Crabs love heat

Post by **JediMasterThrash** » Wed Jun 08, 2005 10:02 am

Since it turned summer up here and the house temperature is now 75 instead of 68, the temperature in some parts of the tank goes as high as 83o.And I've found that my crabs love it!. Whenever it's a hot day and the tank gets above 80, the crabs all all out right in the middle of a sunny day chillin on the plants or basking on the cholla or wandering around.The humidity still stays around 80 so no problem there.

Guest · Post by **Guest** » Wed Jun 08, 2005 12:04 pm

I thought above 80F wasn't good for them. Am I wrong? LKL

Guest · Post by **Guest** » Wed Jun 08, 2005 12:24 pm

My crabs love it pretty warm too. During the day it gets into the low 80's and they are very active too.As long as they have a way to cool down (plenty of water, deep enough substrate, shaded area etc.) I think it is OK... I know that my straws really thrive in the warmer temps too.

Guest · Post by **Guest** » Wed Jun 08, 2005 1:44 pm

I agree, my Hermies like it when the heat in the tank is above 80* during the day, but I also have a big enough tank where they can go to the cool side which is 76*. My humidity is always above 75 and they love it.Sandra

KittyCaller · Post by **KittyCaller** » Wed Jun 08, 2005 2:35 pm

I would like to point out to new crabbers to be careful not to take this too far. While lower eighties may be just fine, ninties may be TOO hot. (My crabs are the same way; I don't freak out immediately if the temp goes as high as 83 or so. Around 85, I might start try bringing it down, but I haven't had it get that high yet)

Guest · Post by **Guest** » Thu Jun 09, 2005 12:55 am

My tank is set up with 3 levels, 3 different substrates, and lots of climbing things...I use overhead heating, so the bottom level, which is at least 3/4 shaded by the upper levels, stays around 73-75 degrees and the upper levels get up to around 83 degrees. My 2 straws are almost always on the upper levels. One is ALWAYS basking as close as he can get to the lights. The other only goes down to dig , molt and get salt water on the bottom level. My E's will hang out on all levels, but my PP's are always on the bottom level, unless they come up to the 2nd level to get food, and then go right back down....that's why I like a big tank with multiple levels for the differenct species, since they all seem to have different preferences.

Willow · Post by **Willow** » Thu Jun 09, 2005 1:30 pm

I use a heat lamp (with a ceramic heating element, not a light) with a 75 gallon tank and I don't have a problem with the humidity at all. I think with a smaller tank it might be an issue, though. Since it's pretty hot here now, I thought about unplugging the lamp (I did unplug the UTH), but all the hermies just love it, even when it's 80 degrees outside, I still find the Straws, especially, basking under the lamp. I figure if they get too hot they can bury in the sand which, with the UTH off, is nice and cool. My "panic temp", when I'd turn the lamp off, is 88 degrees. I figure any hotter than that would be too much. So far the tank's highest temp has been 86, and the crabs were SO active! Sometimes, I make it "rain" in the tank, by spraying the sides and top until they're dripping, and the highest activity level I've seen is right after I made it rain, and the temp was 85. All the hermies came out and did a few laps. They also eat more when the temps are higher.

NewCrabber · Post by **NewCrabber** » Thu Jun 09, 2005 4:18 pm

I agree bulbs can and do effect humidity depending on the size of the tank. I use two 15 watt moon glo bulbs on a 40B and have no problems at all. I've used one 15 on a 10G and it's near impossible to maintain both proper temp and humidity unless I were to monitor it and make adjustments constantly, day and night.lkl, Their natural environment can be much warmer than 80 - 83° mid day in the middle of summer. The problem with a temp much over 80° in captivity is high humidity and temp in an enclosed tank makes a good breeding environment for mold and bacterial growth. Also, they are very limited as far as seeking cooler surroundings when they feel the need.

