Mouse FAQ - DRAFT 2
Angela King
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I'm compiling a pet mouse FAQ - would anyone else like to contribute or
comment? Perhaps people could write (& sign) sections in areas which
particularly interest them. I've started off with a couple of sections below.
Please email me if you'd like to add anything or comment.
Please note that this is VERY draft & therefore incomplete. Hopefully
the finished product will be quite comprehensive.
Standard disclaimers apply about not being a vet, etc.. This FAQ is based upon
the experience and understanding of the contributors, NOT on any veterinary
qualification.
KEEPING MICE AS PETS
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1.0 Why keep mice as pets?
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They are very happy and playful, active creatures. They are great fun to
watch. Some fancy mice are extremely pretty. They get to know their owners
and will come to take treats off you, climb onto your hand and run all over
you. They are very easy to keep, undemanding pets.
1.1 How many should I get?
--------------------------
At least two - mice are social animals and it is *very* unnatural for them to
live alone. Single mice are generally bored, lonely and miserable, and they
do not make good pets as they tend to spend more time sleeping or hiding in
the nestbox than mice kept in groups. With a single mouse you also miss out on
the fun of watching mice play together and groom each other. Having said that,
you CANNOT introduce an adult male mouse to another male - if
they do not fight to the death, one is likely to die from the stress of the
experience. So adult male mice which are aggressive have to live alone unless
they are used for breeding.
1.2 How old should they be when I get them?
--------------------------------------------
Baby mice are weaned from their mother at about four weeks old, but they
benefit a lot from staying with their litter mates for another week - the
disruption of leaving both mother, sibilings and home in one day is a lot to
cope with. Ideally they should not leave the litter before 5 weeks of age.
They are not fully grown until at least 12 weeks of age, although many mice
take longer than this to reach full size.
1.3 Can you ever keep males together?
-------------------------------------
Yes, if they are introduced very young (under 5 weeks old), and preferably
when they are from the same litter. Sometimes even established groups of males
fall out, though - you have to watch them carefully. Neutered males can live
together or with females.
1.4 Don't mice smell?
----------------------
Males smell a lot - they produce a musk-like substance. Females smell much
less and many people find they cannot smell a couple of females at all if they
are kept clean. Mouse cages need to be cleaned out at least once a week to
stop them smelling offensive.
1.5 How do you introduce adult females?
----------------------------------------
Clean out the cage thoroughly, remembering to scrub all toys and cage
furniture to remove the smell of the established mice. Since they recognise
their own territory by smell, they will be less defensive over territory that
doesn't smell like it is their own. Dab each mouse (old and new) with
something smelly like perfume or vanilla essence, to confuse their scents. Put
all the mice in the clean cage with an extra-tasty feed. There will almost
always be some squeaking and occasionally tail biting while a hierarchy is
established. If any female mouse is vicious towards the others and inflicts
serious wounds then do not breed from her - she will pass on her nasty
temperament to her children.
1.6 Can male mice be neutered?
------------------------------
Yes. Traditionally the problem with operating on mice was that they didn't
survive the anaesthetic. However, mice can cope very well with Isoflourane
anaesthesia, and neutering (castration) is a relatively simple operation.
Allow a couple of weeks for fertility and hormones to subside. Susan Randlett
and Ted Parsons from Alaska have had many mice neutered over the years and
said that:
"We have had some success keeping sibling males together from birth, but
at about four months age, fighting escalated to the point of tissue
damage (tails, ears, etc.). Rather than separate the boys, we tried
neutering. Our Vet uses isoflurane as an anesthetic, and no ill effects
have occurred. The anesthetic also permitted various other surgical
procedures on mice of 15-50 grams (wound repairs, etc.
We've had over a dozen of our males neutered, with no evidence of
complications. We checked with a large US Veterinary College about
other methods of birth control for mice. The professor said that
vasectomies are unsuccessful due to subsequent cyst formation; there is
no contraceptive for oral use on mice. After neutering,
aggressiveness generally diminishes, although it takes a while for
testosterone levels to go down, as it is stored in the animal's fat.
Also, the mouse remains fertile for a week or two. We have males
living with females, with each other, and unrelated males living
together thanks to neutering.
One of our favorite male mice used to get so excited that each
out-of-cage experience ended with one of us getting bitten. Since his
surgery, the biting has stopped, although he is still quite excitable
and we have him in solo houseing. One gratifying benefit of neutering
is that the male smell is substantially reduced!"
