Is my cage too big for a pair?

[Pim]

Hi I currently have a line male in a 40 gallon. I was hoping to soon introduce him to a friend. Should I get two because my tank is bigger? Will that risk a declan? If I only have a pair will it risk a declan?

Thanks 🙂 I also have a pair in a 29 gallon could you answer the questions above if that is too big for them. They will probably not be able to have a partner though because it’s too risky.

[pigsfuns35]

Mar 20, 2019 6:12:40 GMT -8 Pim said:

Hi I currently have a line male in a 40 gallon. I was hoping to soon introduce him to a friend. Should I get two because my tank is bigger? Will that risk a declan? If I only have a pair will it risk a declan?

Thanks 🙂 I also have a pair in a 29 gallon could you answer the questions above if that is too big for them. They will probably not be able to have a partner though because it’s too risky.

Hello! Based off of what I heard a forty gallon is way to big for a pair and could cause declanning issues. Usually that cap is 20 gallons to prevent declan.

[tuftsnfluff]

Hey there!

Where there have been many successes of aquarium tanks all the way up to 60 gallon for a pair of gerbils..  the larger you go past 20 or 29 gallons, the higher the chance of declanning.

Cage toppers can do this too, I suspect because there's a floor to them.

Usually the reason is you are allowing sufficient space for them to be pretty far away from each other and practically giving each gerbil their own area to claim as territory. 

Once they do that, then things get iffy.  

Because gerbils are a social society and they want to mix and mingle, but there wouldn't be any "neutral ground"  as there would be out in the wild, so one crosses into the others "territory" in order to be social and the other wants to defend.   This leads to squabbles, then side arching, boxing matches, till a full out fur flying ball up.

For burrowing creatures, remember, my saying is " Snug is Safer"  and recommendation is least 5 to 10 gallons per gerbil.

I usually recommend highest for a pair being 29 gallons.  That's about 14 gallons per.  Plenty for the spunky critters.

Most of the time I see or hear that enclosures that are 40 gallon all the way to 60 or 70, sound like its because people want to make these elaborate set ups for their gerbils and give them all this stuff to have and interact with.  

Where this is great and I'm thrilled their owners want to be so attentive and involved, they wouldn't have access to all that in the wild in the desert.

So, in a way you have to think.. is this for US or for THEM?  We certainly don't want it to be like spoiling our children.

Also, in regards to the pair in the 29 gallon, that's the highest I would recommend. 

I notice you stated "" they will probably not be able to have a partner..."    

It is not recommended to intro another gerbil to an already established pair.  

In fact, again, like the tank size situation, where you hear successes of three and even four-some's working out, the more you add beyond a pair, the higher the risk of an issue down the line to a Declan.

I myself have had a Foursome of brothers work out till passing away of old age in a 20 gallon long.    Its the only one I have had past a pair in 15+ years of gerbil ownership.

I have never heard of a foursome of females working out.  Only twice have I heard of a female threesome making it together.

So best not to risk the situation, especially if you do not have the room to manage or care for a multiple tank set up past two tanks.

Hope this helps!

[nazasaki]

I was one of the unlucky souls to have a pair have a nasty territorial fight in the 40 gallon. It was a big beautiful setup with lots of room....came home from work and my boys were an awful bloody mess. I took advice from the forum and ended up placing them in a 15 gallon and they have been housed successfully together ever since. I must say I dont at all miss the 40. It was big, cost me a small fortune in bedding and we also had a hard time finding enough space in our livingroom to place it in as to not take away from our own living space. I had previously kept gerbil pairs in 10 gallons tanks and never once had an issue. I think it's great how people want to give their gerbils more space but at the same time things like declans happen which makes me think that they are not all that happy regardless. Use your own judgement! If that large tank works for your pair than that's fine, if you want to get a smaller tank like a 20 gallon than that's fine too I would think the 29 you have mentioned would be a nice sized setup.

