My cat defends my son during a vicious dog attack and runs the dog off before he can do additional damage. Thankfully, my son is fine!

Question: Why did the mom run away? 
Answer: After checking his wounds she made sure the dog did not return for a second attempt. The owners were there also and she was bit by the dog as she tried to pin him in his yard. The owners did get control of the dog and secured him in which she immediately returned to attending to our son. I did not include that video because it was not so much about the dog but about the cats actions.

WHAT THAT HAVE TO DO WITH A BJJ RELATED WEBSITE? Nothing, but that is a pretty cool video of a small cat being able to defend his "family" against someone bigger and more dangerous. Very much like Brazilian Jiu-Jitsu!