Humidity - Experienced keepers welcome...

[Cirith Ungol]

Since last time this topic has been chewed through there have been some questions on my mind which I'd have liked to discuss here. Please refrain from answering if you don't have years of personal experience with keeping Ts.
Why another humidity thread? Because I hope to gather the ultimate answers on the topic this time (Too ambitious I know, but I wanna try! )

Plunging right in:

If using bonedry substrate does the air have to be humid instead? Or is the air equally bonedry?

For arboreals - do the same rules as above apply for both air and substrate?

What should the difference between air and ground humidity be for diggers? Can diggers do their exavations in bonedry substrate (lets say in peat)?

Have there been some deaths that are clearly related to bad moults because of dry conditions?

Slings: Substrate moisture vs. air humidity what's the difference?

That arboreals and slings do drink from water droplets and that every T should have a full waterdish is clear, so there is no real need to adress that.

 

[Dr Pies]

Hi Cirith,

I have just spent the last 2 hours changing substrate on my whole T collection thanks to having the substrate too damp.. I got mites.

I am now going to keep all substrate bone dry except for the waterdish area, as I dont think its neccessary..
Anyway...
Bonedry substrate is fine in my opinion as long as there is a wide water bowl provided, this will keep the air humidity up as opposed to the ground humity, which is pointless.
For the diggers I prod a hole into the substrate and pour water down deep,then if they decide to burrow, it will be nice and humid for them. I think some people have used a syringe for this.
I have had one T die in a moult situation, but that was because it was a sling and I was stupid enough not to mist..
For my arboreals I mist the sides of the tank and thats it.. They get there moisture from their food, and I have never had a problem.

Sorry if this answer sucks, I'm knackered with moving tanks around..

 

[Michael Jacobi]

I could write extensively on this subject, which sees much debate, dissention and misunderstanding, but I don't have the time so I will just make some basic points.

First, hobbyists tend to define humidity different ways. Technically, relative humidity is a measure of the amount of water vapor in the air. The amount of water the air can hold is directly related to air temperature. In short, if air is gradually cooled while maintaining the same level of moisture, the relative humidity will rise until it reaches 100%.

Humidity does not mean stagnant air. Even animals who live in the most humid forests with high levels of precipitation are exposed to fluctuations in humidity and circulating air. I recommend erring on the side of dryness with greater ventilation than erring on the side of dampness - often the result of poor ventilation. Captive conditions are usually much more static than those in the wild - in other words, conditions change day to day naturally, but some keepers force captive animals to adapt to a narrow range of temperature and humidity.

The most natural way to provide humidity is through evaporation. That is, a large shallow water bowl that evaporates into the surrounding air. I often overfill bowls to remoisten the surrounding substrate, but at the same time provide excellent ventilation and a drier side of the cage. Just like temperature/heat should be provided in a manner that allows ectothermic animals to thermoregulate, substrate moisture should vary from one end of the cage to the other so that an animal can move from areas of moisture to dryness and vice versa as needed.

Regarding humidity levels for burrowing species, a burrow is not only cooler than the air at ground level and above, but is also more humid [see discussion of relative humidity as it relates to temperature above. If you house burrowing species from humid habitats [like many Asian tarantulas] properly they will have sufficient humidity levels without excessive dampness. (See Martin Huber's housing in a thread elsewhere - I don't have the link handy or time to search).

An essential part of tarantula husbandry is having fresh water available to all specimens large enough to not drown in a small dish. Once a spider has a legspan larger than a 2-liter soda bottle cap I use the cap as a dish and use appropriately larger dishes with increase in spider size. In the case of arboreal species this water dish should be elevated. Using aquarium-safe silicone or hot glue to affix a double 2-3 oz. condiment cup [one as holder, one as dish] 2/3 up the height of the vivarium is what I recommend.

As for molting tarantulas, yes dry conditions can kill even species from xeric climates during the molting process. I recommend feeding these "desert" species often so that they are well hydrated without dampness surrounding them. For example, a xeric climate species spiderling such as Chromatopelma cyaneopubescens will molt fine kept "bone dry" if well fed, but if it hasn't fed recently and is therefore dehydrated it may very well expire during the molt.

I won't comment much on misting here. Keepers tend to be strongly against or strongly for this practice with little middle ground. I will say that I do mist the vivaria housing my arboreal tarantulas as needed based on room humidity and outside air humidity. I also use cool mist humidifiers as needed. I think part of the reason misting gets a bad rap is that people do so in improperly ventilated cages and create problems associated with dampness. My cages are ventilated well and even after a heavy simulated rain the cages will be dry by morning. In other words, different situations require different methods. VENTILATE WELL!

