Terrier Group dogs tends to have very distinctive personalities. These are feisty, energetic dogs whose sizes range from fairly small to the quite large. Terriers typically have little tolerance for other animals, including other dogs. Their ancestors were bred to hunt and kill vermin. Many continue to project the attitude that they’re always eager for a spirited argument. Most terriers have wiry coats that require special grooming known as stripping in order to maintain a characteristic appearance. In general, they make engaging pets, but require owners with the determination to match their dogs’ lively characters.