[Lysandra]

So I had a pair of male gerbils in a bin cage that was 99 litres which I think is about 30ish gallons, granted there weren't any shelves in the cage per se so it was just the floor space. I never did have any inherent issues with that, they lived in it for almost a year until the one passed from health issues, but the thing is, these 2 were from a previous batch the pet store had had so they were on their own for probably almost a month in a smaller cage so then they would have bonded as a pair and gotten used to each other. I also have a trio in that same cage now and never had any issues with declanning, but they've only been in there for a few months. Unfortunately they found a way to grab onto on of the smooth edges to begin chewing and are on their way to escaping, so I'll be transferring them to a 20 gallon high with various ledges. I think it can kind of depend on how used to each other the gerbils are when you put them in such a large cage because I never had any issues, and they always made their den together and slept with each other. Actually for my first pair when the one male passed, the other refused to leave him and we almost lost him as a result of too, they obviously got along very well. With the pair in the 29 gallon I don't think I'd honestly be that worried because in doing conversions, it seems that the 99 litres converts to about 27 gallons and I never personally had an issue, especially with them being in there already...

[shab]

Mar 20, 2019 8:14:02 GMT -8 tuftsnfluff said:

Hey there!

Where there have been many successes of aquarium tanks all the way up to 60 gallon for a pair of gerbils..  the larger you go past 20 or 29 gallons, the higher the chance of declanning.

Cage toppers can do this too, I suspect because there's a floor to them.

Usually the reason is you are allowing sufficient space for them to be pretty far away from each other and practically giving each gerbil their own area to claim as territory. 

Once they do that, then things get iffy.  

Because gerbils are a social society and they want to mix and mingle, but there wouldn't be any "neutral ground"  as there would be out in the wild, so one crosses into the others "territory" in order to be social and the other wants to defend.   This leads to squabbles, then side arching, boxing matches, till a full out fur flying ball up.

For burrowing creatures, remember, my saying is " Snug is Safer"  and recommendation is least 5 to 10 gallons per gerbil.

I usually recommend highest for a pair being 29 gallons.  That's about 14 gallons per.  Plenty for the spunky critters.

Most of the time I see or hear that enclosures that are 40 gallon all the way to 60 or 70, sound like its because people want to make these elaborate set ups for their gerbils and give them all this stuff to have and interact with.  

Where this is great and I'm thrilled their owners want to be so attentive and involved, they wouldn't have access to all that in the wild in the desert.

So, in a way you have to think.. is this for US or for THEM?  We certainly don't want it to be like spoiling our children.

Also, in regards to the pair in the 29 gallon, that's the highest I would recommend. 

I notice you stated "" they will probably not be able to have a partner..."    

It is not recommended to intro another gerbil to an already established pair.  

In fact, again, like the tank size situation, where you hear successes of three and even four-some's working out, the more you add beyond a pair, the higher the risk of an issue down the line to a Declan.

I myself have had a Foursome of brothers work out till passing away of old age in a 20 gallon long.    Its the only one I have had past a pair in 15+ years of gerbil ownership.

I have never heard of a foursome of females working out.  Only twice have I heard of a female threesome making it together.

So best not to risk the situation, especially if you do not have the room to manage or care for a multiple tank set up past two tanks.

Hope this helps!

I'm curious where this information about not going over 29 gallons comes from, do you perhaps have something I could read through?

[tuftsnfluff]

It's mostly from 10-15+ years of gerbil husbandry experience, several various research papers from renown laboratory and University sources on how gerbils behave in the wild, experimentation, and hearing about the many, many multiple failures with such over several years.

In the early 2000 years, my first gerbils ever came from Houston, a gang of Four brothers I called the Yoningumi Boyz.  

At the same time, I found a pair of boys at a local pet store. 

I admit I wanted to do what everyone else wants to -- get a good sized tank so the gerbils can have lots of room to run and play with toys and sand to roll in and sticks and substrate.

So, I got a 45 gallon tank and placed the pair in it.   I took my gang of four and placed them in a 20 gallon long.

WHY I did this, I can't tell you.  Made more sense to put the foursome in the larger tank.  But for some reason, I didn't.

The tanks were on opposite sides of the room.  Things were great for a while, till the pair turned about 8 months old.

Nothing changed, I did everything I always did, including always washing my hands with the same soap when going from cage to cage.

They ended up getting into a nasty fight and de-clanned.

Separating each one into a 10 gallon, I wondered what to do.  I found a breeder about 30-45 mins from my location at the time.

I got two same sex pairs.   So now, this beginner in gerbils went from two tanks to now to SIX tanks -- One 45, One 20, and Four 10 gallons. 

