Humidity, Temperature, and Tarantulas

We’ve all done it.

After hours of exhaustive research in which we read about a tarantula’s natural habitat and peruse a plethora of care sheets (many of them with conflicting information), we set up what we hope will be the “ideal” habitat for our new pet. We add the appropriate substrate, a cork hide, a water dish, maybe a plant or two, before introducing our new pet to his “perfect” home. All is well for a night or two..

And then the stress begins, as we obsess about keeping temperatures and humidity at the optimal level for this species. The care sheet said 75% humidity, but the $8 ZooMed hydrometer I picked up at Petco says it’s only 60%. Time to spray down the substrate until it’s a muddy slurry, right? Or, the temperature in my house just dipped to 68º, so I’d better put a heat lamp or mat on my critter, correct?

The short answer to both of these questions, in most instances, is a very emphatic NO.

Tarantulas are not as fragile as we make them out to be.

One very important thing to keep in mind when working with tarantulas; they are very adaptive animals. You don’t survive millions of years of evolution and climate change without being able to tolerate a dip in temperature or a bit less humidity. It’s true that some species have evolved over the centuries to adapt to different ends of the climate spectrum. Sure, a T. strimi is accustomed to living in humid conditions that would likely kill an arid species like a P. murinus. However, in between these two extremes, there is a lot of gray area and quite a large margin for error when correctly controlling the environment of your tarantula.

Now, I’m not saying that we want to keep our pets in less than comfortable conditions just to make it easier for the keepers. It’s still important to acknowledge the difference between “comfortable” and “tolerable.” It’s just very important to keep in mind that the high and low temps present in a tarantula’s natural habitat may not not represent the ideal temps for the T.

For example, consider the M. balfouri. On the island of Socotra, high temps can be in the high 90s with low temps around the low 60s. That’s a huge range, about 30º, and neither the high nor low temperatures there would make for a particularly comfortable spider. Therefore, a keeper trying to keep these exact highs and lows would be seriously missing the mark. Yet, some keepers will still obsess over keeping these highs and lows in their home setups.

Burrows = The “X” factor.

We also tend to forget that many tarantula species live in burrows and some dig them deep into the earth. This allows the spiders to escape hostile environments and to seek more humidity (or less) when needed. Temperature and humidity measurements from within tarantula burrows in the wild reveal the climates inside are much different than the outside climates. Considering that many species spend the majority of their time inside their burrows, this would mean that we actually have NO idea what the ideal humidity and temperature levels are for many of these species.

So, what do we take from this? Well, first off, it means that the temperature and humidity “requirements” included on many care sheets are next to useless and that the stress you get from not matching these numbers in your setup is also unnecessary. If you are obsessing over either, you are making the hobby more stressful than it should be.

Normal “room temperature” is okay for most species.

I hear this said on the forums all of the time, and it is a good, if slightly too vague, rule of thumb. For most folks, their normal room temperatures will be sufficient for the majority of species of tarantulas. Generally, if you’re comfortable, then your tarantula will be comfortable, too.

My all-purpose thermometer/hygrometer.

My all-purpose thermometer/hygrometer.

That being said, this rule causes confusion as normal “room temperatures” may vary from home to home. For example, in my house, we like it a bit cooler than most, so my living room at the moment is about 64º. My grandmother, on the other hand, likes it toasty, and her home is around 88º this time of year. Both of these temperatures represent extremes, and some species of Ts kept for long at either end could experience distress.

Therefore, a modicum of common sense is needed when applying this rule. If you’re cuddled up in several sweatshirts and a blanket to watch TV, then this is not a comfortable room temperature for your animals. Conversely, if it’s summer and the 89º heat in your home has your sweaty clothes sticking your body like blistered layers of skin, your Ts are not going to be happy.

The majority of the species will do well in a temperature range between high 60s and mid 80s, and will tolerate temps slightly higher and lower than these for shorter durations. If your home is 67-70º throughout the winter, you don’t have to worry about procuring some sort of alternative heat source or else risk your tarantulas dying. They may not eat as much or grow as fast (warmer temps lead to faster metabolisms) but they will be just fine.

