That is so funny. Pets end up doing the opposite of what you'd expect.
When we got our female mutt ( black and white rescue), our 1 year-old male (rescue) was all rough and tumble with her. By the time she got to six months old, she was standing up for herself and giving it back at times. Now, at 3, she is taller, stronger, and way faster than he is. He will still play with her, growling and biting on her legs. Usually, she just lays down letting him bite her leg (playing) growling, sometimes spinning her around like a pro wrestler move. Big tough guy.
RIGHT. She absolutely loves her big brother.
But, when she wants to show him who is boss, she can. She is the ALPHA. Often, when we come home from walks, she will run into the driveway ahead of him and turn around with this goofy smile. She becomes a football player on the line of scrimmage and she will not let him past. They will growl and bare teeth as she chest butts him back on his butt, but he can't get past her, -unless she lets him. Sometimes he will head-fake her like he isn't interested and then he runs as fast as he can, but she catches him -if she wants to.
They are best buds for life.
2lbs of hell on wheels 