Cleaned the 45 gallon vigorously, paying attention to each nook and cranny.. and started all over again.

Things were good for a while, then I started noticing that the gerbils in the 45 "acted a little wiggy" when they ran around the tank.

One with one side would tense and get a little stiff when the other came over, and same with the other side of the tank with the other gerbil

At times, they would pause what they were doing and box a bit in the middle of the tank.   I really didn't think much of it.

A week later, I came home to a bloody mess and one of the gerbils was killed.

Frustrated at this time, I took the empty 10 gallon and split tanked the remaining gerbil with one of the original pair that was in the tank before him.

I started researching, talking to the breeder, and heard about and joined the AGS and upon various things I was hearing I decided, okay, I'm experimenting with this.

Already at two failures, I got another pair and tried again.     Another failure.     It literally took six pairs before FINALLY one pair, a rather easy-going, gentle pair of males, succeeded in the 45 gallon till passing away of natural causes.  By this time, I had about 12 tanks.  Most of them 10 gallons.

What about the Gang of Four, you say?

Never, ever had an issue with them.  They stayed happily together till them passing away at different times.  One lived for 5 years and his brother and first sire of my Kennel at that time, lived to be six.  I've NEVER been able to keep gerbils in more than pairs ever since without de-clanning, especially these days. 

These days, gerbils in captivity, if anything, seem WAY more touchy and need more careful attention to handling  and care than they did back then. 

I finally got rid of that 45 gallon tank, gave it to my sister who wanted an aquarium.

Through the years, I've heard more de-clanning stories regarding gerbils in large tanks over 29 gallons than I have success stories.

All in all, I know what WE would like or want to do with our beloved pet gerbils.
But we have to remember, it isn't UP to US.
It is based on them -- their personality, their instincts, and the structure of their society.
I know they are wonderful, curious, fun loving little fur-balls we’d love to have more of, but we also need to be responsible in following the rules of their society and in just how many proper sized tanks we can keep and ethically care for.

Majority of the time, we just cannot make them do what is not in their nature to do.
They are social, yes,  but their “burrow-type” social society in the wild is not like a whole family clan piled up on top of each other in one big, huge burrow.
It is a structured tunnel system with smaller burrows separated out a good distance from one another and either a large burrow for neutral ground or above ground being neutral ground.

Where trios and foursomes can work in tanks over 29-30 gallons- it gives them too much space, which can allow each gerbil to risk wanting to "claim" a territory, and this causes issues with them wanting to interact with each other.  Gerbils do NOT need a lot of space to make a territory.  10 to 15 gallons of space is all they really need, even in the wild.  And we also have to consider that in the wild, when gerbils cross into territory of another gerbil, they can run away, which isn't possible within a contained pet environment.  

Since then, I have kept gerbils in pairs and in nothing larger than 10 to 20 gallon tanks.  Sure, there's been the odd De-clan here and there. 

But usually its because of a mistake I or my husband made or personalities just did NOT mesh, even with siblings.

It happens.

But overall, my Kennel of 25 tanks and about 36 gerbils (I've some loners and a few singles I'm trying to buddy up) rarely ever has a Declan.

I'm not saying that there aren't success stories with pairs, trios, or foursomes in huge tanks.   It DOES happen.  

I say that's real lucky with getting some gerbils that are very laid back.

And I'm not saying its impossible to keep gerbils in more than pairs in smaller tanks - again, it DOES happen.

But this is not the "Norm" for their society.

So -- because of everything I have learned, heard, and had experience with, I will never recommend to anyone to keep gerbils in more than PAIRS and in NO larger a Tank than 30 gallon.

Sorry for the novel but really wanted to thoroughly answer your question. 

Hope this helps!

[shab]

thanks for the answer, do you by chance have a link to the research?

[tuftsnfluff]

As to links, any I saved back then was at least a decade and three computers ago.

I don't save now, but I do continue to take a few hours a week to continue to do research on my favorite four-legged fuzzy. Any pertinent information I find I share here when I find it.

There are vast reliable sources of information in regards to gerbil behavior not only in the wild but also in captivity, you just have to take the time and diligently research it.

There's also a lot of misinformation out there too and information sites, like Wikipedia per say, that allow users/readers to change information or add to.