If you should decide that you need supplementary heat…

I’ve read posts by hobbyist who live in drafty houses where the temps consistently get lower than would be appropriate. Or, there are folks like myself who have a room dedicated to raising these animals, and they purposely want to keep temperatures higher to promote growth or breeding. In these instances, it is always best to control the overall temperature of the room and not the individual enclosures.

The space heater I use in my tarantula room.

The space heater I use in my tarantula room.

The best heating option for situations like these is a space heater. There are many types available on the market, including oscillating heating fans and oil-filled electric space heaters. Most also come with built in digital thermostats and timers, allowing for you to create an optimal day/night cycle. If you do go this route, be sure to do your research and look up reviews to get the best, safest heater for your money.

And if you do decide to go with supplementary heating, please remember the following:

  • No heat mats!
  • No heat pads!
  • No heat rocks!
  • Absolutely NO Heat lamps!

Most pet store heat mats, heat pads, and heat rocks are not appropriate heating sources for tarantulas. All three can create hot spots that can injure, dehydrate, and kill a T.

That said, there are some folks that use heat mats combined with rheostats to heat their collections, but doing so takes some experimentation and finesse. If you absolutely can’t use a space heater and feel that heat mats might be a better fit, do some research and speak to keepers who have experience with these setups. Most who use them heat larger areas, like tanks or cabinets, then put the T enclosures into these. Heating individual tanks is much more tricky and risky.

Heat lamps are very dangerous and can dry out and kill a tarantula very quickly. I don’t care how many thermostats and temperature-regulating gadgets the pet industry sells, these heating sources are likely to do more harm than good.

Humidity … Stop Worrying!

NO-HYGROMETERThe anxiety created by dreaded “H” word is likely a leading cause of stress-induced hypertension in new hobbyists. All joking aside, the humidity “requirements” listed in many care sheets have created a massive issue where none should exist. Too many times, a new hobbyist will read some arbitrary humidity level on a care sheet, rush to Petco to pick up one of their cheap, inaccurate (read: USELESS) humidity gauges, then panic when they can’t hit that magic moisture number. This is a waste of time, energy, and stress that can better be spent on sports teams, money, and taxes.

It’s important to keep a few things in mind before obsessing about humidity.

  • Accurate humidity levels are almost impossible to measure with cheap, over-the-counter humidity gauges. In other words, if you’re obsessing over the number on your Zoo Med hygrometer, you are likely stressing over an inaccurate measurement.
  • Humidity requirements listed on care sheets often don’t take into account that humidity levels differ from region to region. If you live in an area with high-humidity naturally, like Florida, and you are misting down your avic, you are likely doing much more harm than good. Always take into account local climate conditions when setting up your enclosures.
  • Most species are able to thrive at many different humidity levels. Even genera like Avicularia, Poecilotheria, and Lasiodora, once thought to need much higher humidity levels, have demonstrated the ability to do very well at lower humidity levels when supplied with water dishes. In fact, some keepers now attribute many Avicularia deaths to overly-humid, stuffy enclosures.
  • Humidity levels in properly vented enclosures are often much different from those in the homes they are in. The humidity gauge in your home may read 45% humidity, but the moisture level in your enclosure may be much higher. If you go spraying the cage down, you might be raising the humidity to dangerous levels. Overly moist enclosures are a death trap.

The fact is, most species do very well in a cage that allows for proper cross ventilation (holes in the sides, not the top) and a water dish. That’s it. For asian species, using deep, moist substrate and supplying a water dish is all that they need. They will construct burrows beneath the sub which will provide the correct humidity level for them.

Now, are there situations where you should keep an eye on moisture and humidity? Certainly. I live in New England where the winters can be cold and my home’s furnace may be running for weeks at a time. This dries the air in my home, often resulting in humidity levels in the teens. In these instances, it makes sense to run a humidifier to keep levels at a safer level (I usually opt for about 40-50%).

