The dog we have at the moment is our second Jack Russell (our first one died in my arms when she was 17 years old).
They have this compulsion to race around the house to get to the letters that we have posted through our letter box every day and woe betide anything or anyone in their way - I've even tried to explain that the letters are not for them and even if they were, I would happily pass it to them. No, it doesn't matter to them.
Our current Jack Russell is about three years old and she will balistic at anything that passes our house including an ant trying to mind its' own business - I just totally despair.
Here is a photo of her from last Christmas.....
Her name is Eira which is the Welsh word for snow.
David