Third Edition (2009)



LAST UPDATED ON 2013-July-03


A rudimentary ICU was first used by the authors while they owned Noah's Ark Pet Shop, Inc. in E. Lansing, Michigan between the late 1960s and mid 1970s. At that point nothing was known of tarantula medicine, and indeed little was known outside academic circles about tarantula physiology. The authors, in a last ditch effort to save a tarantula in great stress, resorted to placing it in an aquarium with a layer of wet aquarium gravel for several days. Lo and behold! It got better! This technique was tried on several other tarantulas over a period of time and seemed to work wonders. It has now been accepted as a basic component of tarantula medicine.

The concept of using something like an ICU to treat medical problems with tarantulas was first published in the second edition of the Tarantula Keeper's Guide (aka TKG2 ) in 1998. As the book was being written a term was needed to describe the construct and the process, and since both co-authors were working in a research lab in a medical school (University of Calgary, Faculty of Medicine) at the time, it just seemed natural to call it an Intensive Care Unit after the clinical ward used in hospitals to treat human patients in great, medical stress.

It has since proven itself to be a valid and usually successful treatment for any circumstance in which a tarantula may be too weak to maintain normal body posture or limb function. In fact, these author's "first responder" action for any tarantula malady is the ICU. After it's placed in an ICU other modes of treatment are then considered secondarily.

Since that time the treatment has been streamlined and simplified to the one presented here. But, enthusiasts (apparently unable to understand that simple is often much better) still seem hellbent on making it as complicated and elaborate as possible, perhaps due to their disbelief that anything so simple could be so effective. Be forewarned that these more elaborate and complex systems do not work any better than the simple ICU presented here. Simple is better. Cheaper, too!


Acquire any sort of waterproof, plastic container large enough to hold the tarantula comfortably. In our example we are using a dessert topping tub, but others have used plastic cottage cheese cartons, candy tubs, even a plastic corsage box with good results. Use whatever is handy. You're not using it because it's beautiful. You're using it because it'll do the job, because a valued tarantula is sick and dying, and because you don't have a lot of time to waste.

Wash the container well, and rinse it well.

Make two or three small ventilation holes in the side walls. Here, we heated a large nail on a burner on our kitchen range, but merely carefully piercing the walls with a sharp implement might also work as well. Just be careful to handle a hot nail with pliers, or be very careful not to stab yourself in the hand with a knife or pick.

Why two, or why three? Use two holes for smaller ICUs and three for the larger ones. The exact number is open to a lot of interpretation on your part. We used three holes in our container because it was fairly large, almost six inches (fifteen centimeters) wide. Two would probably also have worked as well. One hole might also have worked. Don't obsess over the small stuff.

These ventilation holes should be between 1/8 inch and 1/4 inch (3 to 6 mm) in diameter. Why? Because holes much smaller than that may not allow enough ventilation to suppress mold growth, and much larger than that will allow too much ventilation, reducing the relative humidity within the container below useful levels. Note that the consideration of the tarantula suffocating from lack of ventilation does not enter into the equation. Tarantulas have such slow metabolic rates that it is very difficult for them to suffocate. In all the years that these authors have been keeping tarantulas and helping others with them, they have NEVER heard of a situation where a tarantula died of suffocation.

The ventilation holes should be placed high enough up the side walls to prevent water from dripping out, but low enough that the cover won't obstruct them when it is installed. If your container is made so that you cannot put holes in the side (e.g., a glass bowl or jar), place the ventilation holes in the lid and use it anyway for now. You can always find a better container later. We try to avoid putting holes in the lid because if something is subsequently placed on top of it, the ventilation holes could be completely blocked. In truth, we're not entirely sure that would have any bad effects, but why take the chance with an already sick tarantula?

Note that we dwell on the character and placement of these holes only because there undoubtedly will be those enthusiasts who insist on being given hard and fast guidelines. For the most part, read the recommendations above and try to comply, but do not waste a lot of time or effort, or become too obsessive about getting it "just right." Close enough is good enough. Simple is better. Getting it done ASAP is much more important. After all, it IS called an ICU and used for emergency medical treatment!