Slings are also more susceptible to dehydration, so many folks choose to keep all spiderlings on moist substrate with good ventilation. Slings around .75″ can also be given water bowls, which also aids in preventing them from drying out. For my tiniest slings, I keep the substrate slightly moist on the bottom, then offer sphagnum moss on the top, which I keep moist for drinking.

With proper enclosures and husbandry, humidity level should never be a factor, even if outside conditions seem less than optimal. Here are some husbandry tips that will keep you from every having to fret about humidity.

1. Keep a water dish filled with fresh water at all times.

The easiest way to keep the humidity up in an enclosure is to add a water dish. A large, open dish will allow water to slowly evaporate, raising the humidity inside the enclosure as long as it isn’t overly vented. It will also, obviously, serve as a drinking source for a parched T. For some species, like my T. strimi, I will even include two dishes.

2. Restrict ventilation.

Are you using a screen top on your aquarium, or is your T housed in a critter keeper-type enclosure? Both of these cages will allow for too much airflow and rapid evaporation, which will inhibit you from creating a “micro climate” inside the cage. A good enclosure should offer cross ventilation (holes/vents should be on the sides) and airflow, but should also prevent conditions inside the cage from becoming too dry. You must be careful not to restrict airflow too much, though, as not enough ventilation will create a stuffy, dangerous environment.

3. Use moist soil for tropical or Asian species.

For species that appreciate a little extra moisture, I use moist, not wet, substrate. My go-to mixture for these enclosures is topsoil combined with a bit of peat moss with some vermiculite mixed in for moisture retention. It’s moist enough that it will stay together when squeezed without water wringing out of it. My O. philippinus, P. cancerides, C. discolus, P. antinous, H. gigas, and T. stirmi are all kept on topsoil mixed with some vermiculite to maintain moisture. When the levels in my room are too low, they can retreat to their dens for a more humid environment.

4. Provide enough substrate depth for burrowing.

Many keepers opt to keep Ts on shallow substrate so that they can see them out more. Although this is obviously up to the keeper’s discretion, and most species will easily adapt, it will prevent some animals from burrowing to find more suitable conditions. When in doubt, it doesn’t hurt to give the T extra depth in which to dig. Even for species that don’t dig, the extra depth will allow the bottom levels to remain moist while the top remains dry. As this trapped moisture slowly evaporates, it will elevate the humidity in the enclosure.

5. Don’t spray … make it rain.

An old juice bottle modified with some holes to be a watering bottle.

An old juice bottle modified with some holes to be a watering bottle.

Many hobbyists talk about spraying water into their enclosures to increase humidity. This technique only raises levels for a short period as the surface liquid quickly evaporates. When I want to add moisture to an enclosure, I like to “make it rain.” Using a soldering iron, I put several holes in the top of a large juice bottle and turned it into a handy watering pot. Instead of spraying water into the enclosure, I simulate a downpour and soak down one side. The moisture eventually sinks in, keeping the sub moist as the top dries up.

6. Use a humidifier.

If you live in a region with cold winters, necessitating that you use a furnace, chimney, or wood stove to heat your home, chances are that the humidity levels will get dangerously low. In these instances, even properly set up cages can dry out quickly. The best solution to this is to purchase a humidifier. You don’t need to overdo it if you go this route; a humidity level between 40 and 50% will suffice.

Don’t let needlessly worrying about temperature and humidity add stress to the hobby.

For the majority of the species available, and for all of the tarantulas I named in my Beginner Tarantula guide, room temperature and humidity will be fine. In my opinion, there is NO need to purchase a humidity gauge, as they are woefully inaccurate, and in most instances, supplementary heat is also unwarranted (and sometimes dangerous).

Is there a time where more careful, species-specific micro-climates are necessary? Yes, as those looking to breed species, especially some of the more difficult ones, will look to recreate natural environmental triggers, like high temps, winter lows, or wet seasons to stimulate a mating response. In these cases, some careful management of their tarantulas’ micro-climates will be warranted. However, for the casual keeper or for one new to the hobby, this should never be an issue.

So toss those humidity gauges and heat mats in the closet, leave the spray bottle for the plants, and stop worrying about temperature an humidity. Your Ts will appreciate it.

