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.
Most terrier breeds were developed in Great Britain and Ireland. They were used to control rats, rabbits, and foxes both over and under the ground. Some larger terriers were also used to hunt badgers. In fact, the word terrier comes from the Middle French terrier, derived from the Latin terra, meaning earth. The Kerry Blue Terrier and Airedale, however, are particularly noted for tackling river rats and otters in deep water. Different localities raised terriers suited to their hunting or vermin control needs. Terriers were crossed with hunting dogs, fighting dogs, and other terriers. In the mid 1800s, with the advent of dog shows, various breeds were refined from the older purpose-bred dogs. All of today's terrier breeds are bred primarily as pets.
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. In the 1700s some terriers were crossed with hounds to improve their hunting, and some with fighting dog breeds to "intensify tenacity and increase courage". Some of the crosses with fighting dogs, Bull and Terrier crosses, were used in the blood sport of dog fighting. Modern pet breeds developed from the Bull and Terrier, such as the Miniature Bull Terrier, are listed by the Fédération Cynologique Internationale (FCI) under Bull type terriers.
Genetic analysis shows that most terriers are in the "modern/hunting" genetic cluster of dog breeds developed from the same pool of ancestors in Europe in the 1800s. A few terriers are found in the "mastiff" genetic cluster with Pomeranians, Labrador Retrievers, and other large-headed dogs, and the Tibetan Terrier is found in the older grouping of Asian and African dogs, along with the Pekingese.
Today, most terriers are kept as companion dogs and family pets. They are generally loyal and affectionate to their owners but can be "big characters" requiring a firm hand.
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.
The West Highland White Terrier is a small, game, well-balanced hardy looking terrier, exhibiting good showmanship, possessed with no small amount of self-esteem, strongly built, deep in chest and back ribs, with a straight back and powerful hindquarters on muscular legs....
The Miniature Bull Terrier must be strongly built, symmetrical and active, with a keen, determined and intelligent expression. He should be full of fire, having a courageous, even temperament and be amenable to discipline....
The Parson Russell Terrier was developed in the south of England in the 1800’s as a white terrier to work European red fox both above and below ground. The terrier was named for the Reverend John Russell, whose terriers trailed hounds and bolted foxes from dens....
The Bull Terrier must be strongly built, muscular, symmetrical and active, with a keen determined and intelligent expression, full of fire but of sweet disposition and amenable to discipline. ...
The Skye Terrier is a dog of style, elegance and dignity: agile and strong with sturdy bone and hard muscle. Long, low and level-he is twice as long as he is high-he is covered with a profuse coat that falls straight down either side of the body over oval-shaped ribs....
Aroused, the dog is particularly alert and full of immense energy and courage. Noteworthy for endurance, Bedlingtons also gallop at great speed, as their body outline clearly shows. ...
Long, but in nice proportion to the rest of the body; the skull flat, rather narrow between the ears, and narrowing slightly toward the eyes; free from wrinkle, with the stop hardly noticeable except in profile....
The Sealyham should be the embodiment of power and determination, ever keen and alert, of extraordinary substance, yet free from clumsiness. ...
The American Staffordshire Terrier should give the impression of great strength for his size, a well put-together dog, muscular, but agile and graceful, keenly alive to his surroundings. He should be stocky, not long-legged or racy in outline. ...
The Soft Coated Wheaten Terrier is a medium-sized, hardy, well balanced sporting terrier, square in outline. He is distinguished by his soft, silky, gently waving coat of warm wheaten color....
The Scottish Terrier is a small, compact, short-legged, sturdily-built dog of good bone and substance. His head is long in proportion to his size. He has a hard, wiry, weather-resistant coat and a thick-set, cobby body which is hung between short, heavy legs....
The Staffordshire Bull Terrier is a smooth-coated dog. It should be of great strength for its size and, although muscular, should be active and agile. ...