[Maximo]

Aggression is not a characteristic of male Yorkies in general. What kind of behavior are you seeing that concerns you?

Yorkie puppies in general can be feisty. Puppy litters often play rough with each other and learn from their moms and littermates when rough is too rough. Your boy is very young at 8 weeks and still testing boundaries.

There are also differences among pups/adult Yorkies. My older boy has always been more polite toward other dogs, whereas my younger boy likes to play rough. He is a little sweetie pie, but a bulldozer when playing with his thankfully patient older brother.

When you see him getting rough, redirect his attention. I always break up rough play with a correction and then redirect to performing a few tricks for treats, or a short game of fetch.

Make sure your girl has a place to escape the puppy when she wants. Work on trick/obedience training with your puppy. Never too early to start the training. Separate them when you can supervise. We kept our boys in the same room, but put the younger in an xpen. We had 2 xpens hooked together so that he had more room. Or you can use a babygate to separate if you have a suitable area.