Advertisements

20 thoughts on “Humidity, Temperature, and Tarantulas

  1. Hello tom

    Im purchasing a female fringed ornamental tarantula im sort of familiar on housing it but can you give more information please with your knowledge. I’ve got a lasiodora parahybana where the care sheet is totally different.. thank you

    Like

    • Hi, Bilal!

      I actually just purchased a female P. ornata myself, and I’m eagerly waiting for its arrival (the cold temps and snow here have not been conducive to shipping spiders!).

      I keep several species of pokies, and I’ve found that all of mine are thriving in similar setups. In the past, people tended to keep this genus in a very warm and humid environment, with wet substrate and constant misting. I tend to follow the trend of drier enclosures (mostly dry/slightly moist substrate) with water dishes. I offer cross ventilation (holes on the sides of the enclosure to allow air to pass through), and don’t constantly spray or moisten the substrate, letting it occasionally dry out a bit in between so that it isn’t to stuffy.

      For small slings, I WILL dampen a corner of the substrate, keeping the rest mostly dry. I’ll also sprinkle some water on edges of the enclosure and on the leaf of the plastic plants once a week to give it a drink. Once they are over 1.25″ or so, I give them a small bottle cap as a water bowl.

      At 2.5-3″ I give them a much larger waterbowl (about 3″ in diameter) and only moisten the substrate once or twice a month (or weekly when they are in premolt). When I do, I make it rain in a corner, then let it dry out a bit in between.

      In the winter, mine are kept about 72 degrees at night and 78 degrees during the day. Despite the slightly cooler temps (most care sheets will tell you 80s) all have been thriving, with my smaller ones having molted three times over the past four months. They can obviously be kept warmer, and this would likely lead to faster metabolism and growth, but I think that they are quite hardy and adaptable to environments that don’t necessarily replicate their natural habitat.

      For enclosures, I like to give them a bit of extra room because they are quite fast and can pack a wallop of a bite. This gives me some room in which to work when I have to perform maintenance.

      All of my pokies are GREAT eaters, and they will take prey items right up until they molt. I also find that they are able to subdue larger prey than some of my other species. I usually start feeding them large crickets when they are at 3″ or so.

      What did the care sheet for the L. parahybana say?

      Let me know if I can help with anything else. Again, this is what works for me.

      Tom

      Like

  2. Hi Tom,

    First of all, great blog! Thank you for all the useful information.

    I have my first T, a B. albopilosum, and I am wondering about the humidity of the substrate. She is in her 5th or 6th molt and about 1.25″ big (body length). The guy I got her from send some substrate and a little plastic container with her that I could use the first days. I immediately noticed that the substrate was quite damp (I think it was peat moss). As I put her in her enclosure with the provided substrate she immediately showed her landscape artist skills (as I think comes with the species) and she happily bulldozed away. She was a bit skittish at first, kicking hairs, but I also noticed that she got the substrate out of her way and she preferred to sit on her hideout or on the bare plastic of the container bottom so I thought the substrate was too humid after all.

    I put her in a bigger enclosure (small critter box) with eco-earth, a lot drier than what she had, but not bone dry. She was clinging to the walls the most time so I replaced it with really dry eco-earth.

    She has been eating (but not ferociously), she is drinking (small bottle cap), but she is not really doing much. No digging, or rearranging the substrate, nothing. Compared to how she was in the beginning she seems a bit lethargic.

    Of course I am a typical T-noob, probably fuzzing too much about everything. But better safe than sorry: am I doing something wrong? Is the substrate too dry? Could it be anything else?

    Thank you very much!

    Sas

    Like

    • Hi, Sas!

      You’re most welcome! I’m just glad that people find this stuff useful. 🙂

      First off, was the substrate coco fiber (Eco-earth) that he sent? Coco fiber comes in dry, compacted brick that must be soaked in water to loosen up the substrate to make it usable. For species that need it damp, this is great. For arid species, you have to either let the coco fiber dry out for a week or so, or carefully heat it in the oven on low heat for a bit to get the water to evaporate. If it’s coco, it’s likely that he just grabbed up some of the moist stuff and packed it up.