So, be careful in what you select to read and check their sources. 

Animals cannot speak to us where we can least understand so, anything reliable will be based on observation and hands on experience.

Nothing will be 100% or can it be said that this is exactly how a species will behave all the time, every time.

Everything changes and behaviors evolve.  Even us!

 

I CAN say for certain, how gerbil behavior was 12 years ago has certainly changed through the years --such as male and female temperaments, longer time in split tanking, blood being drawn meaning irreconcilable pairing, and etc.

[shab]

Jul 2, 2019 5:17:36 GMT -8 tuftsnfluff said:

As to links, any I saved back then was at least a decade and three computers ago.

I don't save now, but I do continue to take a few hours a week to continue to do research on my favorite four-legged fuzzy. Any pertinent information I find I share here when I find it.

There are vast reliable sources of information in regards to gerbil behavior not only in the wild but also in captivity, you just have to take the time and diligently research it.

There's also a lot of misinformation out there too and information sites, like Wikipedia per say, that allow users/readers to change information or add to.

So, be careful in what you select to read and check their sources. 

Animals cannot speak to us where we can least understand so, anything reliable will be based on observation and hands on experience.

Nothing will be 100% or can it be said that this is exactly how a species will behave all the time, every time.

Everything changes and behaviors evolve.  Even us!

 

I CAN say for certain, how gerbil behavior was 12 years ago has certainly changed through the years --such as male and female temperaments, longer time in split tanking, blood being drawn meaning irreconcilable pairing, and etc.

What do you think of the information based on veterinary/zoologist recommendations that suggest much larger habitats (55+ gallons)? Most of this information is currently only available in German, but the gist is traveling in English as well.

[tuftsnfluff]

Aug 5, 2019 11:26:33 GMT -8 shab said:

Jul 2, 2019 5:17:36 GMT -8 tuftsnfluff said:

As to links, any I saved back then was at least a decade and three computers ago.

I don't save now, but I do continue to take a few hours a week to continue to do research on my favorite four-legged fuzzy. Any pertinent information I find I share here when I find it.

There are vast reliable sources of information in regards to gerbil behavior not only in the wild but also in captivity, you just have to take the time and diligently research it.

There's also a lot of misinformation out there too and information sites, like Wikipedia per say, that allow users/readers to change information or add to.

So, be careful in what you select to read and check their sources. 

Animals cannot speak to us where we can least understand so, anything reliable will be based on observation and hands on experience.

Nothing will be 100% or can it be said that this is exactly how a species will behave all the time, every time.

Everything changes and behaviors evolve.  Even us!

 

I CAN say for certain, how gerbil behavior was 12 years ago has certainly changed through the years --such as male and female temperaments, longer time in split tanking, blood being drawn meaning irreconcilable pairing, and etc.

What do you think of the information based on veterinary/zoologist recommendations that suggest much larger habitats (55+ gallons)? Most of this information is currently only available in German, but the gist is traveling in English as well.

In regards to this information, I suppose I would have a few questions to ask about that.  One would be -- is this a "habitat" or "enclosure" meant for more than one gerbil, like perhaps a zoo or research center would have?  In this way, there would be plenty of ideal acreage in order to create and perhaps maintain a society of gerbils with adequate distance and burrowing space that could mimic what they would do in the wild.   If so, this is usually WAY more than the average animal lover can create and care for and I would never recommend this kind of thing in someone's backyard.  

  

Where I'm not sure about a zoologist, but regarding vets, and not to put down any veterinarians by ANY means, my experience of them is honestly, they don't know a great deal about gerbils.  Even some specialized small animal vet's I've gone to over the years.  Which is surprising considering how long gerbils have actually been around, people STILL look at them and have no idea what they are.

I had one Small Animal Vet pretty much straight up tell me just a few months ago to that question, "When "small animal" is mentioned -- people mostly have "hamsters, mice, guinea pigs, and rats".  Anything else in the rodentia family is just not that common.  Therefore, training and education is spent on learning in depth about the animals most popular to make better use of expensive education and better treat what is seen more often."   Then she took my card and information and told me she was going to call me when she needed to know something about gerbils!  LOL   I'm sure she was joking.  But she did say she got calls about where to get gerbils and she was confident in referring to me.  That was sweet of her.

