With 2 beagles. All were single dogs.
My beagles were the biters. One would bite if he had something he shouldnt have and you were trying to take it away from him. My other - beagle/terrier mix - bit two of our friends he didnt know. I blame dad for a lot of his behavior because he would roughhouse with him all the time - pretend he was going to hit me or mom, let the dog chew on his hands, etc.
I had shepherds for over 18 years. The first one growled and bared teeth one time - a guy we met out walking at night (a water company supervisor who was overseeing a pump station fix). He put his hand on my shoulder and patted my back to assure me theyd be finished soon. She growled, he pulled his hand back and apologized. The other nipped a friend who didnt follow our instructions. Newly adopted, Halloween night, he was in a costume. We told him to ignore her and she would eventually come to him. He didnt do that. Came right to her and reached out with his gloved hand to pet her. She got his glove.
I miss my girls so much, but havent talked hubby into adopting again.