      When tarantulas climbed the walls of the enclosure, it can mean that the substrate is to moist. They are essentially trying to escape it. You definitely did the right thing by replacing it with dry eco-earth.

      If you have provided her with a water bowl, that should be enough for her. You could always let it overflow a bit in the corner, but she really should’t need that. An albopilosum that that size is a juvenile and should not need extra humidity.

      She could be less active because she’s more comfortable (her digging might have been a way for her to escape the moist sub). I have also had Ts wait a few months after being rehoused to burrow.

      Has she molted in your care yet? Is it possible that she’s in premolt? If she seems lathargic, that could be a possibility as well (although, if she’s still eating, that’s likely not the case). Doe she have a hide?

      Tom

      Like

      • Thanks for your advice! The substrate that came with the spider looked different than the eco-earth that I am using. It was less fibrous and could well have been potting soil. So I have no idea why he send it with the spider.

        To dry the eco-earth I put it in the oven, just as you wrote on your blog. I think she is more calm now and I am glad to hear that the fact she is not digging does not mean anything per se. She is now sitting in an indentation in the substrate that I made for her so she is fine with the substrate as it is.

        It crossed my mind that she could be in pre-molt, but I do not think this is the case. Her colour did not change and she is indeed eating.

        It is such an interesting creature and even my wife is fascinated by it (it really took a lot of convincing to get her to agree to having a tarantula). She even agreed to get more than just one! So, the albopilosum seems just the beginning of a collection of spiders 🙂

        Like

      • Hi, Sas!

        Ah, yes…potting soil. It’s funny; a while back I purchased some slings from an exotic pet store, and I couldn’t figure out what substrate they had used. I finally called and asked…potting soil!

        Sounds to me like you are dong all the right things! Calm can be good, especially for a species like this that is recognized for being even-tempered. I do know what it’s like, however, to see a spider suddenly change its habit or temperament. It make you worry that something is up. Those are the types of good behavioral observations that will help you to recognize when something might be wrong, though, so all is good.

        That is fantastic to hear that your wife has learned to appreciate your tarantula (and that she’s even agreed to more!). I’m very fortunate that my wife has been VERY understanding as well, even as my collection went from one to 90+!

        Now, just be careful…this is a VERY addictive hobby! You’ve been warned… 😉

        All the best!

        Tom

        Like

  3. Thanks for the heads up! 😉 I will bear in mind that it is an addictive hobby (and I will NOT tell my wife yet!).

    My albopilosum is very calm indeed, walking around in the enclosure a bit but mostly sitting in a corner. She has not been eating for a few days, but I decided not to worry too much.

    Thanks for all your advice!

    Sas

    Like

  4. Update: my B. albopilosum changed her appearance a little. She is much darker and her abdomen look like a ripe blue grape. I guess the change in her behaviour had something to do with her being in pre-molt. I am very much looking forward to her molting. Such interesting creatures!

    Sas

    Like

    • Hi, Sas.

      Yup, that sure does sound like premolt! I love that you described her abdomen as a grape; I used that as a descriptor quite a bit. Now, just make sure she has water and remember it can take a couple weeks or so. I have dozens of Ts, and I STILL get excited when one molts!

      Keep me updated!

      T

      Like

  5. A couple of weeks? My patience is really tested to its limits 😦

    It is a good thing that I will have my second T delivered tomorrow. It is going to be a young B. emilia. My wife is afraid that I will become like “one of these freaks on the Internet” who have 100+ spiders, so I have to plan my purchases a bit more carefully from now 🙂

    I will let you know how the molt is going to turn out.

    Like

    • Hi, Sas.

      When I started, I only had an old G. porteri, and a GBB and L. parahybana sling. Both slings went into premolt at the exact same time, and I was incredibly impatient as I waited for them to finally molt. I decided that I should probably get a couple more slings to distract me while I waited.