Jedediah · Post by **Jedediah** » Thu Jun 09, 2005 8:01 pm

And they cannot cool themselves down anymore when the temperature and humidity is too high, which apparently causes the bubbling some of us have observed.I copied a post from the HCA, the whole thread can be read here:http://hermitcrabassociation.com/phpBB/ ... 8&start=0I am posting the findings about this phenomenon here as well as in a related thread...I thought it too important a topic, and want all to see this...I wrote to an expert on Crustatea and Decopodae, and he has also done some biological work with respect to Land Hermit Crabs. I am reporting what he told me. Something to note though, he does not provide a definitive tolerance level regarding temperature. But note, relative humidity is temperature dependent...meaning that in order for your humidity to be higher, so must your temperature be higher...This is for dehydration:Most crabs bubble brown fluid when stressed and rough handling is often enough to provoke it. (rough handing is classified as arid conditions below 65% RH, temperatures exceeding 33C {92F}, where no cover is present)The brown fluid is regurgitated from the fore gut and bubbles in the exhalant respiratory air streams, which exit close to the mouth. The fluid contains surfactants (A substance composed of lipoprotein that is secreted by the alveolar cells of the lung and serves to maintain the stability of pulmonary tissue by reducing the surface tension of fluids that coat the lung.) which cause the bubbling. This effort does further damage the gills and they will die up to 3 days from the time they do.This is pertaining to OVER saturation (there is more than one process, as the crabs have a couple of ways to control their temperature:Coenobita carry fluid in the spiral part of the shell (generally clear and colourless) and this can be used for evaporative cooling of the body at high temperatures. The osmotic pressure of the fluid is regulated by the animal by selective drinking of water of different osmotic concentrations (in our tanks that is regular water and ocean salt water...which they use more for cooling). If the fluid available for drinking and adding to the shell is more dilute (not enough salt) than preferred, the crabs will enhance evaporation from it to make it more concentrated and may hang out of the shell to achieve this. If the humidity is too high, they will not be able to achieve this, and will overheat. This results in them leaving their shell. For details of these mechanisms you need to read de Wilde 1973 or the summary in my chapter in Biology of the land crabs 1988 (copy attached) - references are given in my 2003 paper. Your crabs at 90% RH may be trying to increase evaporation either to cool or may be trying to concentrate shell water or cool themselves what temperature were they at? In Celsius the temp ranges you are using will be ~22-28C. (72-84F) I would think these should be in the acceptable range.So what this means is that temps over 84 and humidity over 85% can only be tolerated in a closed environment for a short time. While some will be able to burrow in a cooler area of a tank, it is important that there is a temperature range! The accepted ranges ARE: 72 - 84 degrees for temperature...the RH (relative humidity) ranges are from 72 - 82%Hopes this explains a little clearer why this occurs!

Guest · Post by **Guest** » Fri Jun 10, 2005 12:27 am

I have no problems with humidity in my tank (which is a 30 gallon by the way)...it ranges from about 80-83 at the lowest level to 70-73% right next to the lights at the top (I have 3 sets of gages to measure temp and humidity... at the very bottom, middle and very top of the tank to make sure everything is good for the crabbies). The overhead lighting is a hood that allows for a reptisun 2.0 flourescent bulb that I have on a timer to come on from 9 am to 5 pm every day. The other sockets in the hood allow for regulartype bulbs...in those I use the red lights, one that is 15 watts and one that is 25 watts. These I switch turning on based on what time of year it is and what the house temp is...but at least one is on all the time. This allows me to maintain the temps I mentioned in my earlier post.To get the humidity where I wanted it I set the tank up as follows: The bottom level of my tank is 1/2 forest bedding (which I keep pretty moist and the PPs just love) and the other half is slightly moist sand (which the Es and Straws seem to prefer). Plus I have a salt water pool that is about 6X4 inches. My second level, which is made of plexiglass (about 16 inches long and 12 inches wide) and holds about 3/4 inch of substrate, holds a medium fresh water bowl (putting it on the second level,closer to the light allows for good evapoartion for the upper levels), and a subtrate that is a forrest bedding/sand misture on one side and calcium sand on the other. My third level (which is only a couple inches from the top of the tank) is an upside down turtle dock, in which I have forrest bedding and moss which I keep really moist (my Es and Straws love to hang out up there). In addition to this, I have a humidifier that comes on from 1-3 in both the am and pm hours (its on a timer).It took a couple weeks worth of trying to get the heat and humidity balance just right, but once I found the magic "balance" it has been very easy to maintain...and like I mentioned, seems to allow for the different gradients that the diferent species likes.

Guest · Post by **Guest** » Fri Jun 10, 2005 12:44 am

Oh - one thing I didn't mention, for the red lights, the 15 watt is one one side of the hood and the 25 watt is on the other side of the hood. As I mentioned, the straws love to bask under these....So much that if you turn one off and turn the other on, you can see them move from their favorite spots on the one side of the tank to thier favorite spots on the other side of the tank just to be near the light! My one straws in particular will do ANYTHING to get as close to the light as possible! (They are amazing climbers!). Having the straws and noticing how they love to bask (as well as the E's) is why I am a proponate for overhead lighting...if you have a tank that is big enough. Now my PP's don't give a hoot if I have the red lights in there for basking or not! So if I just had them, don't know if I would bother with the red lights!

Hercule · Post by **Hercule** » Fri Jun 10, 2005 11:10 am

Yeah, I noticed that my crabs really liked the heat when I had their 55 gallon out on the porch. I had never seen them so active before, I was amazed. The temp might have been to high though, with an average of 85-95.

Guest · Post by **Guest** » Mon Jun 13, 2005 8:10 am

It has been so warm here in Chicago the past couple of weeks (I'm talking over 90 almost every day) and my tank has been in the mid 80's, with the humidity in the same range. They have been very happy with it and seem really active and comfortable! I sort of got the hint last month as it was warming up... on nice warm days I have taken the hermies in the backyard to play in a big huge tupperware storage container and they went bananas playing around! I'm wondering if they are okay with it a tad warmer than we have thought (but then there's always that bacteria issue...)