1.7 How should you pick a mouse up?
-----------------------------------
With a strange or nervous mouse, the safest way to pick it up is to grasp the
BASE of its tail (not the tip) firmly, lift its bottom up slightly and slide
your other hand under the mouse, palm upwards. You can then lift your hand up
with the mouse sitting on it, but keep hold of the tail unless
you know the mouse is calm. Most pet mice will not jump from heights of more
than a foot or so, but very nervous ones might - so keep a grip on the tail
until you're sure. Don't hold the mouse tightly round its body - this
will scare it and could hurt it.
In some cases you might see people picking mice up by the base of the tail and
holding them, dangling, upside down. This is not really cruel as it doesn't
hurt them, but not surprisingly most mice don't seem to like being handled like
this - it is more comfortable for them if you support the body with your hand
as described above.
1.8 How do you tame/socialize pet mice?
----------------------------------------
Handle them often and gently, and bribe them with food. One good method is to
take all food out of the cage for a few hours, then sit down to watch TV or
read a book with the mouse cage by your side. Take a spray of millet or a
handful of cockatiel seed in your hand and just leave the hand in the mouse
cage while you concentrate on something else. The reason for using these
particular treats is that mice love the seeds, but since they are small they
have to keep coming back for more. Do this as often and for as long as you can
stand - it may take several attempts before the mice start to take food from
you, but eventually they will start to climb over your hand and perhaps try to
climb up your arms.
Angela King
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MOUSE HOUSING
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2.1 How much space does a pair of mice need?
---------------------------------------------
Mice don't need very much space to survive, and many breeders and labs keep
pairs or trios in boxes or cages with floor dimensions around 9" x 16".
However, it is easy and costs very little to give your mice more than the
bare minimum of space to live in - 'survival' is not good enough for our pets.
Whatever cage you use, it should be
tall enough to allow the mice to stand up on their hind legs and sniff the air
- say 6 inches. But taller cages make it easier for you to look in from
outside the cage and watch your mice.
What really matters to the mice is floorspace. Long, thin cages (eg tanks)
are better than short, wide ones as they allow more space to run. For
permanent housing a minimum of 2 square feet of floorspace will provide a very
good home for anything between 2 and 8 mice. This might be a 2' long tank, or
a wire cage with several levels.
2.2 What sort of housing is best?
---------------------------------
I have mice in a variety of cages - glass tanks, plastic cages and 3-storey
wire hamster cages. My experiences are as follows:
WIRE CAGES (this goes for bird cages too) - BAD POINTS:
1. If you can get a finger through the wire, a young mouse can get out
(unless it's a very large adult buck). Single mice are more prone to try
to escape than mice which live in groups. Sometimes a mouse may try to
squeeze through the bars, get stuck halfway and hurt itself.
2. If any levels in the cage have wire floors or ladders, they will be
corroded by mouse urine and your shiny new cage will be dingy and impossible
to get clean within a year.
3. Bird and hamster cages usually have only one or two small doors. This can
make it hard to catch mice - if you have to chase them around the cage to
catch them, they will get panicked & upset. You need to be able to reach ALL
areas of the cage easily.
WIRE CAGES - GOOD POINTS:
4. Mice love to climb & wire-sided cages provide good opportunities for this.
5. Great ventilation - mice are prone to respiratory problems which are
aggravated by ammonia build-up in poorly ventilated cages.
6. Large hamster cages (multi-storey are the only ones worth considering) are
fairly cheap & easy to find.
7. Multiple-storey cages allow the mice plenty of floorspace whilst taking
up little of yours.
GLASS TANKS - BAD POINTS
1. You have to be careful cleaning them - I've found the best method is to
shovel out used bedding in a dustpan, scrape the corners out with a paint
scraper, them spray the inside with disinfectant spray. After this you need
to wipe over with clean water so the mice don't have to inhale disinfectant.
2. Obviously, heavy & they break if you drop them.
3. To provide adequate ventilation you need to make a lid of wire mesh,
no more than 1/2" square or youngsters will squeeze through (yes, even large
show mice up to 8 weeks old can squeeze through 1" x 1/2" mesh) and they can
jump a long way up to grab the wire. The easiest way to make a lid is to staple
the wire to two battens of wood which fit tightly over the longest sides of the
cage. If you can be bothered to make a proper frame, it looks nicer!
4. Mice can't climb up the sides, so you need to put in lots of toys &
'furniture' like pieces of wood for them to climb over - they really love
scrambling over different levels.
GLASS TANKS - GOOD POINTS
5. No danger of escape as long as you make a suitable lid.
6. Bedding can be piled really deep so the mice can burrow through it and
play in it without hoofing it all over your carpet. They love deep bedding,
and they love throwing it out of the cage.
7. Keeps the smell in as well as the bedding!
8. You can easily watch your mice being excessively cute and playing in the
bedding etc..
