My wife and I got a dog from the shelter about six months ago. He seems to be a Jack Russell Chihuahua mix about two years old and he's pretty skiddish. He's very affectionate but definitely has some issues. For example if people high-five in front of him he starts barking and acting a little aggressive. He'll bark and jump up and down but has never gotten truly aggressive until tonight.
He was in his kennel and eating a treat when I walked over and stood in front of his cage. He immediately started guarding the treat and growling aggressively. I hear my wife say that I need to correct his behavior so I yelled his name (Probably not a good idea, I know) and yelled "stop" while I slammed my hand on the cage.
I know my reaction was not the correct one. It was a bad instinct and all I can say is that I was extremely surprised by his reaction and my first instinct was not the correct one.
In any event, his reaction was to attack and he bit me several times. I have several fairly deep puncture wounds on my forearm and my jeans were ripped so I knew he bit multiple times.
My wife and I are not sure what to do at this point. When we adopt a dog, it's a lifetime commitment for us but we're also planning on having kids soon and I refuse to put them in unnecessary danger.
Any advice would be appreciated. Is this something that patience and training can conquer or is there any truth to the "once a biter, always a biter" expression?