Spanking

I don't spank, but if I did I would have yesturday. The neighbor kids came over and Travis tends to be territorial when their here. I was chatting with my friend in the kitchen when I heard the scream. Turning a 180, I saw the little girl next door grabbing her face whilst screaming, "Travis eat me!! Travis eat me!!!" She pulled her hand away to reveal a rapidly forming purple circle covering bits of her cheek, eye, and forhead. Judging Travi's determined face, he was mad and definitely the predator in Jacie's victimhood. As the deepest teeth marks I'd ever seen (even including Thomas's through the shirt bite) began to form, Travis recieved a 2 minute time-out from a mother with a quivering lip. I was really upset, but not so much as Jacie who was still grabbing the left side of her face in agony.
I've tried everything to get him to stop bitting. I fear Travis was born with a bit a fire which, cultivated properly, could lead to his advantage in life I'm just not sure if I'm going about it the right way. Any pointers would be appreciated:)
P.S. Maia and I had to stop ourselves from cracking up while Jacie explained to Travis very calmly that she quote: "Did not want be his dinner."