# Absoption of water through the cloaca/vent



## jarich (Mar 23, 2012)

I thought I would start a topic where we could discuss the topic of bathing and water uptake through the vent/cloaca. I have heard often that people say that bathing is a sure way to increase the hydration of a bearded dragon, as well as other lizards, and on the surface it seems to make sense. The cloaca is the end of the digestive tract of reptiles that, among other functions, is the site of where some of the water of the feces of the dragon, as well as the urine, is reabsorbed. So at first glance it would seem to make sense that water could then also be absorbed by soaking a dragon in standing water. The problem is that there seems to be no evidence to support this and much to support the opposite. 

Ive heard conjecturally, though Ive never seen it myself, that some have lizards who they have seen in the bath opening and closing their external cloacal vent. Just to give a bit of framework, there are two sphincters, one at the beginning or upper end of the cloaca, and one on the way out. The lower, or external sphincter, is a voluntary muscle group, while the upper sphincter is involuntary. Wastes are passed into the cloaca, where some water will be reabsorbed based on the hydration levels of the lizard. The rest will be excreted as uric acid and other wastes. This is an ingenious adaptation for conserving water, and a carefully balanced one based on colloidal osmotic action. In other words, this is a careful balance of salts and plasma proteins which draw water back into the body through osmosis so that none is wasted. It seems like trying to unnaturally usurp this process could be potentially damaging. 

What happens most often when you place a lizard in a warm bath? Yep, they pass their wastes. Im not sure that I fully understand why this is, but there seems to be two things happening. First, an increase in temperature can cause the evacuation of the bowels as the animal tries to keep temperatures constant. Second, the water can cause the relaxation of the muscles surrounding the sphincter which would then lead to the evacuate the bowels. The issue as I see it is that neither of these are naturally timed processes. Regardless of whether or not the animal is too dehydrated to go on its own, these two processes are premature in the normal digestion of the lizard. They didnt go prior to being in the bath, but rather this was something that was somewhat decided for them by the parameters of the bath. What that means is that the normal processes of absorption of water and salts from the bolus were cut short or otherwise unnaturally timed. This has the potential to unbalance the electrolytes and therefore hydration in this careful system. 

Beyond this, there is the lack of evidence to support that any water is taken into the cloaca and absorbed from a bath anyway. The absorption of water from the wastes is a slow process. In those lizards studied, absorption rates from wastes were about 7-8 ml per kg of animal PER HOUR. If you take into consideration that say a bearded dragon weighs around 1/4 of a kg, and the average bath lasts 1/4 of an hour or so, youre talking generously about 0.5 of a ml, or roughly eight to ten drops of water. However, this is for absorption by natural means within that careful system of osmotic pressure, which requires balanced salts and proteins. Now the question becomes does any water actually make it into the cloaca via a bath? 

The answer seems to be no. The only evidence I could find of any testing done was by a great guy named Dr Wade Sherbrooke. He has tested this on a few species of desert lizards, by dying water and dousing or bathing the various areas of their bodies. He was then able to determine if any water was taken in and via which ways. He found that no water was taken in through the cloaca and entered into the bloodstream, regardless of hydration levels in the lizard (Sherbrooke, 1990: Jrnl of Herp, 24:3. 302-308 ). He basically found that if water gets in, it gets in through the mouth (and sometimes in the strangest of ways). Shoemaker and Nagy (1977, Ann Rev of Phys, 39:449-471) found the same thing. 

So it seems that if your lizard drinks in the tub, and bathing does stimulate some to do so, then they would probably gain some decent hydration from it. However, it does not appear that any further hydration would be gained by other means.


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## ToothlessSav (Aug 5, 2013)

I don't bath Toothless just because I don't think it's necessary, but what you're saying makes a lot of sense. I would think sub-qs or oral fluid would be of more benefit for dehydration. From what I've read, some reptiles can absorb a small amount through their scales, but that amount would be minimal.
Better ways to re-hydrate than soaking in my opinion .


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## Debbie1962 (Dec 5, 2008)

I was told by an exotics specialist that they can hydrate through water entering the cloaca but that was years ago and maybe evidence now suggests differently. I would guess that water may get through some of the skin to help. As the above poster I do not bathe healthy animals anyway, they be hydrated enough through their diet. Sick animals may be bathed and drink which will help.


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## Salazare Slytherin (Oct 21, 2009)

Fab post jarich , using my phone ATM so can't reply it will take forever , I will come back and share some of my thoughts and expirienced when I get back to the main computer, overall I do agree with the majority of what your saying though and I seriously needs to be myth busted.


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## Salazare Slytherin (Oct 21, 2009)

Debbie1962 said:


> I was told by an exotics specialist that they can hydrate through water entering the cloaca but that was years ago and maybe evidence now suggests differently. I would guess that water may get through some of the skin to help. As the above poster I do not bathe healthy animals anyway, they be hydrated enough through their diet. Sick animals may be bathed and drink which will help.


They don't drink through their skin either  reptile skin is highly prized for the leather trade, what possible purpose would a leather handbag have that obsorbed water  the skin itself is compiled together of a tough and strong keratin based protein (completely 100% waterproof.


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## Debbie1962 (Dec 5, 2008)

> They don't drink through their skin either  reptile skin is highly prized for the leather trade, what possible purpose would a leather handbag have that obsorbed water


True. But being a lady that doesn't believe in such bags etc. that thought did not occur to me.


