dog bit with no warning
pup is 8 months and is very very aloof to strangers. he is loving in the house to the family. on walks he ignores people. i've walked inches by children, joggers, kids riding bikes and he could care less. i've walked him off leash next to kids on bikes and random people and he doesnt even want to go over to sniff them. no reaction at all. he will tolerate being pet by strangers for a few seconds and then dodge their hand.
now with all that said; today my friend came over to pick up something from me. i opened the front door with dog on leash. the dog see's my friend coming up the drive way and doesnt even bark. i open the door and step out on the porch. now my dog is pulling and whining so i figured to let the dog sniff my friend. when he reached my friend instead of sniffing he jumped up and bit him on the stomach. it was more of a scratch than anything. no ripped clothes or bruises or anything but it definitely wasnt friendly. i immediately corrected and then the dog sat for a few seconds and then started whining and pulling again. he wasnt pulling hard as i was holding his leash in one hand and able to give my friend his stuff in the other hand. my friend left and the dog just went over to the front yard to take a piss like nothing happened. no barking, growling, or lunging. no hair standing up. no warning signs that i could see. people have been able to come into the house before. he's met people outside of our house before. when people come inside he will just whine and pull but he will just sniff them. what the heck was this? pure aggression?
i'm not looking for advice on how to deal because tomorrow i'm having a friend come over and if he puts his teeth on a stranger i am going to correct him hard. i'm just confused why he acted like this? extremely territorial? fear? the dog doesnt even bark at the mail man. i've never heard him bark at anyone in public. the only time he barks is when someone rings the doorbell or someone knocks.