Working terrier

A working terrier is a type of terrier dog bred and trained to hunt vermin including a badger, fox, rat and other small mammals. This may require the working terrier pursuing the vermin into an underground warren. These working dog breeds are neither bred primarily for a dog show nor as a companion dog, rather they are valued for their ability to hunt, endurance and gameness. Working terriers provide utility on farms, for pest control and organized hunting activities. A terrierman leads a pack of terriers when they are working.

According to the Oxford English Dictionary, the name terrier dates back to 1410 in the writings of Edward of Norwich, 2nd duke of York (1373 – 1415). The word terrier in Old French derives from the Latin terra, which means "earth". The term terrier meaning "earth dog" or "dog of the earth" was used in the Middle Ages with the connection to the dog’s role of burrowing into the ground in pursuit of quarry, which eventually became the name of this group of hunting dogs.

With the growth in popularity of fox hunting in Britain in the 18th and 19th centuries, terriers were extensively bred to follow the red fox, as well as the Eurasian badger, into their burrows. This is referred to as "terrier work" or "going to ground". The purpose of the terrier is to locate the burrow of the prey animal, and then either intimidate it into leaving its burrow or hold the prey still so it can be killed or captured.

Working terriers can be no wider than the animals they hunt (chest circumference or "span" less than 35 cm or 14 inches) in order to fit into the burrows and still have room to maneuver.

Terrier work has been condemned by British animal welfare organizations, such as the League Against Cruel Sports, the International Fund for Animal Welfare, and the Royal Society for the Prevention of Cruelty to Animals, because it can lead to underground fighting between animals and cause serious injuries. The British National Working Terrier Federation denies that underground fighting is an issue, arguing that the terrier's role is to locate, bark, and flush out the hunted animals, not to attack them. Hunting below ground with terriers is largely illegal in Britain under the Hunting Act 2004, unless conducted by strict conditions intended to protect game birds. Hunting with working terriers for rats is legal in the United Kingdom. Terrier work is legal in Australia, Canada, South Africa, the United States and much of continental Europe.

The primary characteristic for a working terrier is that it has an owner or keeper who works it; a terrier is not a working terrier by virtue of its breeding alone.

The second most important quality of a working terrier is small chest size. Though the ideal chest size of a working terrier may depend on the size of the den pipe, smaller dogs generally do as well as or better than larger dogs. A small dog can get to the quarry without having to dig and arrives at the quarry without fatigue. Dogs that are too large will struggle to get past curves in the tunnel and will have to be dug every few feet. If a dog has to dig deep enough to where the tunnel tightens down, the dog will have to push dirt behind it to progress, which can result in the dog being "bottled" by dirt from behind. In such a situation, the dog will have a difficult time getting out on its own if it cannot turn around.

With two animals underground, a flow of air must be maintained to avoid asphyxiation. The more space a dog takes up in a burrow, the more the airflow will be constricted. In addition, a small dog has better maneuverability and can more easily avoid being bitten. Because of this, small dogs often receive less injury underground than larger dogs, which are more likely to find themselves jammed in a den pipe, face-to-face with the prey, and unable to move forward or backward.