That's it for now... You'll have to wait for my article on this subject in the July 2005 issue of 'ARACHNOCULTURE' for more

Cheers,

Michael

PS: Experience does not equal knowledge, which cannot be measured in years. Some people do something wrong for their entire lives. Others, learn from someone experienced and/or with a thirst for knowledge and become great keepers in a short amount of time. Numbers don't mean much. That said, I hope my 32 years keeping tarantulas qualifies me

 

[Windchaser]

I have had my T's going on 5 years now. So, I hope that qualifies. Anyway, I have not done anything special with respect to humidity. They pretty much are in the same conditions as my house. I do use humidifers during the winter months, but more for my comfort than for the T's. I have my humidifiers set to 35%. I imagine the overall level in the house is between 35% and 40%. When I setup an enclosure, I will dampen the substrate (100% peat) at that time. This is mainly to cut down on the dust while I am messing with it. After that, I usually just let the substrate dry out. When I fill the water dishes, I will occassionally let some water spill over. Beyond that, I don't do anything else. I never mist my enclosures. To date, I have not experienced any problems with any molts.

For small s'lings, I also try to keep the substrate dry, since it cuts down the chances of mold. Since they are too small for water dishes, I will put a few drops of water in the vials about once a week. I try to get it on the sides so the T will have some droplets to drink from. I haven't really been having problems with any of my s'lings either. The exception is a couple of G. rosea s'lings that aren't eating. However, these are only a couple out of an egg sac and are likely weak spiderlings. All the others are doing great under the same conditions.

None of my burrowers have seemed to have any problems with the dry substrate.

I haven't had arboreals long enough to comment. However, I have been keeping my P. regalis s'ling under similar conditions and it seems to be doing very well.

 

[Sheri]

If using bonedry substrate does the air have to be humid instead? Or is the air equally bonedry?

The air can be dry but this will see your water dish evaporate quickly, every 2 days or so if you are using a centralized dry heat source. (like a furnace)

For arboreals - do the same rules as above apply for both air and substrate?

Techinically yes, though some people have experienced some issues with avic (that I have read) with the spider being unable to find the water dish. I have seen all my spiders drink from a water dish at one point or another that were large enough to do so, with exception of my avic. Not saying it doesn't happen, just that I haven't seen it. So I tend to mist around its web retreat.

What should the difference between air and ground humidity be for diggers? Can diggers do their exavations in bonedry substrate (lets say in peat)?

I have no idea if they can burrow in 100% bonedry peat. I typically use a mix of organic soil and peat, which works just fine. I usually use something artificial to begin a burrow with. My P. murinus burrows and it is kept totally dry. My lividum, not as dry. I will overfill the waterdish from time to time.

Have there been some deaths that are clearly related to bad moults because of dry conditions?

Yes, I have experienced this with species reputed to be more moisture dependant but only during the winter time when my house is very dry. This has occured to one mature WC E. murinus, T. apophysis sling, M. robustum, and a sub-adult X. intermedia.

Slings: Substrate moisture vs. air humidity what's the difference?

Are you asking which is better?

Essentially, pay attention. Spiders don't have a steady, clean waterdish in the wild and are forced, as a result, to rely on the environment to provide hydration. I have had specimens that do not seem capable of consistently walking 18" to the other side of the enclosure to find water. Those ones gfet two water dishes and are monitored frequently.
Slings without a waterdish need misting. I don't think you can stick to one method entirely. You need to adjust slightly not because of what a care sheet tells you, but because you know your animals.

 

[Cirith Ungol]

I want to thank you who have answered so far!

The topic of humidity can seem to be easily solved when one wants to, by sticking a finger into the substrate and nodding agreeingly. It can also seem very complex and almost a bit hard to predict, as SpiderShoppe points out so clearly. I guess that the question about humidity is often solved in a way of personal preference. My preference is that I want to learn as much as possible about it and to use that knowlage to the best of my abilities.

The one thing that stands out to me is that humidity, in combination with airflow and temperature surely must be one of the most complex issues of keeping Ts. I for one am guilty of underestimating the complexity of that issue.

That said I want to clarify for any new hobbyist who happens to read this that a basic good environment is easy to keep. It is the fine tuning that needs good consideration and a bit more thought.

Experience does not equal knowledge, which cannot be measured in years. Some people do something wrong for their entire lives. Others, learn from someone experienced and/or with a thirst for knowledge and become great keepers in a short amount of time. Numbers don't mean much.

I agree fully. My thought was to try to include the time factor in order to reach keepers which have experienced a few moults, in addition to seeing the various changes of their tanks environments over a long period.

 

[Washout]

I've been pretty successful raising my slings so far. I've had two deaths due to dessication. In both cases they were in very small deli cups with a lot of holes and not enough dirt. I simply make sure that the dirt never drys out all the way, if it starts to get close then I wet it down again. However they are kept in a tempature and humidity controlled room. I keep a bucket of water near the heater and the humidity stays right close to 40% at all times.

