Description of a Rat Terrier.

The breed name comes from the occupation of its earliest ancestors; brought to the US by working class British migrants, these quick, tough little dogs gained their fame in rat pit gambling. However they were, for the most part, bred for controlling vermin and hunting squirrels, hare, and other small game. Like all terriers of this type, Rat Terriers most likely developed from crosses among the extinct English White Terrier, Manchester Terriers, Smooth Fox Terriers, and Whippets. After the 1890s, as the breed type became popular in America, other breeds were added to the mix. Beagle, Italian Greyhounds, Miniature Pinschers, and Chihuahuas were likely used to add scenting ability, speed, and smaller size. Many of the foundation Rat Terriers were indistinguishable from small mixed-breed hunting dogs known as "feists." The smaller varieties were split off from the Rat Terrier very early on, registered by the UKC as the Toy Fox Terrier beginning in 1936.

Rat Terriers were cherished as loyal and efficient killers of vermin on 20th century American Farms, as well as excellent hunting companions. As a result they were one of the most popular dog types from the 1920s to the 1940s. However the widespread use of chemical pesticides and the growth of commercial farming led to a sharp decline in the breed from the 1950s onwards. Fortunately breed loyalists maintained the bloodline, leading to the modern Rat Terrier we enjoy today.

The genetic diversity of the Rat Terrier is undoubtedly its greatest asset, and is responsible for the overall health, keen intelligence, and soundness of the breed. Most modern breeds were developed from a few founding dogs and then propagated from a closed gene pool. In contrast, the Rat Terrier has benefited from a long history of refinement with regular outcrosses to bring in useful qualities and genetic variability.