I have two males who are brothers. One is trying to mate with the other. Is this "normal"? Should I separate them? Are they going to hurt one another or even kill one another? They are between 18 and 24 moths old.
This is a display of dominance. Often it can be pretty mild but it can turn bad pretty quick. If they are balled up fighting, you need to seperate them. I would suggest getting both boys neutered. This will decrease their hormones and make them less aggressive and dominating. It will also reduce their odor and reduce their risk of certain cancers.