Mating Mice

Question
Hi, I am doing a research project on mice and I have to mate them(don't worry the mice will not be harmed in any way during this project, they are treated as part of the family)I put them together on monday night of this week and he was chasing after her and smelling her in her "area" and he was even trying to mount her. She sqeaked at him and would kick him away which I think is normal. They did that all throughout the night because she kept me awake with her sqeaking. well the next day he sniffed her a little but did not bother to try and mate with her anymore. Do you think they mated while I was sleeping or did she go out of heat and he missed the time to mate with her? I plan on keeping them together for two weeks to ensure that she indeed does become pregnant if she's not already. After two weeks I'm going to take the male out so that she will be able to have her babies without him bothering her and so he does not mate with her again. I know that back to back mating is not healthy for the female or the babies. Also, I noticed that the male mouse is the main one to make the nest. He fixes it up whenever they go in and out of it, she does help a little. Is this normal? Shouldn't she be the one making a nest? I also noticed that they clean eachother a lot and when they are sleeping she will lay right on tope of his whole body. Is this normal for them to do? Sorry for making this so long. I hope you can help. Thanks.

Answer
Thanks for taking the time to ask me and for using allexperts.

Answer to your questions:
With mating any rodent it usually takes one 3 sec go and your done. It is over and done with. However, the male may try over and over just because...well he is male. And it is okay to leave him with her for either the two weeks that you are wishing to do with your project or till the babies are weaned. Rats will not eat or mess with the babies just dont disrupt the moms nest and clean around it.

As far as the nest goes most females make a nest for the babies, but males also make what we consider a nest and it really just them making themselves a bed. However, whom ever makes the nest make sure to provide materials they can use. Here is list you can kinda go by.

toilet roll
new dishcloths
cardboard
hay
old (clean) socks
pieces of fabric
leaves
grass
box

Last the cleaning.  Mice are social animals meaning they like being in groups. Just like other animals cleaning is a "friend" type activity. Just like playing or eating together they will clean one another. As long as they are not doing anything to hurt one another like making marks or drawing blood then it is typical of mice.

I hope that your project goes well and here are some sites that may help you:

http://www.ehow.com/how_2046523_groom-pet-mouse.html

http://knockout.cwru.edu/services/musfrming.html

http://www.sialis.org/mice.htm

http://www.natureprotocols.com/2006/08/24/assessing_nest_building_in_mic.php