You've probably already seen this trailer. It's hit the internet in a big way. While the actions of Tara the cat surprised a lot of people, I doubt if it surprised many cat folks. There are a lot of cats out there that take people guarding seriously.
When I lived in IN a burglar broke into a woman's house that lived alone. The cat didn't bother the man until the burglar started upstairs where the woman was sleeping. At that point, the cat attacked. The burglar escaped but left a trail of spattered blood behind him.
Homer, a blind cat, woke his keeper by growling and hissing. The woman found a strange man standing at the foot of her bed. While he was distracted by the cat, she called 9-1-1. At that point, he turned and ran out with the cat in pursuit.
A Texas woman was attacked by two pit bulls. Her cat launched herself into the fray, giving the woman's husband time to get his wife to safety.
And on the home front: Years back, I was trying to get my declawed cat in the house because a big dog was running loose. I got him in the house and then before I could get in myself the dog jumped on my back. I really don't think he would have hurt me, but I'm sure both animals could sense my fear. The cat came hurling out of the house and ran the dog off.
Another time: When our daughter was two years old, she'd wandered out into a cornfield. The hh was frantic, he called and called but she wouldn't answer. Luckily, Bruce (the declawed cat) stuck by her side like glue. Every time my husband called for our daughter, the cat meowed. And that was how he found her. We were young and stupid and shouldn't have let a declawed cat outside. But it never slowed him down. He climbed trees and attacked dogs. He rode several out of the yard.
When it comes to man (woman or a child)'s best friend, dogs have some serious competition.