9. Warm and protected from draughts
10. Cheap & easy to find second-hand; leaks don't matter for mice (but cracks
may be dangerous).
11. Lots of floorspace to arrange toys and furniture on.
PLASTIC CAGES
These can be either plastic tanks or boxes, or modular systems designed for
hamsters such as Habitrail, Rotastak etc.. I'm informed by hamster people that
these aren't much good for hamsters since they're vulnerable to chewing & too
small for an adult Syrian hamster. They're probably better for mice since
mice generally are less intent on escape than hamsters, and are smaller.
BAD POINTS
1. Modular systems can be fiddly to dismantle and clean.
2. Ventilation may be inadequate - a few holes bored in the plastic will
not induce much air circulation. Better to replace the lid with wire mesh if
ventilation is poor, or fit a mesh panel.
3. If you have a determined chewer it may escape.
PLASTIC CAGES - GOOD POINTS
4. Square or rectangular plastic tanks are the easiest thing in the world to
clean - just stick them in the sink.
5. Light & portable.
6. Mice love tunnels & hiding places & exploring, so modular systems provide
a lot of opportunities.
My considered favourite is the glass tank because you get so much more out of
your mice when you can see them very easily. Whatever cage you use, do situate
it at eye level - when you can see your mice easily it is easier to interact
with them & get them tame.
Angela King
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MOUSE DIETS
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3.0 What should I feed my mice?
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READY-MADE FOODS
A standard rodent mix containing an assortment of grains is adequate for most
adult mice. This does not mean it is nutritionally the very best your mice
can have - since it is designed to suit various rodents it will not be
tailored exactly to mouse requirements. However, mice enjoy picking amongst
the food and will normally take only what they need without gorging themselves.
Many of these mixes are made for hamsters - fine if your mice stay slim, but
often too fatty for those with a big appetite.
Laboratory pellets provide a complete and vitamin-enriched food, but a diet
of pellets is very, very boring and since many mice are picky eaters you may
have trouble persuading them to eat it.
HOME-MADE MOUSE FOOD
If you are prepared to go to a little more trouble, a home-made mouse diet can
be far cheaper than ready-made foods, and more nutritious as well. You can
vary the following to suit the waistlines and preferences of your mice:
*1 part by volume cooked wholegrain rice (you can cook large batches & freeze
it for convenience)
*2 parts crushed barley or oats, or a mixture (or porridge oats)
*1/2 part millet or cockatiel seed
*1/2 part molasses - packed full of vitamins, and sweet too, so it binds
the foodtogether AND the mice like it.
Additional nutritional supplements can be added if desired:
*1/4 part Brewers' Yeast flakes - B vitamins to keep them healthy & happy
*1/2 part wheatgerm
*Cod liver oil according to manufacturer's recommended dosage.
This mixture is adapted from the rat diet designed by Debbie Ducommun.
Sunflower seeds can be given as treats, except to fat mice.
STALE BREAD!
Stale wholemeal bread makes a very good mouse food, and lots of show mice live
on very little else. It should be allowed to dry out thoroughly first, then
soak it in water (or skimmed milk for babies/mothers, or stock/gravy for a
change of flavour). The reason for allowing the bread to go stale first is
that some mice react badly to enzymes in fresh bread which are killed by
the staling process (they get spots & itchy skin).
FRUIT & VEG
Small amounts of fruit and veg are a valuable addition to ANY of the above
feeding regimes. Only feed TINY quantities of green veg (lettuce, cabbage,
broccoli) at a time - too much causes diahorrhea, and mice can get dehydrated
by this very quickly.
Crunchy fruit & veg such as carrots & apples provide vitamins and an interesting
texture, and do not usually cause diahorrhea.
Avoid acidic foods such as citrus fruits and onions which could irritate the
digestive system.
Mice love garden peas!
All fruit & veg are best fed raw to preserve nutritional content.
SPECIAL NEEDS - MOTHERS & BABIES
Supplement feed with natural yoghurt, bread soaked in skimmed milk (or water
& powdered milk, which is cheaper), small pieces of cooked meat etc..
Give lots of millet & sunflower seeds.
ADDITIONAL TREATS
Wholemeal pasta, esp. wriggly spaghetti, small amounts of leftovers, live
mealworms (not the giant ones - they frighten the mice!), sunflower seeds etc..
3.1 Are there any foods I _shouldn't_ feed my mice?
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FOODS TO AVOID
*Anything fatty which DOESN'T have compensating nutritional value (eg sunflower
seeds & millet are rich in vitamins & protein, but chocolate isn't!).
*Peanuts are fattier and less nutritious than sunflower seeds.
