A terrier is a dog of any one of many breeds or landraces
of terrier type, which are typically small, wiry,
very active and fearless dogs. Terrier breeds vary
greatly in size from just a couple of pounds to weighing
over 70 pounds and are usually categorized by size
or function. There are five different groups with
each group having several different breeds.
Different localities raised terriers suited to their
hunting or vermin control needs. Terriers were crossed
with hunting dogs, fighting dogs, and other terriers.
The gameness of the early hunting terriers was exploited
by using them in sporting contests. Initially, terriers
competed in events such as clearing a pit of rats.
The dog that was fastest in killing all the rats won.Terriers
range greatly in appearance from very small, light
bodied, smooth coated dogs such as the English Toy
Terrier (Black and Tan), which weighs as little as
2.7kg (6lbs), to the very largest rough coated Airedale
Terriers, which can be up to 32kg (70lbs) or more.