday nights. This time of no shells is to mimic the days they may not come across any shells in their natural habit, balanced with giving them roughly a 48 hour window to try on shells to prevent shell fights and aggression. It is my goal to get the community to become involved. This is to collect varied data to make sure that the crab species, size, and colony size are taken into consideration.

The Participants
One Medium-Large Ecuadorian (Coenobita Compressus) Name: Speedy
One Medium Purple Pincher (Coenobita clypeatus)

The Time Frame:
This experiment will go on for 1 Year. It is my hope by then with the Communities involvement we will have enough data to tell if this is a success, cautionary trial, or failure. I have started this on Sunday January 19, 2020 [so about a month ago].

Termination of Experiment
This experiment will be terminated if there are multiple cases of shell or crab aggression present and/or reported. The Hermits Safety is my number one priority. These will be taken on a case by case account and evaluated to see if lack of shells was the underlining cause.

My Data Collection So Far
This data spot will be updated with a summery every Sunday to add the weeks data. Any detailed notes can be found in the comments below.
Week of January 19th - No change observed
Week of January 26th - The Hermits became immediately interested in the shells when they appeared. They often rolled them around and checked them out.
Week of February 2nd - I have noticed increased activity even from my normally nocturnal Purple Pinchers. They are coming out during day time hours and seem to be exploring the enclosure, possibly for shells, unsure the reasoning behind the activity increase.
Week of February 9th - So far no one seems to show signs of aggression. Shy Guy changed shells anywhere between 8 to 10 times. He seemed to alternate between his old Babylonia shell and one of two green turbos. He finally settled on the Green Turbo . Speedy tried on a different green turbo, but ultimately switched back to the original shell. He was seen inspecting a few others as well. Thing 1 and 2 showed no interest.
Week of February 16th - Speedy my lone E showed intrest in the shells. Even a shell he normally has not had intrest in before. He settled on a large Green turbo. Speedy practically ran to the shells when they were noticed and spent the two days turning over and examining several of them even after the fact. The other three were down molting. Although thing 1 did shown up late Sunday night.

[angelbear]

Future Participants:
here I will keep tabs on any community members that would be willing to try this experiment with me.

Please Provide the Following:
Colony Size
Hermit Specie if known
Hermit Size to the best of your knowledge.

Any videos, information or behavior can be noted below. Conversation is welcome.

For Sizing:
Teeny = marble
Small = quarter-50c piece
Medium = 50c piece-golf ball
Large = golf ball-tennis ball
Jumbo = baseball
~Lets have some fun~

Links - (Shell Removal)
Colony Size:4 crabs
Hermit Species:PP I think
Hermit Size:
-teeny PP (Cookie & Strawberry)
-1 small PP (Crabby)
-1 medium PP (Mr. Crabs)

aussieJJDude (Shell Removal)
Colony Size - around 6 to 8 crabs. A couple have the same size and shell, so a little hard for me to keep track at times.
Species - 1 C. perlatus, rest C. variabilis
Size - Perlatus large/jumbo, rest are small to med/large

Overmountain1 (Control) -
information to come

[angelbear]

@curlysister - @RiNiKy506 - @Crabby7Crabber - @wodesorel - @Links - @Hermiesguardian - @Maddamay32

Sent because you posted in the original thread.

[JoeHermits]

I have more shells than I do tank space, so I tend to swap them around once every few months. The crabs will occasionally check out suitable shells once added but otherwise show no aggression, stress, or changes in behavior.


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[Links]

I’ve already removed my shells since I’ve read your topic. Lol. I have more shells on the way as well. Also toying with polishing shells.

What would be real cool is if you could put one big shell in there and they’d all line up. Not sure if possible in captivity. Not sure it’s ok to try either.


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[angelbear]

I’ve already removed my shells since I’ve read your topic. Lol. I have more shells on the way as well. Also toying with polishing shells.

What would be real cool is if you could put one big shell in there and they’d all line up. Not sure if possible in captivity. Not sure it’s ok to try either.


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If you are willing to post how your crabs are doing here it would be appreciative. Also if you could post your colony size, type ect at mentioned above.

[angelbear]

I have more shells than I do tank space, so I tend to swap them around once every few months. The crabs will occasionally check out suitable shells once added but otherwise show no aggression, stress, or changes in behavior.


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Which is a good control group. Not trying to break what works but it is a intresting topic of discussion all together.

[Hermiesguardian]

I'm going away this weekend, so I'll wait till I get back.