Regardless, as far as enclosed, tank type habitats, I stand behind my recommendation for no larger than 30 gallons for a PAIR of gerbils. 

There's just been too much information written on it in regard to the issues it causes, but the BEST information ever for it is the hands on, witnessed experiences over and over by not only myself but several gerbil breeders and gerbil enthusiasts I have known.  Even by members here on this forum.  Its really not hard to find the de-clanning issues about this

  

Perhaps this could change down the line.   It's certainly possible.   Gerbil behaviors have changed, I feel, dramatically from the early 2000s to now. 

Despite what anyone SAYS, I feel the best thing to do is always go by what it seen and witnessed by the animals themselves.

If you watch and observe, they will show you more about themselves than anyone can really advise.

[Markpd]

I was reticent about bumping this oldish thread, but it's still relatively recent, and often turns up in Google (etc) searches by new members. If you don't want to read my replies and questions to tuftnsfluff I have created a new thread discussing cage size vs declanning, along with a load of links to research papers (some of that info is based on my replies below JFYI). [thread link gerbilforum.proboards.com/thread/35073/cage-size-declanning-causes?page=1&scrollTo=303431 ].

I'm hoping that tuftsnfluff will reply to this, but seeing as she hasn't logged in since March last year, it doesn't look very likely, nonetheless I think it was worth posting my message.

Tuftsnfluff
Before I start this discussion I would like to say that I'm not dismissing your many years as a breeder, nor denying that you have a wealth of experience that you have gained of Gerbil behaviour and keeping.
I have limited real experience, but what I have been doing a lot of during lockdowns (and some afterwards) is reading as much as I can about de-clanning and whether their is any connection to large cages.

This idea that large tanks can cause de-clanning I find baffling (and is what set me off onto my investigation), primarily because on the face of it, it doesn't make sense because in the wild they (effectively) have infinite space, and far more space than any cage we could (likely) realistically provide (I'm talking about an individual group here, not the space amongst many groups).

I have no experience of de-clanning myself (the current pair I have I only got on August 2nd, prior to that it was 32yrs ago! lol), but when I 1st came across this 'max size' rule I decided to start reading up on it (still not done). Looking at the research papers I can read which aren't behind a paywall, animal charity/rescue centre sites, breeders sites, notes/observations from experienced Gerbil breeders and owners here and elsewhere, it seems to me (so far) that overall their is no real evidence of the max size rule, e.g I haven't yet come across any research papers stating it (although their are a few I have yet to read, like the aforementioned pay walled ones). I have found a few indirectly contesting it though.
I've so far only found a few sources supporting the max size cage rule, including yourself, this forums FAQ 'Which Tank Size' thread (which states the info was adapted from another thread of unknown source and which the link is now dead), so we've no idea of the original source there,  smallfurryfriend.com (with an unknown source from a forum, he doesn't recall which) and gerbilwelfare.com which unusually for them doesn't have any referenced research. I would be interested in reading more if you know of any?

....the larger you go past 20 or 29 gallons, the higher the chance of declanning....
Usually the reason is you are allowing sufficient space for them to be pretty far away from each other and practically giving each gerbil their own area to claim as territory

I'm sorry but I can't see how that could possibly be the case there, compared to the wild even an 80 gallon tank is small and not that much space, Gerbils in the wild have been documented to make burrows several metres across and over a metre deep with multiple burrows (for 1 clan), see p218/219 books.google.co.uk/books?id=qyfvCQAAQBAJ&lpg=PP1&pg=PP3#v=onepage&q&f=false.
If large spaces alone caused declanning their wouldn't be any clans in the wild.
I can see though that if their are separate sections within a large cage which can be easily blocked/fended off by a Gerbil to stop another Gerbil getting there, that could cause declanning issues.

Most of the time I see or hear that enclosures that are 40 gallon all the way to 60 or 70, sounds like it's because people want to make these elaborate set ups for their gerbils and give them all this stuff to have and interact with.
Where this is great and I'm thrilled their owners want to be so attentive and involved, they wouldn't have access to all that in the wild in the desert.

I'm assuming you're talking about surface items here? But they would have access to various items though in the wild as they forage, it would be much more spread out of course!, and they would have far more space.

Although apparently they generally don't venture 'far' from their burrows due to predators (understandably! ), it can still be in the region of several metres, but sometimes much further!

