Mouse twitching

Question
QUESTION: Hi Panya

I have a female mouse who is about 12 weeks old, she is very active and
inquisitive but does this thing where she sort of twitches but quite violently
so she ends up jumping around her cage, she looks like she been stung or
something.

It tends to happen after she has been out of her cage for a while or when she
goes ionto her newly cleaned out cage for the first time. The best way I can
think of to describe it is like she's got too much energy and can't control it. It
usually calms down after 15-20 mins but sometimes can last longer, even
after she's been asleep and gotten up again. If she does something like
chewing cardboard or grooming it seems to stop for a while (almost like if
she's concentrating on something else it doesn't happen)

She also grooms herself alot, (I think, I'm not massively sure what normla
levels are), not specifically in one place that I've noticed (although scratching
maybe behind the ears a bit more than anywhere else) her coat is very shiny
and soft and I've checked as best I can for mites or anything and can't seem
to see anything in there.

Do you have any suggestions as to what's causing the twitching? Could it just
be overexcitement from being out of her cage? I don't know whether I should
worry about it as she seems fine and healthy other than that

Thanks for your help
Jo

ANSWER: It may be the cleaning product you use on the cage, any strong cleaning product such as bleach can irritate a mouse's sensitive skin. Also any strong-smelling cleaning product may distress a mouse. I use fairy liquid or sometimes just water if the cage isn't very dirty.

It may be excitement, a new cage is fun to investigate. However, the violent twitching isn't a normal part of their behavior.

It is good she has a shiny coat, this is a sign she is healthy. Mice groom themselves and each other a lot, especially after being handled by a human as they want to get rid of that 'human smell'.

Make sure she has plenty of things to do in the cage, such as a wheel, cardboard to chew one, tubes etc. If she is kept alone her erratic behavior may be due to stress. Mice are social creatures so she must have a buddy or two.

Please feel free to ask any more questions, I hope she calms down soon.

---------- FOLLOW-UP ----------

QUESTION: Thanks for your feedback Panya. I don't use any strong cleaning products on
the cage so I don't think it's that. It does seem to be particularly bad when
she goes back into a fresh cage which is what makes me think it's
overexcitement or nervousness. I noticed today her tail also vibrates (she
happened to be sat near the edge of the cage after I'd cleaned her out) it was
like a speeded up wagging or spinning. I'm just not sure how worried I should
be about it? It's quite unnerving to watch and abit scary when it's at it's worst
and I'm not sure if there's anything I can do to help her calm down? I'm
scared she might hurt herself.

She is on own at the moment because she was the last one of her litter left
but I do want to get her a friend. Do you have any tips on how to introduce a
new mouse to her? I'm worried she might be a bit old and also if the twitching
thing is some sort of illness rather than a condition, that she might pass it to
the new mouse. She's never seemed particularly aggressive with me, only
slightly nibbling if she can smell food on me but I don't know if that will
translate into other behaviour with other mice.

Any advice you can give me would be greatly appreciated
Thanks for your help

Jo

Answer
The vibrating tail is when they mark their territory with urine. It's perfectly normal and nothing to worry about. This explains her behavior as she is excited but also on hyper-drive so she can mark 'the most' territory. I really don't think its an illness or anything to be worried about.

I think she will calm down once she has a friend. Females are easy to introduce. Ask the pet store to show you mice who have had litters in the past and have made good mums. Find one you like and is easy to handle (preferably the same size and age but not essential). They will send her home in a cardboard box with air holes. Keep an eye out for her chewing her way through the air hole (I had a mouse escape through the air hole by chewing around it - it worked out OK though). Place the box in your mouse's cage which is around 3 days old since you cleaned it. Let the new mouse come out and investigate in her own time. Keep the cage in a room with no bright lights and watch them for a few hours to make sure they don't fight. There may be some squeaking as they get to know each other but that's normal. If there is any fighting or if either mouse looks distressed you should separate them. Females don't usually fight and you will find most will get along with each other.

Your mouse shouldn't be nibbling even if you smell like food. It is important you handle the young from around 3 days so they get used to your smell and being handled by humans and this behavior is not passed on to the babies.

Please feel free to ask anymore questions.