[angelbear]

I'm going away this weekend, so I'll wait till I get back.

That is fine just let me know

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[Crabby7Crabber]

I might try it, just want to see what happens with yours after a while!

[angelbear]

I might try it, just want to see what happens with yours after a while!

Thats fine too.

[Crabby7Crabber]

Thats fine too.

Thank you! I'm really interested to see what happens!

[Links]

If you are willing to post how your crabs are doing here it would be appreciative. Also if you could post your colony size, type ect at mentioned above.

Well I’m not sure. We lost the one I posted the gill pic of course. I couldn’t get a pic like that of a live one. So that left us with two (1 medium and 1 small). The small dude been MIA for about a week. Maybe molting again or only coming out at night. I think he molted a couple months ago.
So I broke down, doing what I told myself I wouldn’t, and bought two more 2 days ago. We went for just one but I have two girls and my 2 year old saw one and called it Cookie! So now we have cookie and strawberry (both small PPs I think). I haven’t had a real good look at them. I also added that craft mesh to the pools because they are little.
So in October we started with one small PP (crabby) and he’s been pretty active since we got him. Also grown! But he may be molting again or just hanging out underground. We got him two buddies (mr crabs and Crabetha [passed]). I suppose golf ball size. Is that medium or large? They were shipped further than Crabby so maybe that has something to do with their stress? When they were new i would see them drinking salt and fresh water a lot. And food was being eaten well.
They are in 1 in. Opening shells and can’t tuck all the way in. I have two 1&1/4 on the way. I was weary of buying 1in - 1&1/8 because last time I did they were really 1 in and smaller. And I have some closer to 1&1/2 in.
Anyway, our Crab Clan seems to just hang out most of the time including the two new little guys. Mr Crabs (the largest) started to slightly perk up. More antenna movement. Caught him eating honey but he saw me and moved away. Seems like I stress them. I try to be slow and easy.
I tested the fresh water last night and all reading are good, but for some reason pH was 8.3. My tap is 7.8. I don’t know what would cause that. My KH and GH is the same so it’s not like it’s more magnesium or calcium carbonate. And TDS is 150. I’ll have to check TDS of my tap again. I thought it was 150 but could be 125. So anyway I did a 90% change. BTW I need a saltwater master test kit chart. Just the chart. Anyone know where I can find one?
Also my DIY fan has been off since we lost Crabetha. So the humidity has been over 90 and even 97,98 at night. The blanket draped over the top hung over the front a bit which would keep some condensation away. The fan kept it away as well. Yesterday I peeled back the blanket a bit to allow a gap in my lid to be exposed. That dropped the humidity a bit. It was 85% last I checked. My day temps are 81-82 (two thermometer readings) and night temps 78-79. I suspect it’s 77 since peeling back the blanket. Also I’m sure it’s 1-2° more or less than these numbers when closer or further from the UTH on the back.
Sorry for the novel. I know nobody likes to read all this. And thanks for your concern. If these guys don’t make it I should probably call it quits.

Edit to add :

The Crab Clan
4 crabs all PP I think
(1 golf ball size and 3 small)
Largest to smallest
Mr Crabs, Crabby, Strawberry and Cookie

She’ll sizes I have:
Have more 3/4 and smaller on the way
0.75. (3/4).
0.80
0.83
0.86. (7/8)
0.90.
0.92
0.93
0.95
0.97. (1)
2, 1&1/4 on the way
1.40. (1&3/8)
1.52. (1&1/2)

I may need more shells to help with this experiment.

Edit again: I’m the edit master uh.

I used calipers to measure my shells and I put the caliper a good ways in the shell to avoid measuring the flare out. So depending on how someone measures my numbers could be slightly lower.

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[w h a l e b o n e]

Not sure if I'm going to participate yet, but just some advice to help keep this accurate and repeatable, maybe make a standard way for sizing crabs? I know there's some varied opinions on what constitutes what, so maybe stick to one measuring system. And yes, definitely get some control groups. This sounds really interesting and I hope it goes well.

[angelbear]

Not sure if I'm going to participate yet, but just some advice to help keep this accurate and repeatable, maybe make a standard way for sizing crabs? I know there's some varied opinions on what constitutes what, so maybe stick to one measuring system. And yes, definitely get some control groups. This sounds really interesting and I hope it goes well.

That is a good point and i will look into getting that up after work. And yes I am looking for one or two control groups.