Even though wildcats inhabited Europe for centuries, they could not be domesticated. Consequently they were hunted to extinction. It was up to the dog breeders to develop a canine that was well suited to the task of hunting and killing rats. Many of the smaller breeds, like the rat terrier are well known rat catchers. A lesser known breed called "feist" was even smaller, but made up for it's lack of size by being quick, tenacious and fearless.
It wasn't long before the term feisty was being applied to certain kinds of people--if you know what I mean.