Dwarf hamsters fighting
I have two winter white dwarf hamsters, Buttercup and Wesley. They're probably about three months old or so. (I got them on Father's Day.) Buttercup had babies about two and a half weeks ago (they were two weeks on Saturday). However, starting on this Sunday, he began to try to mount her. She said no and I figured it was okay even though he tried a few times. But they began fighting, just little quarrels, which generally ended with Wesley on his back and squealing. She hasn't stopped fighting him. Now, his bottom is kinda wierd (it's dark, like it was bruised badily, and a bit hard but it feels more like it is crusty. His poo and everything look fine though.), he doesn't trust her and they are still fighting for no apparant reason. When I took him out of the cage for a few hours and put them back together on the table, everything was fine and she ignored him. But once back in the cage, she let him say hi to her but they are still fighting.
So,1) Any ideas on how to keep them from fighting? I'm worried she's going to hurt him.
And 2) Any ideas on what could be wrong with WEsley/if I should worry that he is hurt?