Hi there, I have two guinea pig boars, Joe, and Jack. Joe is the more dominant, Jack is a bit scared of everything still. Well I noticed today Jack had a bit taken out of his ear, and I wondered if Joe did it. But they are siblings and when I put them together are very happy to see each other. So do you think Joe did it? I need to know, I don't want a bossy or violent guinea pig. Thank you!