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## Salazare Slytherin (Oct 21, 2009)

Debbie1962 said:


> True. But being a lady that doesn't believe in such bags etc. that thought did not occur to me.


It doesn't to most people I have met and spoken too either, ironically some with leather handbags  being an animal care forum other trades and cultures way are often dismissed, largely ignored or just not acknowledged, as cruel as many of these trades are, they can still teach us a lot


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## Shrimps (Mar 20, 2014)

Good read Jarich, it's really interesting to see the response this gets in different communities. The range of "there's no proof so maybe it's not true" to "there's no proof so it must be true" is curious. :whistling2:

I can see how baths would stimulate drinking, but I've never seen my lizards drink in the bath. My guess is they weren't/aren't dehydrated enough to trigger the response, but finally I would rather drip water on my dragons face that he will lick off to his own satisfaction than shove him into a tub he doesn't want to be in and hope it goes in the backdoor. 

Regardless of if it works or not (to take the approach of data is inconclusive) it always seemed like a strange notion to not provide water, abhor humidity and somehow be confident a few baths per week is going to keep the animal healthy. =\ but there seems to be a lot of kidney/gout problems too... 

As an actual question though, don't some reptiles have this ability? I want to say it was chelonians I read about? Or in general is the clinical advice to give baths (for minor dehydration) perhaps misconstrued from an original intent of encouraging active drinking?


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## jarich (Mar 23, 2012)

There are some turtles that seem to yes, as well as being able to breathe through their cloaca! Makes much more sense though for a water based animal. There are also birds who cool themselves by opening their vents and allowing for evaporation. I wonder if that might be why sometimes people say they see their lizards opening their vents in the tub. I'm sure it must mess with their thermoregulation quite a bit when people take their lizard from say the cool side of an enclosure (say 80 F), and dump them in a 95 F tub of water. 

As for that other community, ya it's sad really because any new information seems so threatening for some reason


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## Whosthedaddy (Nov 29, 2009)

Interesting read, I side on the 'no' side of the argument.


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## Shrimps (Mar 20, 2014)

I had another thought in this, and figure it's a safer place to pose the question. I know with snakes we are taught to do nothing to the animal at all for 1-2 weeks, and only bother it to spot clean and change water and maybe feed. It seems like baths for certain lizards are almost treated like mandated care on the scale of cleaning up poop, in certain circles anyway. Wouldn't baths, especially if the baby isn't used to it (say from a pet-store like most dragons are) be adding to the stress of the new situation?


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## jarich (Mar 23, 2012)

Sorry Shrimps, I missed your last question there somehow. I think its a trade off. Its fairly common that dragons will drink in the bath, especially if you mist their face, so a dehydrated dragon could get some benefit from being bathed. However, its not normally necessary as they get the water they need from their food. So I guess its really up to the keeper and whether they think its necessary in the trade off of some added stress or not. 

I would like to give a bit of an update too. I contacted a few authors of the studies Ive read lately regarding this subject (Dr Wade Sherbrooke, Dr Glenn Tattersall, Dr Doug Mader, Dr Paul M Gibbons). The last two are very well known vets (Im sure many of you will recognize the names) who teach other vets and write textbooks and other vet manuals for reptile treatments. They universally agreed that lizards do not exhibit any cloacal drinking, as they called it, and that this was considered common knowledge in the scientific field. One of them actually seemed to find it quaint that I was bothering to ask still. I felt a little foolish for not being more up on current research in the end. :blush:


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## Kerrabutt (Jan 20, 2013)

Can't believe this was actually a thing. It'd be like running a bath and sticking your arse in it to rehydrate after a night out.


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## lewkini (May 12, 2009)

As a fairly new beardie keeper i listen a lot to advice I'm given albeit very mixed advice.

I was bathing once a week as this was what i was told/advised on here and the dreaded BDUK on Facebook but i was so concerned about him becoming dehydrated i upped it to every other day. Altho that said he very very rarely drinks whilst in there. If I'm honest it did seem to make him appear brighter but maybe thats just coincidence!

I still find it hard to understand how a beardie can get most its fluids from its food hence why i bath.

I also don't supply water in the viv as i was told it may not be needed which i like the idea as the way he trashes his viv it would just mean water everywhere!

Im all open to suggestions and more advice on whats best but anyway i can avoid water in the viv id like cause of my reasons above

Lewi


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## Rob_H (Apr 19, 2010)

Interesting post. Has anyone tried weighing their lizard with some accurate scales before and after sticking it in the bath? If you make sure they're properly dried off afterwards, and take note of whether they drink or defecate, then any weight gain shows that water is being taken up somewhere.

There is a big difference in mass between a dehydrated and hydrated lizard, so this should be detectable.


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## jarich (Mar 23, 2012)

Nothing wrong with bathing your dragon Lewi, as it does present them with the option to drink, should they want to. Id also recommend providing them with a water dish for that reason, just in case. However, these wonderfully adapted lizards get the moisture they need from the food they eat.

I believe there are studies like that Rob, but so far Ive only found them on turtles and amphibians. Dr Gibbons made reference to them with lizards, but I havent found them yet. I have seen numerous studies on the permeability (or rather lack thereof) of the skin to water however.


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