I found a video of their natural environment, it's short video around 1 burrow of Gerbils in the wild Mongolian steppe, amazing they can survive in a desert really! See here - youtu.be/KmCZAK1soek?t=33
Although it is very sparse there, you can see tufts of grass, stones, small rocks, sticks, and dead(?) shrubs etc.
More vegetation here www.naturepl.com/stock-photo-mongolian-gerbils-meriones-unguiculatus-in-its-natural-habitat--the-image01514369.html

So, in a way you have to think.. is this for US or for THEM? We certainly don't want it to be like spoiling our children.

I'm not sure if you're speaking about the space they have, or the items put in the cage. But if you're talking about the space, I can't speak for everyone, but I bet most owners who give them large tanks aren't doing it for themselves but for the Gerbils (it's more work and expense for us after all! lol), and they have far more space in the wild. I have a 79 (US) gallon tank for mine, they can zip from one end of the tank to the other in a second (1.2m, ~4ft), if I had the money and space I would like to at least quadruple the size of the tank to give them some real decent running room, as well as more items for the environment.

Eva Waiblinger contributed to this article for the Swiss animal welfare - gerbilforum.proboards.com/thread/34343/gerbil-handbook-animal-welfare-translated (Original German article - www.tierschutz.com/publikationen/heimtiere/infothek/kleintiere/rennmaus.pdf )
Here's a small section I've improved on the Google/DeepL translation somewhat. (Imperial measurements added by me):-
Housing
Enclosure: Gerbils should be in spacious enclosures with deep litter, in which they can have a burrow system which will hold. Rodent wired cages, as offered commercially are too small and unsuitable for the animal-friendly keeping of gerbils because they are not deep enough. Rodent terrariums or aquariums are possible with a mesh top.
Also multi-storey enclosures such as the Gerbil villa (provider of small animal stables, see links), whose lower levels can have deep bedding are appropriate. A living space of several square meters would be ideal, which with a minimum of 40 cm [15.8”] or better 70 - 80 cm [27.6 – 31.5”] thick litter is provided for burrows. From an animal welfare point of view the minimum would be a terrarium of 140 x 60 x 60 cm [~4.6' x 2' x 2'] for 2 - 4 animals, but bigger is always better. That in larger terrariums it can cause sudden aggression is not proven.
----------------------------
As she is talking from the point of view of optimal welfare, it seems to me that her large minimum cage size is an ideal minimum, if you follow me .
For those who don't know Eva W., as well as studying and writing several papers about Gerbils and other animals, she has also looked after them at the Zurich Uni. She was the former Head of Companion Animal Welfare Department at (Swiss Animal Welfare) Schweizer Tierschutz STS from 2001-2013, and studied M.sc and PhD in Zoology at University Zürich. At the time of writing she is a biology and mathematics teacher in Switzerland.

[re post 1/7/19]

various research papers from renown laboratory and University sources on how gerbils behave in the wild, experimentation, and hearing about the many, many multiple failures with such over several years.

I haven't yet found any research papers that suggest or support the idea of a max cage size, though some are behind a paywall and I haven't committed to renting or buying them yet. But I will if you can tell me which paper, or author at least supports your theory. Hearing about failures in large tanks doesn't prove that it was due to the large tanks itself, you yourself have stated that it can happen for any number of reasons. Also I have read reports where people have sorted out declanning by going to a larger tank.

Things were great for a while, till the pair turned about 8 months old. Nothing changed, I did everything I always did, including always washing my hands with the same soap when going from cage to cage. They ended up getting into a nasty fight and de-clanned..
Interested to know more of the details about this situation, how long had they been in the 45gall tank? Were there separate areas in the tank? Do you recall it's dimensions?

Also, wouldn't Gerbils of that age (or any?) could possibly declann in any size cage?

Things were good for a while, then I started noticing that the gerbils in the 45 "acted a little wiggy" when they ran around the tank. One with one side would tense and get a little stiff when the other came over, and same with the other side of the tank with the other gerbil. At times, they would pause what they were doing and box a bit in the middle of the tank. I really didn't think much of it. A week later, I came home to a bloody mess and one of the gerbils was killed.

Sorry to hear that, that must have been horrible
Roughly how long were they in that tank for?
What size was the tank the breeder kept them in?

