Gerbil Housing ~ Tank Sizes
Recommended tank sizes for gerbils
When deciding on accommodation for your gerbils it would be wise to remember that in the wild, Mongolian gerbils are inveterate burrowers and live in complex burrow systems that may stretch for several metres. They are not solitary creatures but live in fairly large communities. As well as running and burrowing, the gerbil also likes to stand up to view his environment. In this fully erect posture a gerbil may be 12 cms or more in height. Therefore when choosing and purchasing suitable accommodation we should bear these facts in mind.
When looking for information on recommended tank sizes for gerbils, there are several sources available. On the internet there are several gerbil websites, all of which give specific tank sizes for varying numbers for gerbils. However all of these websites seem to disagree on definitive sizes, so a new gerbil owner may be left wondering which information is correct.
So what tank sizes do gerbil websites recommend?
Of course I cannot cover every gerbil website out there, but I will give a review of some of the major ones around the world on their recommended tank sizes for gerbils.
The American Gerbil Society Care Guide
The AGS website and care guide is a popular online guide for gerbil enthusiasts, and most smaller personal websites of gerbil owners often quote the care guides tank sizes in their own websites guidelines on gerbil care. This can also be said for many gerbil forums too, and all too often I have seen replies to posters quoting the A.G.S care guidelines on tank sizes. These guidelines on tank sizes read as follows:
10 gallon tank 1 or 2 gerbils
15 gallon tank 3 gerbils
20 gallon tank 4 gerbils
30 gallon tank 6 gerbils
In essence they are recommending just 5 U.S. gallon per gerbil, and are saying that ten U.S. gallons are fine for a pair of gerbils. Now while I think this is fine for temporary accommodation, or maybe a hospital tank, I certainly don't think it's adequate to house two healthy adult gerbils in it, and it's certainly too small to breed gerbils in, especially if you are truly putting your gerbil's welfare first and foremost.
The National Gerbil Society Website (U.K.)
On this website in their “general care” leaflets it states that, “One of the better and least expensive forms of housing is a simple aquarium of glass or plastic. For a pair of Gerbils a 15" by 12" by 10" tank is ideal.” This is around 6.5 imp. Gallons or 3 imp. Gallons per gerbil and to my mind is very small to house a pair of healthy adult gerbils, and I think it generally gives out a bad message to new gerbil owners when choosing a tank to house their new pets in. It seems to lend weight to the ‘throw away’ pet image that gerbils have got, and surely a minimum standard of tank size as low as this belongs in the last century? It may be a minimum standard in the laboratory, but surely we should be advocating more room for our chosen pet?
Gerbil information page
This is a large, very informative Dutch based website and they recommend that tanks should be used and not cages. They suggest that the minimal required measurements for two gerbils are 30 x 60 cm. (approx. 12x24 inches) surface area. While a family consisting of 4 - 8 gerbils needs a surface of 40 x 100 cm. (approx. 16x40 inches). The height of the container needs to be at least 30 cm. (approx. 12 inches)
So here we can see if we convert the figures to imperial gallons by including the minimum height measurement given, they are saying that the minimum size tank for a pair of gerbils should be approx. 12.5 imperial Gallons, and that you can house 4-8 gerbils comfortably in a 27 imperial gallon tank. While 12.5 imperial Gallons (approx 15 U.S. Gallons) seems a reasonable minimum recommendation to house a pair of gerbils, 27 Gallons for 8 gerbils may prove to be a little bit cramped!
The Mongolian gerbil website
This is another Dutch based website and recommends a surface area of at least 800 cm2² (124 sq inches) per animal. And that the height of the cage needs to be a minimum of 30 cm. (approx12 inches) this works out approx at 28x28cm (approx. 11 x 11 inch) per gerbil, or roughly 5 imperial Gallons per gerbil if you are giving the tank 12inch in height. It also says that when you want to keep more than 4 gerbils together, you can reduce the surface area to 500 cm2 / 77.5 sq inches, and if we apply 12 inch minimum height to this it would work out at approx 3.5 Gallon per gerbil. After saying this it then goes on to recommend a surface area of 30 x 60cm (12x24 inches) for two gerbils, 40 x 60 cm (16x24 inches) for 3 gerbils and a surface of 40 x 80 cm (16x32 inches) for 4 gerbils would be required. So if we apply the minimum recommended height of 30cm (12inch) to these values, we then find that for 2 gerbils can be housed in approx. a 12.5 imperial gallon tank, 3 gerbils in approx. a 17 imperial gallon tank, and 4 in approx. a 22 imperial gallon tank. So although the website quotes the absolute minimum of approx 5 gallons per gerbil, similar to the A.G.S. website, it then allows more ample room in its later figures for housing gerbils.
