Choosing Mice

By Cait McKeown

1. Where are the mice housed?

a. If they are near to prey, this is a fault by the staff since prey and predator are not supposed to be housed in view/short range (smell) of one another for peace of mind of both animals, especially prey.
b. Is the tank near a window or in a source of heat/draught? If so, the mice may be suffering the effects of these conditions and their health and immune systems may have suffered.
c. Are they on view or tucked away in a corner as if the shop is not bothered about them?

2. Have the mice been provided suitable housing?

a. Are they in a plastic or glass tank rather than a wire cage? If they are in a wire cage are the bars narrow enough to prevent escape?
b. Have they been given suitable toys and things to keep them safe and entertained? A barren tank will be boring for the mice, which may cause them to become depressed and inactive.
c. Is the substrate and bedding of a suitable kind? If there is no bedding provided ask for justification. Make sure that the substrate (wood shavings, aspen, shredded paper, corn cob, CareFresh etc) is clean and shows no sign of damp or mould. Avoid any mice kept in these conditions and alert the pet shop to their problem.

3. Have the mice been provided with suitable/enough food and water?

a. Is the food bowl full? If it has been kicked around by the mice it can be hard to tell – but then again if it has been kicked around the staff should notice and fill it up.
b. Is the water bottle full? If soluble vitamins have been added to the water it is normal for it to be a yellow colour, but it should still be clear and not murky.
c. Are any of the mice fighting over food? This usually happens if there is not enough food, although it can happen over a particular favourite treat. The two should be fairly easy to tell apart by the amount of food visible in the tank, since mice do not hide their food in stores like hamsters.
d. Is the type of food provided of a suitable variety for mice to eat? Although mice eat many things, there are inevitably some things that they should not eat too much of and that can cause problems. A boring commercial mix is usually supplied by shops so take note of any special diets or supplements as an indicator of good standards of care.

4. Are food and water containers/tanks clean and hygienic?

a. Is the water fresh and clean? Water should be changed every day and there should always be much more than would be necessary. In a large tank two water bottles may be used.
b. Is the bottle clear and not murky or cracked? If a bowl is used is it full of shavings/not providing an adequate amount of water? Cracked and dirty bottles can be a breeding ground for bacteria that will make the mice ill.
c. Is food soiled by faeces etc? Food should be edible and appealing rather than just about survival: you can always ask staff what they feed their mice and why.

5. Is there adequate ventilation?

a. Are the tanks stacked so that no air can circulate to the mice?
b. Is there an obvious ammonia build-up? You will be able to smell this and it will probably be more obvious with the male mice than the females. This indicates poor ventilation and slack cleaning out.
c. Are the tops of any tanks covered, impeding airflow? Again, ammonia can harm the respiratory system of a mouse and air should be allowed to circulate in the room where the tank is to prevent breathing problems in the mice.

6. Are males and females separated?

a. Do the staff know how to sex the mice? They shouldn’t rely on the breeders that supply the mice to pet shops, since they can be wrong, and double-checking is always the way to go. Try to check yourself as well instead of taking their word for it. It’s all very well if they can tell you how to do it, but practical proof is best – I have met assistants who know the theory but can’t actually sex mice in reality.
b. Don’t take any excuses about the shop not being able to guarantee the sex of the mouse, although most have this get-out clause. Mice can be sexed a long time before they are old enough to be sold.
c. If they admit to keeping the males and females together, don’t even bother! From four weeks the sexes should be kept separately to avoid any pregnancies. Ask them why they don’t separate the mice (I would certainly like to know, since there is no logical reason) – one pet shop told me it was because ‘the mice aren’t usually here long enough for us to bother’! NB: This means they were selling possibly pregnant mice/mixed sex pairs to people with no breeding experience, all for the sake of spending less than five minutes sexing the mice – it’s that quick to do.

