Terrier dogs were originally bred to hunt and control vermin and other predators such as rats, mice, foxes and ferrets. This selective breeding for specific characteristic and traits gave rise to small, energetic breeds with very determined temperaments. Terriers were bred for their ability to dig tenaciously in search of their quarry as well as the tendency to bark persistently in order to frighten their prey out of hiding.
Terrier dogs tend to be small or medium in size and are usually described as feisty, willing to take on even the biggest of opponents with no regard for size. This is an excellent trait for hunting rats, but it’s not always a nice attitude with other pets or young children.
The very traits that make them successful hunters can also make them a little difficult to train effectively as their determined nature may seem to some as being stubborn.