The Jack Russell Terrier and Napoleonic Issues
Most Jack Russells have a Napoleon complex. As often as he is top dog he can also get into situations where a larger dog will respond with extreme aggression, putting your Jack in real danger. It pays to closely supervise your Jack Russell when in the presence of other dogs. These Napoleon/Jack's often think they are as big as a full grown German Shepherd or Mastiff. It's likely a very good thing that they are not, a Jack Russell of that size would likely terrorize an entire neighborhood.
Egotistical and full of life seems to be one accurate description of the Jack Russell. A Napoleonic Jack will often exhibit territorial issues. They will often mark every inch of their property daily and take the protection of that territory very seriously. When another dog, no matter the size, approaches this Jack's territory he will immediately respond with a growl. When defending territory the Napoleonic Jack will also exhibit bristled hair along his back that will stand up straight and resemble a Mohawk; the tail will point straight up in the air; his head will lower, and his gaze will fix in a menacing glare at the intruder. The Jack will them begin marching forward, eyeing up the violator for a good spot to bite.
Very large breeds will often be shocked by this response and double take as if bewildered. The Jack often uses this state of surprise to further puff up and intimidate the intruder, often scaring off much larger dogs that would normally be more dominant. Some large breeds will be so surprised they will become submissive or flee for their lives in uncertainty. This is just another trademark of your fearless Jack Russell. If your yard is unfenced it is recommended to never leave your Jack out untied or unsupervised. Some dogs won't care how tough your Jack is.
Whether he is of the Napoleonic persuasion or not, your fearless Jack trying to dominate a large aggressive dog may land your little dynamo in some very serious, even fatal danger. Whether you are thinking about or already own a Jack it is wise to inform yourself and carefully consider all of the information available to you. As one expert has put it, just remember...he is Napoleon and YOU are Admiral Nelson. After taking all this Jack Russell Terrier information under consideration, and you know this is just the dog for you, there may be a little Napoleon waiting to make you a very, very proud owner.