If you try to use plastic food wrap, aluminum foil, or some other light, fragile covering material on the ICU, the tarantula could chew its way out once it regains its strength. As unlikely as it sounds, this has happened! Use only the original, tight fitting cover, or find a better container.

Fold a sheet of paper toweling so that it will fit comfortably in the bottom of the ICU. Here we merely folded it in quarters. If your container is smaller you may need to either fold it in thirds each way or cut the sheet of toweling to a slightly smaller size. Again, do not obsess about this. Just about anything close will work just fine.

Stuff or place the folded paper towel into the bottom of the container to make something that resembles a small nest. It should be large enough to hold the tarantula without cramping it. If the container is too small for this, use it now anyway. You can find a better container later. Generally, a little too large is better than a little too small because as the tarantula recovers it will begin moving around and we presume it'll be more comfortable in the extra room.

Pour in an excess of room temperature water. It doesn't have to be distilled water, spring water, bottled water, rain water, boiled water, or anything else exotic. Tap water is just fine, even if it smells a little like chlorine or sulfur. However, it would be best if you could avoid using softened water because of its excessive salt load. Again, do not obsess about this. Just about anything close will work just fine for now. You can fine tune it later.

Now, pour all the excess water out until the ICU is merely dripping wet. The paper toweling should remain sopping wet. Can you see the glistening water on the paper towel in the photo above?


Place the ailing tarantula directly on the wet paper toweling. It MUST get its feet and "belly" wet.

Install the cover. Make certain that it's secure. You don't want the tarantula to get loose once it regains its vigor.

Place the ICU with its tarantula in a warm part of the house. In these authors' home the default position was on top of the refrigerator because of the gentle, low heat from the heat exchanger coils on the back. But, your home may be different. Protect it from sunlight and excessive heat.

Now, prepare a second, empty ICU for use later. The two do not necessarily have to be identical. We're much more interested in function than beauty here.

Check on the tarantula every day. This will be particularly easy if you were lucky or wise enough to use a transparent deli cup. Otherwise, you'll have to remove the lid for the inspection. Don't waste time looking for a transparent container while your tarantula dies! Use what you have available now. You can always upgrade to something better after the tarantula is ensconced in the not-so-desirable ICU.

You can leave a tarantula in an ICU for one or two days, maybe even a third day at a time. But after that the bacterial growth on the paper towel (especially if the tarantula vomited or defecated) and even on the tarantula itself can become dangerous. We strongly urge that you thoroughly clean or set up a new ICU every second or third day. Preparing that second ICU in advance (see above) comes in real handy at this point.

After about six days in an ICU it's probably a good idea to remove the tarantula to its cage and allow it to dry out for the afternoon, if not a full day. This will help to control bacterial and fungal infections on its body. You can always return it to a cleaned ICU later if necessary.

Depending on what was originally wrong with the tarantula you may want to completely clean and redo the original cage while the tarantula's in the ICU. It makes no sense to try to cure your pet tarantula, then return it to the same cage in which it got sick in the first place!

When do you permanently remove it from the ICU? When it's obviously alert again, and moves around with little difficulty. Or sadly, when it begins to smell dead. BUT, DO NOT THROW YOUR TARANTULA AWAY AS DEAD UNTIL IT ACTUALLY SMELLS DEAD.

Be aware that tarantulas are very good at playing 'possum, and a tarantula that appears near death as you place it in the ICU can experience an amazing resurrection in just a few hours or days. Whenever you open the lid for an inspection always expect it to try to make an escape as soon as the cover is removed. For the "pet rock" varieties this is unlikely, but there are species known to be real speed demons that you need to be prepared for.

BE FOREWARNED! You may be happily surprised at its recovery, but devastated as it leaps to its death on the floor!


To be honest, we don't know how an ICU works. We do know, however, that they do work. If we were pressed to spin a believable story ...

