They would fight. You should introduce them first, so that they can be used to each other. You can buy them young to let them get along. This is one of the easiest ways to solve this problem.
Some hamsters find it extremely interesting to see itself in a mirror. Some hamsters do think it is another hamster they are seeing, but get confused on how to reach them. Or your hamster may just like the edges and want to eat it.
You can't.
The hamster gets more exercise because he is pushing a ball. Plus it is easier to catch than the hamster itself.
It does not know any better.
What do you think? Of course not.
No. Hamsters aren't asexual.
If you can tell what your hamster looks like when it is cleaning itself you will be able to tell if it has fleas because it will be scratching itself more than you have ever seen it do.
A hamster will certainly escape and explore if it gets the chance. However a pet hamster's homing instincts are poor, and it is not adapted or accustomed to fending for itself in a human environment. It will most likely have to be recaptured before something happens to it.
If you have a wheel in its cage then the hamster will be able to exercise by itself otherwise I would get your hamster a ball and put him in it for at least 15 minutes a day.
When Mirena comes out by itself, you may be at risk for pregnancy. Use another method until you consult with your health care provider.
she is most likely rejecting it and you will need to immediately take the hamster away and care foe it youself until it is two weaks then it can care for itself.
The term for something that happens by itself is "spontaneous."