*Chocolate can be toxic in large amounts
*Acidic fruit & veg (citrus fruits, onions etc.)
**Anthing you wouldn't eat yourself because it might give you food poisoning -
mice are susceptible to salmonella & other bacterial infections too!
*Unwashed fruit/veg which might carry pesticides etc - wash it first.
3.2 What should you feed a very fat mouse?
-----------------------------------------
FAT MICE
Some mice are prone to obesity - particularly red and sable coloured ones.
Often the top half of the mouse looks fine, whilst a sprawling belly spreads
out from underneath.
Obesity will shorten the mouse's lifespan & make it more vulnerable to cancer,
respiratory trouble etc.. If you want to put your fat mouse on a diet, cut out
all oily seeds (peanuts, sunflower seeds, millet etc), dairy products, fatty
treats etc.. If possible, keep her on a diet of home-made mouse food (see
above) and/or soaked staled bread, with lots of fruit & veg. You can give
her vitamin supplements to make sure the change of diet doesn't leave her
with any deficiencies.
3.2 My mouse has itchy sores but there is no trace of parasites. Is it diet
related?
-------------------------------
SPOTTY MICE - OVERHEATING
Some mice (Only bucks in my experience, but it may happen to does too) develop
a food intolerance which results in itchy skin, sores and scabs over the back
and neck, and a generally miserable-looking mouse. If you are certain that he
does not have a parasitic infestation (lice, mites etc.. - you can't always
see them, so if in doubt ask a vet) then put him on this diet:
*Home-made mouse diet as described above - rice, oats/barley, vitamins if
required BUT NO millet or sunflower seeds.
*No corn/maize.
*Soaked staled wholemeal bread as above
*Plenty of carrot & other easily tolerated veg.
*AVOID wheat - don't substitute this for oats or barley in the molasses mix.
If the mouse does suffer from the food intolerance (known as 'overheating'
in the mouse fancy), the sores & itching should start to subside within 0
10 days. He will normally be left with scabs for another few weeks or so.
Allow 4-6 weeks for a complete recovery.
Angela King
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PARASITES & SKIN PROBLEMS
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4.1 My mouse has scabs on the back of his neck, scratches on his ears etc..
-----------------------------------------------------------------------------
This could be caused by a parasitical infection (commonly mites) or a food
intolerance (see above).
Mites tend to hang around in the fur behind the ears and on the nape of the
neck. So do the scabs from food intolerances, which makes things difficult.
Try treating for mites first. They are not always visible to the human eye,
but those which are look like small specks of dust in the fur (sometimes red,
sometimes moving). They are normally caught from hay or straw, other mice,
or infected feed.
Treat mites with dusting powder sold for cage birds. It is important that the
powder is sold for MITE treatment & not for fleas. Most bird powders
are Pyrethrum based & safe for mice. Rub the powder in with your fingers
(brushes seem to upset the mice) and repeat the treatment as often as it says
on the packet, or alternatively three once-weekly dustings should do the trick.
At the same time you need to treat any other mice sharing a cage with the
affected mouse or near it, and to thoroughly scrub out the cage & any toys..
If you have lots of animals then you may want to consider giving them all a
precautionary dusting with mite powder after every new arrival, or after any
attend a show or meet other animals.
Another very effective treatment for mites is Ivermectin. This is a medicine
which is great for removing stubborn parasites, but dosage is very important &
for a mouse it will be a *tiny* amount (since the product is manufactured
for cattle & other large livestock). So if you want to use this it really is
necessary to visit a vet and get them to check the required dose.
Other measures you can take are to sprinkle flowers of sulphur in the
bedding, hang a Vapona or similar insecticidal strip near the cage, and feed
the mouse garlic (crushed in its food, or squeeze the oil out of a garlic
oil capsule).
Obviously insecticides need to be used with caution, so don't exceed the
recommended dose of whatever you use & if you hang an insecticide strip near
the mouse cage then treat this as a short-term measure only - it might harm
the mice if left there permanently.
If the product you use to treat for mites does not cover lice as well
then it may be worth giving an additional treatment for this parasite.
Other mouse skin problems apart from these parasitical infestations and the
food intolerance probably need veterinary attention. In particular you might
see:
RINGWORM:
Bald areas of skin, sometimes crusty as well, which spread out
(often but not exclusively in a round pattern). Caused by ringworm,
which is HIGHLY contagious and can be very difficult to treat. Humans can
catch it too. See your vet at once if you suspect it.
