We had a 1/2 Sheltie - 1/2 Border collie, who would sound a certain bark when an RV'er was at the door, a different bark when a storage tenant was at the door, a low growl, laying between a stranger and "The Warden" - and a severe growl, when the kids were involved!
Only person she ever bit was a "preacher" - the dog had GREAT instincts - he needed to be bit !!!!
