Suppose you were given the job of creating the world's greatest early warning system.
Some of the requirements might look like this:
- Multi-modality sensing....optical, vibration, volatile organic compound sensing
- Vibration sensing finely calibrated to discriminate between events/non-events
- Modest initial purchase
- Inexpensive maintenance
- Insensitive to weather
- Self directive
- Able to work alone or with others
- Willing and capable of attacking marauders
- Provides entertainment when off-line (like a smart phone)
Small landholders in Europe had a need for the Swiss Army Knife of dogs. It had to be small enough to feed economically. It also had to be small enough so it did not arouse the King's attention regarding poaching. It had to be quick. It had to be inquisitive and self directed. In a fight with vermin it had to become immune to pain. It had to be physically robust and able to heal from a constant stream of wounds.
A thousand of generations of selection pressure led to a type of dog. That type showed up in many different places in Europe because the selection criteria were so similar. That type is known as a terrior.
Vermin are characterized by scratching and gnawing sounds. These dogs go ballistic when they hear that. The scrape of a jimmy or a screwdriver are very similar to those gnawing sounds or the fox attempting to dig its way into the henhouse in terms of rise time and harmonic content.
These small dogs have a hyperdeveloped rage reaction. They clamp on and shake. They are single-mindedly beyond pain. They will prevail.
They have no fear of the dark or of confined spaces.
Many rural properties in the United States look much like those prototypical, European small land holdings. It should not be surprising that the dogs that were optimal for Scotland, England and Germany can very comfortably fill niches in Virginia, Kentucky, Michigan, Texas and Oregon. They are no longer the first line of defense against rodents but they still strike terror into the hearts of the footpad who seeks to pillage the farmstead.
The only caveat is that one should seek pups from working stock. Many breeders select primarily for physical appearance. A few select for performance.
I concede that physical characteristics impact performance. Four pound, hairless dogs do not do well in in barns during Michigan winters. However, the law of diminishing returns kicks in. An active, muscular, well haired dog of fifteen pounds can take a surprising amount of cold if it is out of the wind and has access to food and soft, dry bedding.
Examples of that size dog are Fox Terriers, Jack Russell Terriers, large Rat Terriers, Scottish Terriers and medium sized Beagles.
Give Terrierman a peak if this topic is of any interest to you.