MANGE:
Nasty parasite which lays eggs in the skin. They hatch into larvae which
wriggle around and cause terrible itching. Very contagious - again humans
can catch it (I caught it off a dog as a baby - the doctor didn't know what it
was, so eventually my parents took me to the vet who diagnosed it straight
away!). Again a case for immediate veterinary treatment if it occurs,
although I have never actually met anyone whose mice have contracted mange.
Angela King
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BREEDING
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6.1 How do you breed mice?
---------------------------
With caution! Most mice are very, very fertile - they have up to 17 babies
(called pinkies at first) per litter, although 8-10 is more normal. If a
pair are left together, they can produce a litter every 3-4 weeks; they do
not 'take a break' or plan their family. It is hard to find enough good homes
even for very pretty mice, so don't breed unless you're sure you can find
homes. Unless there is a fertility problem with a particular mouse, you can
expect it to conceive within a week of the male and female being placed
together. The female comes on heat approximately every 4-5 days, usually
overnight. The gestation period is 17-21 days, although mine have all taken
20 or 21 days. You cannot normally tell that a mouse is pregnant until the
last week of her term, when her belly starts to bulge.
When introducing the male and female, she should always be put
into *his* cage, and not the other way around - female mice can be very
aggressive to males who pester them, and even more so if the female is in her
own territory.
6.2 Should you remove the father before the birth?
--------------------------------------------------
Yes - but it is a myth that male mice eat their babies if left with the mother.
If the father is left with his family
(continuously - he has to be there through at least some of the pregnancy and
birth to accept the babies as his own) he will be an *excellent* father and will
take on a large part of the childcare. However, he will also mate with the
female immediately after she has given birth, and females bred continually
in this fashion are likely to become exhausted and to produce weaker
babies than those whose families are paced. So it is better to separate the
parents before birth, and to allow the mother 4 weeks to suckle her babies
plus another 2-4 weeks to rest before putting her with the male again.
The problem of what to do with the father is one you should think about
seriously before breeding mice. As mentioned above, unless you have him
neutered he will not be able to live with other male mice - but if you keep
him alone he will have a very boring life. If the female is getting adequate
rest between litters then he will only have her company for two weeks out of
every 10 or so. So unless you have several females to live with him in turn,
he will be alone most of the time. This is quite serious for a mouse, so
think through it thoroughly before buying a male to breed from. Alternatively,
you might be able to find someone who has a male mouse which already lives
alone, or one which is regularly used for stud, who would let your female
stay with him for a week or so to mate.
6.3 When can you breed from females?
-------------------------------------
Female mice can breed from the age of five weeks onward -
but a female bred this young will probably have her growth stunted by the
experience, and may produce weak babies,
so it is better to wait until she is 3 or 4 months old and fully grown.
6.4 What should I do when my mouse has a litter?
------------------------------------------------
As soon as she starts to look pregnant, make sure she is in a suitable cage.
It must have a secure nesting area which is free from drafts and preferably
enclosed - the darker it is inside the nestbox, the better.
When she has the litter you may hear squeaking. It is safest to avoid
disturbing her until the babies are 3 or 4 days old. Provide plenty of food,
perhaps some bread soaked in skimmed milk, lots of bedding, and keep her
somewhere quiet.
6.5 My mouse ate her babies - what happened?
---------------------------------------------
If a mouse is going to eat its babies, it will normally do so within the first
three days. After that they should be safe, but occasionally it can happen
later. Litters are sometimes eaten for any of the following reasons:
- it was the mouse's first litter, and she didn't know what they were, or got
carried away eating the placentas and mistakenly ate the babies too.
- the babies were born dead, or died soon after birth
- the mother was disturbed or felt insecure - maybe her nestbox was not
enclosed or dark enough, or she was in a noisy environment.
- the mother has a temperament defect which causes her to cannibalize her
litters even in ideal situations.
Generally eating a first litter does not mean that the mouse will eat later
litters. But if she eats her second litter, it is best not to try again; if
she does eventually manage to rear a daughter, she may well pass on her habit.
6.6 How do the babies develop?
-------------------------------
They are born looking like frozen prawns, in a very underdeveloped state. They
are hairless, blind and deaf. Usually they are pink, but some dark varieties
show pigment at birth. Over the next 3 days pigment cells come to the surface
of the skin and amrkings become visible. Hair starts to grow at about 1 week.
The babies start moving around more, and nibbling solid food, and opening
their eyes, from about 10 days. Soon after this they enter the 'flea' stage
when they are very hard to handle - they literally jump like fleas. Be very
careful if you handle them at all between 10 days and 3 1/2 weeks of age.
Between 3 and 4 weeks of age they calm down. At 4 weeks they should be fully
weaned from the mother's milk. At 5 weeks, males and females should be
separated and they are ready to go to new homes.
Angela King
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