Totally agree with pinkbunny. We have Staffs as well, and although they're fabulous with people, they aren't so good natured with other dogs, because of their breeding, but ALL terriers were originally bred to hunt. The bitches seem to be the worst in my opinion, and were the preferred sex for use during bear fights. We had ours properly trained, and feel very at ease with them around our children and their friends, but if out where there's a liklihood of them coming into contact with other dogs, we have them muzzled and on a lead. Sorry to hear about your dog getting hurt though, and no dog should be allowed in a play area.