When my kids were growing up, we h ad an enormous black Great Dane, and his name was "Mr. Spock", since he had pointed ears. He was an awesome dog, and he totally guarded the house, and watched over our kids.
Anyone coming in the driveway was met by Spock, who let out a few loud woofs at them. That would usually keep people in the car until one of us went out to welcome them.
Spock was actually a very friendly dog, and he enjoyed visiting and getting petted when we had company; but we never worried about anybody stealing anything when we were gone into town shopping.
We only had a little house, so when Mr.Spock was in the house, he took up a lot of room, but he would usually lay down out of the way. At night, he slept near the door; and he seemed to know that protecting the family was his job.