This is a detailed and informative site of a breeder from Quebec City, Canada, and on their housing page they explain that the well known figure of 10 U.S. gallons for a pair of gerbils seems very small indeed and the bigger you can make it beyond these values, the better! They then quote some size guidelines from the Canadian Council on Animal Care (C.C.A.C.) from their guide to the care and use of experimental animals and again questions are raised as to how small their given environments are.
So where do these figures on cage sizes come from?
In lab animals
In lab management welfare it is assumed that there are critical measures of cage floor and cage height below which the physiology and behaviour of lab rodents are aversely affected, which in turn will affect the well being of animals and the outcomes of research data. There have been many studies in all common rodent species to evaluate the effects of space on population dynamics and also into environmental enrichment, as this is really important when conducting research into animals and each species will have different cage size outlines to promote optimum well being in the animals. As well as this, cage space recommendations are the results of surveys of existing conditions within labs, and professional judgment and consensus of the people who work with these rodents on a day to day basis. In America, there exists "The Guide" from the national research council, which provides space recommendations for rodents. In other countries space recommendations have been formulated (such as the Canadian Council on Animal Care, and the European council)
So what are the minimum size recommendations for gerbils in labs?
There has been quite a bit of research in gerbil stereotypical behaviours (repetitive behaviour patterns with no goal or function) spanning over 20 years because these behaviours these can affect the outcomes of research into the animal being studied. Initial research began in 1990 when Chris Weidenmayer started his PhD at the uni. of Zurich. These studies led to the discovery that gerbils that grew up in their parent's complex burrow systems do not develop stereotypical digging. For the laboratory however, artificial burrows that reduced the complexity of the burrows were designed (these are basically a tube with a nestbox attached) by Eva Waiblinger PhD who is a companion animal welfare specialist at the Swiss animal protection. Eva however recommends that although these are for lab use, for pet gerbil housing, she would discourage the use of artificial burrow systems, such as habitrail, rotostack or similar. This is because gerbils are inveterate burrowers and If you analyse burrowing behaviour more closely, it becomes clear that any artificial man made burrow, is just a crude copy of the original, and will never be able to mimic its complexity or flexibility. If you want to truly make your gerbil happy, let them dig a burrow. That is their "job" and is one of their main occupations in the wild besides collecting food and socializing. She recommends that wherever possible, gerbils should be kept in large, deep substrate tanks (at least 100x50x50cm for 2-3 gerbils, and 150x60x60 cm for 4-6 animals, with at least 30cm deep bedding) and should be left to dig their own burrows. For gerbils in labs they trialed the artificial burrow systems in a laboratory cage type IV [38 x 58 cm x 20 cm height] (15x23x8). (approx. 10 imp.Gallons)
Many countries have their own guidelines for the care and welfare of their laboratory animals. In America there exists "The guide" from the National Research Council. Although "the guide" has recommended sizes for rodents, there are no specific guidelines for the proper housing for gerbils, however In the CCAC's (Canadian Council on Animal Care) guide it states that "Any cage suitable for rats and golden hamsters is satisfactory for gerbils. As gerbils often stand erect on their hind legs, the cages should have a solid bottom, with floor to lid height at least 15 cm. A monogamous breeding pair requires a floor area of about 700-900 cm2 and gerbils caged in large groups need about 100 cm2 floor area per animal (Norris, 1987)". So if we take these values and convert them we find that in Canadian laboratory conditions, a breeding pair of gerbils should be given approx 700-900 cm (approx 108.5-139.5sq inch) and a minimum lid height of 15cm (approx 6inch) These values would give us tank sizes of approx 10 x10 x6 inch, to approx 12 x12 x6 inch or around 2 Imperial Gallons to approx 3 Imperial gallons. These figures to my mind are appallingly low for any research to be conducted accurately and 6 inches of height is simply not enough height for a gerbil's environment, even if we include the smallest amount of bedding into their environment.