So far I've successfully raised P. irminia, P. regalis, B. albopilosium, B. smithi, and A. versicolor from slings to juvies, and I don't mist. Up and coming is some GBB's, H. maculata, P. formosa and more P. regalis.

Also I've found the easiest way to feed is to give the sling a slightly overlarge container and then drop in 4 or 5 food items at a time. Even if they are close to a molt they have usually constructed a nice hide away so the crickets can't get to them.

Right now I have around 80 or 90 slings and 30 adults and juvies.

 

[Kid Dragon]

Rule #1 Error slightly to the dry side.

Rule #2 If you can't resist daily watering, you better have great ventilation.

Rule #3 A full water bowl can provide enough humidity for many species.

Rule #4 If you have poor ventilation and high humidity, expect fungi and mites

Rule #5 Don't stress over humidity.

For example, I fill the water dish (bolted near top of container) for my A.versicolor once per week. I overflow it slightly every other week. I don't measure humidity.

 

[Blasphemy]

There seems to be a big stress on ventilation. I'm just wondering if you're keeping your T in an aquarium, if a screen top is all the ventilation it needs or if there's other methods?

I have also combed through some of the many other humidity threads, and I haven't heard a mention of sphagnum moss to keep humidity up... I would think that moss would be great for tropical species who need a boost of humidity and that way you won't have to even worry about slightly damp soil or misting. Just a thought.

 

[monster_bugs]

i hear a lot about T.blondi slings dying for "no apperent" reason, and that they need constant humidity and damp substrate, and i recently got a 2 inch blondi which molted and is now i guess around 2 3/4 and im stuck in the middle of 2 fires.. on one side i hear ppl saying to keep blondis damp, and on the other hand i get mites in her tank and i noticed some on her body.. on some joins and chellicerae.. i really am not comfortable with mites and id love t oget rid of em, so do u guys think its safe to keep her on bone dry substrate with a full water dish at all times? and can the mites taht are on her cause any harm(white tiny mites)? and is there any effective way to get rid of them that you have used? thanks in advance

Igor

Igor

 

[shogun804]

its hard to say for me ive never kept T blondi but i would suspect that from what ive read they need it generally humid which means air humidity not damp substrate IMO get a large waterbowl and keep it filled, put some rocks in etc just in case crix decide to go in there ...if i were to keep them that is what i would do. and the mites sorry i wish i could help but i have yet to come to that bump in the road with any of my T's

 

[Lopez]

Personally, I prefer not to err on the dry side.

This is due mainly to the fact that none of my spiders have a water dish of any sort. Actually, I tell a lie - my old G rosea has a dish and dry substrate, and any freshly imported wild caught spiders get a dish for a while. I feed regularly, probably more regularly than most with large collections, to offset the lack of fresh water.

I keep only arboreals and fossorials, aside from a handful of terrestrial species, so water dishes are not particularly practical anyway.

This is how I keep my burrowing spiders.

Deep tank, lots of substrate. Substrate is soaked periodically, typically 2 or 3 times a year. By soaked I mean placed in a bucket of water (or, if doing several tanks, a bath full) for some hours. Mostly the spiders stay underwater, but some surface and sit at the top of the tank. Then I remove the tanks and allow to drain for a few hours. This leaves the substrate soaked but not sodden. For some months humidity inside the burrow remains sufficient to see small beads of moisture on the walls in the evenings. The top layer of earth above the burrow can become dry within a few days - I spray this lightly and periodically to prevent the peat turning "dusty".

During these wet periods, the tanks are wet enough to grow a fine but definite coating of algae or moss on the inside walls of the burrow (pers. comm., vonWirth)
This is the level of moisture I aim to maintain most of the time.
The tanks dry out naturally over the course of a few months, by which time they are ready to be watered again.

I use a similar technique for arboreals - just less substrate.

I'm not saying it's perfect, I'm not saying I'm an expert, I'm not saying you should do the same as I do, but it works for me, and it's the closest I think I can get to replicating natural subterannean conditions for my Asian burrowers.

 

[Schlyne]

Can diggers do their exavations in bonedry substrate (lets say in peat)?

Well, both species I'm going to list are probably better defined as semi arboreal, but they can dig without a problem.

I rehoused an E. murius sling for the second time to combat a mold problem (along with adding more ventilation), and it has created a typical tall, volcano like burrow in bonedry substrate. (It's misted, it's too small for a water dish).

My P. Irmina juvie has created a tent web with the substrate against the cork bark, and excavated some of the substrate so it can hide at the bottom of the container. It did this in bone dry substrate as well.

EDIT: On second thought, my Chaco dug a burrow in bone dry substrate. However, it wasn't very deep.

 

[arachnojunkie]

Can diggers do their exavations in bonedry substrate (lets say in peat)?