Already at two failures, I got another pair and tried again. Another failure.

Was the tank layout the same?
How long had they been in it?
What size tank did the pair come from?

Through the years, I've heard more de-clanning stories regarding gerbils in large tanks over 29 gallons than I have success stories.

Can you be certain that other issues didn't cause it? Maybe the group just weren't together to start with? Or could it be that you saw/heard of the large cage and put it down to that?
And particularly for new Gerbils, I wonder if the change going from say a minimum size cage from the breeder, shop or rescue ctr etc say, to a large cage is the problem? So I'm suggesting the sudden change in cage size (and location and owner) is a possible problem, rather than the absolute size itself.
I recently chatted to someone here who had declanning signs with her Gerbils, she later found out that by her handling a specific Gerbil of the 2, that was causing the problems! (even when handling both). IIRC they were ~2yrs old when this happened. If she didn't handle that one Gerbil, no problems! Lol, very odd.

but we also need to be responsible in following the rules of their society and in just how many proper sized tanks we can keep and ethically care for.

Agreed, except the rules of their society (in the wild) have no upper limit to their burrow size beyond what they can create and maintain. In other words, their is nothing in their rules of society that state a maximum cage size, if that's what you meant, if not, my apologies .

They are social, yes, but their “burrow-type” social society in the wild is not like a whole family clan piled up on top of each other in one big, huge burrow.

Actually, that's incorrect from what I've read.

Yes they are all together, 1 primary nesting place for the summer and another for winter, and yes multiple borrows for food storage and multiple entrances, but the clan sleeps in one area at a time, see here p219 (darn, meant to put a link to Companion Animal Care and Welfare: The UFAW Companion Animal Handbook again here, but that page is no longer shown ) for a couple of examples, and the papers blow for descriptions.

A breeding pair can be in charge of a clan of up to about 20 Gerbils (Journal of Mammalogy 14/8/09, Population Ecology of Wild Mongolian Gerbils Meriones unguiculatus, Liu, Wang, Zhong, Wan. FREE pdf! academic.oup.com/jmammal/article-pdf/90/4/832/2521917/90-4-832.pdf ).
Also previously (pay walled, Agren, Zhou & Zhong 1989 www.sciencedirect.com/science/article/abs/pii/0003347289900031?via%3Dihub ), an exert of that paper is here s469337723.websitehome.co.uk/gerbils/wild.htm#Social

Can you say what your source is regarding that they don't do that? (researchers name will do if you don't have an exact paper name).

Where trios and foursomes can work in tanks over 29-30 gallons- it gives them too much space, which can allow each gerbil to risk wanting to "claim" a territory, and this causes issues with them wanting to interact with each other. Gerbils do NOT need a lot of space to make a territory. 10 to 15 gallons of space is all they really need, even in the wild.

Sorry, but as fas as in the wild goes, that statement is flat out wrong, "The territory belonging to each group ranged from 325 to 1550m2 depending on group size, food availability and most importantly the body weight of the largest male gerbil." From that 1989 research paper by Agren et al. See an exert here - s469337723.websitehome.co.uk/gerbils/wild.htm , and also Wang et al have also found similar size ranges in their various papers, including Home-range sizes of social groups of Mongolian gerbils Meriones unguiculatus by Wang et al 2011.

For burrowing creatures, remember, my saying is " Snug is Safer"

That's just an opinion.
Snug and safe in the burrow, absolutely, as they would (mostly) be safe there in the wild, but that doesn't mean they shouldn't have plenty of space outside of their burrow, or to make a big burrow.

[re post 2/7/19]

As to links, any I saved back then was at least a decade and three computers ago.
I don't save now, but I do continue to take a few hours a week to continue to do research on my favorite four-legged fuzzy.

Then I don't understand how you've missed some of the old research I've recently dug up.
And as I mentioned previously, I'd be interested to read any research that supports your theory. Saying you've lost them is a poor excuse.

[re post 6/8/19]

Aug 5, 2019 11:26:33 GMT -8 shab said:

What do you think of the information based on veterinary/zoologist recommendations that suggest much larger habitats (55+ gallons)? Most of this information is currently only available in German, but the gist is traveling in English as well.