7. Are staff knowledgeable?

a. The best way to tell if staff ‘know their stuff’ is to read up about mice before you go to get one, so you will be more likely to spot a blagger. Some assistants will make out that they know about the animal they are selling when they don’t, and sound convincing.
b. If staff give you advice that you are unsure of, get a second opinion or go elsewhere. You don’t have to take their word for it. And make sure you put them straight if you know for a fact they are telling customers the wrong information.
c. If the shop has a ‘specialist’ person who deals with mice, make sure you speak to them and ask to wait if they are busy for a few minutes. That way you will be able to get relevant advice and speak to someone who knows more than a general assistant. Full-time staff are also usually more knowledgeable than part-time staff.
d. Do the staff know where the mice came from (location, breeder, stock) or anything about their bloodline? If you plan to breed a mouse you will need to know about its parents, and perhaps siblings, although in a pet shop these are usually for sale along with the mouse you are interested in.
e. Does the shop provide an information leaflet/booklet free of charge about mice? This is a good sign that they are concerned about what happens once the mice leave the shop, but the assistants should also be able to answer questions and not just refer you to any handouts.

8. Does the shop have a good reputation?

a. It is always good to start somewhere you have been recommended, or that has a good reputation. However, just because a place is bigger, or part of a chain, does not mean the staff are more knowledgeable or the animals are better cared for.
b. The shop may give you a 48-hour guarantee (I know this is the policy of some Garden Centres). This means that you can return this mouse within this period if you have good reason. Just remember, a mouse can begin to starve/die of dehydration within eight hours without food or water, so make sure you look after your mouse properly. This guarantee is probably best used to return aggressive mice or mice who do not get along with your original colony.
c. Buying your pet at a weekend may be the most practical day for you, but it will also be the same for hundreds of other people. In other words, try to buy your mouse on a quieter day when the shop is not so busy and you can have the assistant’s full attention for as long as you need it. Otherwise they may try to hurry you or you may feel pressurised and make an unwise decision. Buying on a less busy day will also give you time to inspect, handle and assess the mice as well as ask all the questions you need to.

9. Are the mice old enough?

a. Are there nursing mothers and pinkies in display tanks? – if so be very wary. These mice should be kept in a quieter place where they can feel safe and not be disturbed, not in a busy shop.
b. Are the males above four weeks and the females above five? Do you trust how old the shop tells you they are (or do they look younger/older)?

10. Are the mice healthy and active?

a. Do the mice have nice shiny smooth coats?
b. Are the mice’s eyes bright and inquisitive?
c. Are their tails free from kinks and wounds?
d. Is there any sneezing in the tank, even if it is not the mouse you are interested in? If so, look elsewhere.
e. Have the mice been socialised? i.e. can you hold them without them struggling to get away/jumping? (if they are jumping a lot then they will be young mice and you will be better waiting until they are a week or so older – you could always reserve the mouse and then take another look).
f. Is the mouse’s back end free of dirt, debris and faeces?
g. Does the mouse have clean eyes, ears etc without any discharge?
h. Is the mouse wound and lump-free?
i. Is the mouse over or under weight?
j. Does the mouse run and hide in the corner or stand up to sniff your hand? The more curious mouse may make friends with you more quickly and climb onto your hand. However, shy mice are not to be discounted and may prove just as friendly after they get to know and trust you.
k. Does the mouse walk normally? If it limps or spins in circles then there is something wrong. ‘Waltzing’ mice tend to turn in circles and have a dizzy movement, which is not normal and healthy, so avoid these mice.
l. A mouse’s breathing will be fast, but should not be noisy. It may also feel as if it is quivering when you hold it, but this is simply its heart beating (around 600 times a minute).
m. Is the faeces formed? Mice with diarrhoea may be ill or fed too many greens, but are best avoided. At this point it is worth noting that mice may defecate/urinate when they are nervous, so if they go to the toilet when you hold them for the first few times this is nothing to worry about.
n. Does the mouse appear to be missing fur or whiskers? If so, it may be that the mouse itself is doing the ‘barbering’, or that it has been housed with another mouse who is doing it. If there is one mouse with whiskers when none of the others have them, then this mouse is the culprit and should not be purchased. This habit is hereditary and so it would probably not be wise to buy any of the mouse’s siblings either.
o. Are any of the mice scratching excessively? If so avoid them as they may have a mite or lice infestation.

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