Hi I have adopted a female and male Jack Russell, sister and brother but they keep on fighting. It seems that the male wants to play (maybe to rough) but the female then starts to get aggressive and bites him. He is very dominant and throws her to the ground. He is much sronger and bigger than her. We have not had any blood but I am conserned. They are only 8 weeks old. I have also noticed the male "humping" the female? I dont understand they are just puppies and we cant have them neutered till they are 6 months. I could use some advise please.