Before you adopt a little Jack Russell of your own, you should first understand the nature of this type of dog to be sure you know what you're in for. It's important to know the typical characteristics he will likely possess, because although all dogs can be trained, some have an innate personality that no amount of training can necessarily change and that may not be to your liking. Interested in adding a JRT to your family? Here's a rundown of some important facts you'll need to know.