See STS Gerbil handbook I (partly) translated - gerbilforum.proboards.com/thread/34343/gerbil-handbook-animal-welfare-translated

In regards to this information, I suppose I would have a few questions to ask about that. One would be -- is this a "habitat" or "enclosure" meant for more than one gerbil, like perhaps a zoo or research center would have? In this way, there would be plenty of ideal acreage in order to create and perhaps maintain a society of gerbils with adequate distance and burrowing space that could mimic what they would do in the wild. If so, this is usually WAY more than the average animal lover can create and care for and I would never recommend this kind of thing in someone's backyard.

They are referring to cages in a home, not a semi-natural environment.

There's just been too much information written on it in regard to the issues it causes,

Nope, not that I've seen so far, and I have been digging around quite a lot, but if you can remember something about your sources then I'll gladly look again.

Its really not hard to find the de-clanning issues about this

I disagree with that, I haven't yet found anything supporting your premise. But, as I alluded to, I'm all ears!

In addition to what I've read and posted about above I have found these organisations/institutions that support the idea that 'bigger is always better'.

Cage sizes
Germany - Min rec. 100x50x50cm (2-6 Gerbils) ................... (250 lts, 55 imp gall, 66 US gall, 5000 cm2)
Austria - Min req. 80x50x50cm ........................................ (200 lts, 44 imp gall, 53 US gall, 4000 cm2)
Swiss - Min req. 100x50x30 (2-5 Gerbils) .......................... (150 lts, 33 imp gall, 40 US gall, 5000 cm2)
Swiss - rec 120x60x60 .................................................. (432 lts, 95 imp gall, 114 US gall, 7200 cm2)
Swiss Animal Protection - min rec. 140x60x60 (2-6 Gerbils) .. (504 lts, 111 imp gall, 133 US gall, 8400 cm2)
The Veterinary Association for Animal Welfare (Germany) 100x50x50 for a pair, plus a 30cm topper

The following rescue centres/charities in the UK (although all these have lower min's than the above, they support bigger is better) :-
RSPCA, Bluecross, Raystede, Pets corner, Woodgreen animal ctr, Gerbil and Rodent Rescue UK.

And from this forum, at least a few breeders too, who I won't name in case they want to stay out of this discussion. Plus a US breeder (Wild prairie Gerbils) not (AFAIK) on this forum ( wildprairiegerbils.weebly.com/gerbil-care-basics.html )

Also, and I appreciate this isn't solid info, but in Germany (as shab alluded to), and in their rennmaus.de forum it is widespread good practice there to consider a minimum cage size as 100x50x50cm (66 US gallons), with a decent size being 140cm and upwards! An English lady recently posted about her cage and Gerbil colours there www.rennmaus.de/community/thema/173485-haltung-in-england-abgetrennt-aus-farbfrage/?pageNo=1 , with people noting that the cage is only 60x30cm (~2'x1') floor area (1800 cm2), people were wondering if it was just a transport cage! When they found out it wasn't they seemed genuinely shocked that she had such a small cage for them! She was getting quite a bit of heat about it (although as far as I could tell it was polite).
Bear in mind, that like here, some of them at least will be breeders and experienced owners, not just animal welfare advocates.
(Btw, incase you use Google translate there, haltung does NOT mean attitude in English in the context it is used there, more like housing, or enclosure, just to avoid crossed wires! ).

nazasaki
That declan sounded like a nightmare (I've read your 2 threads about it), but any number of things could have caused that, and it seems likely it's not down to the large tank. Some people have sorted out declans by going to larger tanks! You yourself stated that they were fine for about 9 months (Feb-Nov) in the bigger cage "They LOVED the space", so if it was the large cage space alone then surely problems would've happened much sooner? Perhaps it was some minor change in their cage or nearby environment that set them off? Maybe the tank was un-intentionally, subtly semi-partitioned, creating 'separate' territories? Just guessing of course, but it's worth noting that in the wild they have far more space then largest tanks etc that we could provide.
Also worth noting that in Germany, Austria and Switzerland it is common place to have large tanks, w-a-y above the so called ideal max of 20gall for a pair, see my notes on tanks sizes above.

It appears that tuftsnfluff has (mostly) assumed the de-clann was down to the cage size, and you only really blamed the large tank when she mentioned that idea.[/font]