However in Europe, the council of Europe has detailed guidelines for gerbils. In these guidelines they state "Gerbils need comparatively more space than other rodent species in order to allow them to build and/or use burrows of sufficient size. Gerbils require a thick layer of litter for digging and nesting or a burrow substitute, which needs to be at least 20 cm long. Consideration should be given to the use of translucent or tinted enclosures and inserts which permit good observation of the animals without disturbing them. The same principles regarding quality and quantity of space, environmental enrichment and other considerations in this document should apply to containment systems such as individually ventilated cages (IVCs), although the design of the system may mean that these may have to be approached differently."
So we can immediately see from the above table that gerbils in European laboratory conditions have access to larger quarters than is given in Canadian laboratories. The behaviour of the gerbil has been better researched and allowances for 20cm long artificial burrows are recommended. The above table suggests that for a breeding pair of gerbils that the absolute minimum enclosure size should be around 1200cm2 (186 sq inch) and the minimum height should be around 18cm (7 inch) This works out at approx. 14x14x7 inch which is roughly around 5 Imperial gallons. These figures from laboratories are absolute minimums, and as mentioned earlier, that in reality they may be using larger sized housing for their gerbils used in research (such as the type 4 lab cages used when trialling the artificial burrow systems) but we can glean from these figures that they maybe the sources where the A.G.S and the N.G.S societies are getting their current guidelines from.
Where else do cage size measurements come from?
Cage size recommendations exist in most countries for animals in pet shops, and are based on current animal welfare laws in that particular country. Also in some countries like Austria, even for pet gerbils kept in homes there exists a minimum cage size. For places like Austria it is a law that in a cage with grids you need 60x30 x40 cm, and when keeping them in a tank you need 80x50x50cm. It is also law in Austria that gerbils must have access to a sandbath. Countries like Germany it is recommended that 100x50x50cm for 2-6 gerbils would be best, however this isn't fixed by law. In the UK although there isn't any sizes stipulated for pet gerbils, there exists the Animal welfare act, which allows individual councils to enforce certain laws before they grant a pet shop license. Some councils, but not all, have minimum cage sizes for animals housed in pet shops, and these may vary from council to council.
These laws allow the individual to report pet shops that have their animals in poor or inadequate enclosures, and rather than complaining to the pet shop itself, it's often wiser to report the premises to your local council, who have the rights to revoke their pet shop licence.
However not all countries have such strict animal welfare rights and countries such as America, in their animal welfare act which applies to pet shops, it only stipulates that the housing or caging of animals at pet shops require that animals be provided with adequate space to stand up, sit down, and assume natural postural positions. Some states also require all housing to be constructed in a manner that prevents injury to the animals housed within. So basically as long as the animal can sit down and stand up without discomfort, then the size of tank or cage that allows this is ok.
So to sum up; tank sizes are only basic guidelines and usually state the absolute minimum sizes for an animals well being. Some countries have larger minimum guidelines than others. In the US it is the AGS that in their opinion recommend that to house 1-2 gerbils in 10 U.S. gallon tanks is fine. In the U.K. it is the opinion of the N.G.S. that gerbils can be housed in 6 imp.Gallon tanks. In other countries they recommend larger housing environments for their pet gerbils. In some of these countries these minimum guidelines are law for pets, the pet shops and in the laboratory.
Please enter your measurements in inches.
Results based on an empty tank and do not account for displacement caused by rocks, substrate, toys, etc.
CCAC, Guide Vol. 1 (2nd Ed.) 1993 -Chapter VI - Social and Behavioural Requirements of Experimental Animal
Council of Europe- APPENDIX A-OF THE EUROPEAN CONVENTION FOR THE PROTECTION OF VERTEBRATE ANIMALS USED FOR EXPERIMENTAL AND OTHER SCIENTIFIC PURPOSES (ETS NO. 123) -GUIDELINES FOR ACCOMMODATION AND CARE OF ANIMALS (ARTICLE 5 OF THE CONVENTION) APPROVED BY THE MULTILATERAL CONSULTATION
Refinement of Gerbil Housing and Husbandry in the Laboratory- Eva Waiblinger and Barbara König Animal Behaviour, Zoologisches Institut, Universität Zürich, Zürich, Switzerland
Guide for the Care and Use of Laboratory Animals-Institute of Laboratory Animal Resources Commission on Life Sciences - National Research Council
Modifications to Husbandry and Housing Conditions of Laboratory Rodents for Improved Well-being- Abigail L. Smith and Dorcas J. Corrow