The American Kennel Club lists 30 different registered terrier breeds. Some of the most familiar are the Scottish terrier, Norwich terrier and miniature Schnauzer. Terriers range in size from the incredibly small Cairn or west Highland white terriers to the much bigger Airedale, the largest of the terrier breeds.
Terriers also come in many different colors and have varying hair lengths. Some terriers have very short hair, while the majority of breeds with longer hair typically have very wiry coats that require special care.
All members of the terrier family share many of the same personality traits, mainly an incredibly energetic and often aggressive temperament. Most breeds of terriers are quite confrontational toward all other animals, especially other dogs. Of all the breeds, the bull terrier, American Staffordshire terrier and Staffordshire bull terrier are usually considered the most aggressive and have gained a bad reputation for biting people and other dogs. These three breeds were originally bred as fighting dogs, combining the strength of a bulldog with the aggressiveness of a terrier.
Terriers were originally bred to kill rodents, digging holes to catch foxes, rats, badgers, moles and other vermin. Their love for digging holes is actually where they get their name, as the name "terrier" comes from the Latin word "terra," meaning earth or dirt.