I think that depends on the individual. For example, my A seemani will burrow all day with bone dry 100%peat, on the other hand my C crawshayi will dig a hole in the back corner of the tank, web it up and never dig again, that is, until I pour water into the previously dug hole, by the time the water soaks in she almost instantly starts an amazing looking burrow.

 

[Apocalypstick]

My gulchie will "milk" DRY substrate into balls and build with them. She seems to like this method of closing up her DRY coconut burrow. Then she will web to these milked barriers and the glass side , as well as her coconut. When she wants to come out or is hungry, she removes a ball at her hide opening and builds a thin web to come and go through.... for water and food.

She is so creative

 

[MizM]

I've lost too many Ts to nematodes... dry is better. When I was a newbie, I used the old hygrometer and thermometer and tried desperately to keep things just as the care sheet said. I had mold, mites, phorid flies, scuttle flies and nematodes. I learned very quickly that if a T needs water, a full water dish will suffice. Again, moisture dependant species such as T. blondi must be kept a bit wetter, but pill bugs in the enclosure and plenty of ventilation prevents problems.

My burrowers on the other hand, are kept in tall containers with holes on the bottom as well as the top. I use the soaking method mentioned above and have had no problems.

 

[SergioCR]

Question about ventillation

Hi, i was wondering how to make the right ventillation on a plastic cage (microwave transparent plastic holder) that i'm using to keep an small tarantula i found, i have made about 30 holes at top separated about 1" between and they are about 3 to 4mm diameter but it seems that i have some water condensation at the sidewalls (underground and a little above the ground level)

Should i drill another set of holes (for a total of 60 holes) or what can i do to lower humidity inside?

The tarantula it's from my backyard (located in Costa Rica)

Photos can be found here: Small Tarantula found at backyard

 

[arachnojunkie]

Congratulations on the find, you are very lucky to live in a place where tarantulas are common. As far as the condensation goes, are you misting, is the substrate wet as it is being put in, what kind of substrate are you using? 30 holes seems like it would be enough unless you are intentionally keeping the enclosure wet. If the spider is still under 3" the condensation should be fine and IMO is normal so long as it isn't a pond in there. If the spider is over 3", change substrate to bone dry peat and/or organic soil, and supply it with a water dish. This should solve all of your problems......I think.

Matt

 

[Windchaser]

Hi, i was wondering how to make the right ventillation on a plastic cage (microwave transparent plastic holder) that i'm using to keep an small tarantula i found, i have made about 30 holes at top separated about 1" between and they are about 3 to 4mm diameter but it seems that i have some water condensation at the sidewalls (underground and a little above the ground level)

Should i drill another set of holes (for a total of 60 holes) or what can i do to lower humidity inside?

The tarantula it's from my backyard (located in Costa Rica)

Photos can be found here: Small Tarantula found at backyard

I would add more holes for additional ventilation. You are in a fairly humid place to begin with, so I don't think you really need to worry much about increasing humidity. If you enclosure has condensation, then you are inviting mold, mite and fungus outbreaks.

 

[JJJoshua]

I've never really worried about humidity. I use bone dry with every T, with the exception of some OW T's. I don't think that humidity has much, or anything to do with bad molts. It's not the amount of moisture outside the spider, but inside. My smithis molt on bone dry all the time. I usually see them drinking a lot before the molt though. Same with my blondi, once I forgot to water her for 2 days and just so happened she was going to molt, it wasn't a terrible molt but she had trouble getting herself out of her abdomen and ended up with a blister-like bump on her ab. I feel that so long as the T has an adequate water supply they will do fine.

I did find that even though my T had water, it didn't seem like it knew there was water. They would hide in their burrow and the water would just dry up. So tried misting, and getting some water actually on the T, and after they settled down from being wet, I noticed that night they would venture out to the water bowl for about an hour or more and then move back into their hide.

For T's to molt correctly they need to produce enough exuvial (sp?) fluid in order to seperate the old skin from the new. So if the T isn't drinking enough water or getting enough food, their molt may be troublesome, due to a lack of adequate exuvial fluid. This is why I usually mist every two or three days, to kind of simulate a rain, this way the T can understand that if it just 'rained' that water is out there somewhere.

With my OW T's that burrow like my lividum and murinus I mist a lot more. More so to coax them out of their deep homes they have dug and therefore I need to mist them more to get the same effect as with my non-burrowing T's. This just so happens to up their humidity. But my lividum did molt successfully on bonedry substrate, no prob.

I think the only time humidity matters is with slings. They're small and still developing and need as much from their environment as possible. Since they're so small they can only hold a little amount of moisture in their body and must replenish it as often as possible. This may be why some blondi slings die unexpectedly. They're so small that they dessicate so fast and even a brief time of low/no moisture can deplete them of water.

IMO, I've never had a problem with low humidity and I do not mist a lot, usually not enough to dampen the substrate just enough to let the T know.