  • Butt, A. G. and H. H. Taylor. 1991. The function of spider coxal organs: Effects of feeding and salt-loading on Porrhothele antipodiana (Mygalomorpha: Dipluridae). J. Exp. Biol. 158:439-461.

  • Cloudsley-Thompson, J. L. 1967. The water-relations of scorpions and tarantulas from the Sonoran Desert. Entomologist's Monthly Magazine. 103:216-220.


It is likely that the reason a tarantula appears weak or half dead is the result of it not being able to muster enough hydraulic force to move its legs or support itself. One reason for this might be extreme dehydration. It may be completely conscious and otherwise in good health, but paralyzed from dehydration. Clearly, in this case the first treatment should be to get water into the tarantula to resuscitate its hydraulic system.

It is highly unlikely that a tarantula could absorb water directly through most of its exoskeleton. Most of the exoskeleton is covered with a layer of a wax-like substance that prevents water leaving the tarantula. (In fact, their exoskeleton may be better at retaining water than our skin because they don't possess sweat glands!) It would then seem rational to assume that if water can't get out, it also can't get in. However, there are several places on the tarantula's body where the exoskeleton is very thin and might be able to absorb water, namely the pleural membranes at the leg joints and between the body plates. (Some have also suggested the book lungs, but that would risk drowning and is highly unlikely.) As far as we are aware, no one has definitely ruled out the possibility of water absorption at those points. (But see Cloudsley-Thompson, 1967.)

So it would seem possible that water is absorbed through the pleural membranes in sufficient quantities to affect a cure, providing those membranes were wetted by the water in the ICU. Is this what happens? We're not sure.

There is yet another potential entrance point for water that seems to have been completely overlooked by the enthusiast, perhaps because it's too obvious: The mouth!

It seems that to sip water or digested food, the tarantula must use its sucking or pumping stomach, and the function of this organ does not rely on hydraulics, as leg movement does. Except in the most extreme stages of dehydration where muscle function itself is compromised, the pumping stomach muscles still work just fine. So, the hypothesis is that to revive a dehydrated tarantula all we need do is get water to the mouth. This contention is supported by several instances where enthusiasts have reported saving their tarantulas by holding them upside down in their hands and dripped water on their oral area. The problem is that not everybody is willing to become that familiar with a tarantula, and not all tarantulas are entirely safe to handle in this way.

However, if a tarantula is placed "belly" down on a wet paper towel it may be able to drink the water if it can get its mouth wet.

But, there is yet another way to get water to the tarantula's mouth! In 1991, Butt & Taylor determined that a close relative of tarantulas uses fluids secreted by the coxal glands on its sternum (chest plate) to aid external digestion. The fluid seeps forward by means of the crevices between the plates on the tarantula's "chest" and moistens the food bolus during feeding. It is entirely possible, though yet unproven, that a tarantula in great stress from dehydration might also be able to sip water that finds its way into those crevices and seeps forward to the mouth. It's a good story anyway!

This is why we urge that you arrange for the tarantula to rest with its "belly" on the moist paper toweling. It isn't going to do any harm, and it just may save your tarantula's life.


A second, entirely conceivable scenario, involves a tarantula that is so sick that it is unable to muster the energy required to produce the hydraulic force necessary for functional movement whether it is adequately hydrated or not. Putting such a tarantula in an ICU may very likely have little or no effect whatsoever, and the tarantula will die anyway. We regret that life is often simply not fair.

However, since it is nearly impossible for the enthusiast to distinguish the two cases (i.e., extreme dehydration and extreme muscle weakness), and indeed they may occur simultaneously in the same tarantula, and because using an ICU is such a benign treatment, we strongly urge that ANY sick tarantula be first moved to an ICU before other potential treatment modalities are considered.


As a preemptive strike, you might consider making two ICUs in advance and keeping them in your Tarantula Emergency Kit . You are establishing such a Kit, no?


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This page was initially created on 2010-January-09.
The last revision occurred on 2013-July-03.