      80+ tarantulas later… 🙂

      Seriously, I think part of the addiction and the reason why folks get so many is that you ALWAYS have something going on, and you don’t have time to fixate when one stops eating and goes into premolt. Don’t get me wrong, I still get excited and am eager for the molt, but I’m just not fixated on it (like I was when I only had three).

      Luckily, I don’t have 100+ yet, so I’m not in “freak” territory. However, that’ll likely change over the summer! 🙂

      Like

  6. Hi Tom,

    My Brachypelma emilia has arrived. I have sent you an email to tomsbigspiders@outlook.com with some pictures. Could you help me to determine the sex (if at all possible from the pictures of course)? Thank you very much!

    Ps. I suppose every T owner who breeds with his T’s becomes easily a freak with 100+ spiders 😀

    Like

      • Hi Tom,

        Something extraordinary happened today. My albo molted! This morning she began spinning a little hammock and this afternoon she was lying in it on her back. We had a pretty good view of the whole process. She just flipped back to her feet again. It is a bit difficult to see how much she grew because she has her legs a bit close to her body. A little piece of old skin is still on her abdomen, but I don’t think this will be a problem, will it be? How long should I wait until I can feed her? A day or five?

        Now I need to read a bit more information on sexing the tarantula with the tiny little skin. I hope it will work. I will let you know if I have any success.

        Like

      • Hello, Sasker.

        That’s fantastic news! Tarantulas always seem to molt either at night or when you’re not around, so you’re incredibly fortunate to have witnessed the entire process. That’s seriously amazing.

        They are very weak and vulnerable after a molt, so she’ll probably remain in that position for a day or two. As her new exoskeleton hardens up, she’ll stretch out in odd positions and get used to her new suit. Some of the positions they assume during this period can be quite comical.

        Depending on the size of the tarantula, I usually wait 3-7 days. Slings will harden up much faster than juveniles and adults. Waiting five days should be perfect.

        The smaller the spider, the more difficult it can be to sex. That abdomen tissue is so fragile, and it’s often left torn and twisted after a molt. It takes patience; gosh knows I’ve ruined quite a few trying to spread them out. 🙂

        Again, congrats!

        Tom

        Like

  7. Hi Tom,
    I found a desert blond tarantula at work and instead of letting it die I brought it home. I live in salt lake city utah and it came on a truck and trailer from Arizona. I do believe it is a female and she was in rough shape. I think she is doing better now but she will not eat and I have had her for a week. I have a 10 gallon glass aquarium with the eco dirt that came pre made. I keep my apartment about 67 to 75 and I live on the lower floor. I’m confused on how humid I need to keep her cage for the fact that she is from the dessert which is hot and dry. She just seems to stay balled up most of the time but if I do touch her back leg she responds very well and moves. Never owned a spider before but I could not let her just sit on top of a cupboard and die until the pest guy came to dispose of her. I have been reading alot and I don’t know what to do for the fact of how I found her and how she was in the wild. Everything I read is on one’s that have been bred for pets lol. Thank you for your time

    Like

    • Hi, Vic!

      It must be the time of year, as I’ve had a lot of folks contacting me lately after finding one of these in rough shape (two were rescued from tarantula hawks!).

      It sounds to me like you’re doing a fantastic job caring for her. Personally, I wouldn’t worry about the humidity at all. They are from arid regions, so offering a water dish will do. If you’re really concerned that the air might be too dry, you can moisten down a corner of the substrate and see if she goes to it.

      Do you think that she might have been injured? It sounds like you’re giving her great care, so if she doesn’t come around, it’s likely do to something that you can’t detect.

      Could you email me a photo of her?

      Here’s a video featuring mine. She was wild caught (many in the hobby are) so the care should be the same.

      I hope that helps!

      Tom

      Like

  8. Hey, Tom! I have a few p. cambridgei slings/juvies, and I was wondering if a water bowl would be sufficient enough for their humidity rather than keeping the substrate moist as often as possible. I’ve read that they require a medium-high humidity. Their substrate is still moist but when it dries out, should I maintain the moisture or is the water bowl enough for them to survive? Thanks in advance! 🙂

    Like

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s