It's in the blood
Jessie loves nothing more than to hunt critters. Jack Russells were originally bred to hunt foxes with their owner and anything else that moved. They were kept by many to keep vermin away from the farms and their ability to hunt and kill small animals is not to be matched. The Jack Russell and the Fox terrier were once the same dog. One dog and a fork in the road, one Jack Russell continued down the working road and the other down the opposite road slowly evolving through dog shows into the Fox terrier of today.
Terriers in general are a tenacious group; and until you have had a terrier of "true" temperament you cannot fully understand these little dogs. Just yesterday as I was walking my poodles in the park I passed a gentleman with a Scottish Terrier. Each time we walked past him he veered off of the path and distanced himself. The last time round the park I shouted to him "feisty scottie eh?" He grinned as I told him that I had a Jack Russell Terror at home and fully understood.
This morning I took Jessie over to the school for a run; she loves it. The entire time she is in the "zone." Her body posture oozes that she is "on a mission." She is on high alert as the squirrels (stupid that they are) alert her to their presence. She knows she cannot catch squirrels but every once in a while she will charge one; you can see her beaming. You simply cannot see more joy in a dog than a Jack Russell hunting for critters.
We walked the school yard where all the rats hang out; yes rats. I was mortified the first time I saw them but it is a fact of life; there are lots of rats around here. And Jessie's favorite subjects to hunt are rats. She can smell their little footprints everywhere but it is only when she knows that they are actual present that she goes into crazy mode. Today she found a fresh scent in a sort of underground drainage thing; it had a steel plate running over it with gaps every so often. She checked each and every gap and soon knew exactly where they were. With her tiny little legs she attempted to extract them from their hiding spot; we moved on.
By the time she is done her walk she is exhausted; I know she barely realizes that I've been with her the whole time. I love letting her do what is in her blood, it is what makes her tick. She is afterall a Jack Russell Terrier.