As strange as it may sound, the Rat Terrier is actually in danger of breeding itself out.
Originally brought over by migrant British workers in the 1920s, the Rat Terrier was made famous by its tiny stature, its seeming ferocity and its fleet-footedness. Some of them worked as vermin control, eradicating rats from farm lands and ranches. Others became excellent hunting companions, going after small game like hare, squirrels and wild fowl.
This breed of dogs reached the peak of its popularity between the 1920s and 1940s. It was so popular in fact that almost all farm lands and all ranches in the US had one or more Rat Terrier patrolling the landscape. They served multiple duties like sentry or watchdog duties, hunting companion duties and vermin control. Others became a mite too small to do anything useful in the farm or ranch that they became household staples as pets or toy dogs.
Unfortunately, the Rat Terrier population plummeted in dramatic numbers in the 1950s, brought about by the widespread use of chemical pesticides in farm areas. Some farmers during this time decided to keep using chemical pesticides to eradicate the vermin in their land instead. They rid themselves of their Rat Terrier pets.
This drastic move actually contributed to the Rat Terrier's breeding programs almost coming to a grinding halt. By simply refusing to take care of more Rat Terrier pets, or refusing to let their pets breed, the farmers helped cull even further the dwindling number of Rat Terriers. Other Rat Terriers that were allowed to breed were no longer closely monitored and had eventually bred their offspring into the mutt line. Also, the Rat Terrier turned out to be poisoned or allergic by the sudden rush of chemical pesticides and many sub-species never recovered.
Another reason for the poor dog population was liberal breeding. Through the years, liberal breeding to improveŁthe stock of the Rat Terrier has led to DNA contributions from Beagle, Chihuahuas, English White Terriers, Italian Greyhounds, Manchester Terriers, Miniature Pinschers, Smooth Fox Terriers and Whippets.
This practice of bringing in new DNA strain is actually helping wipe out the bloodline strain of the Rat Terrier. Careless commercial breeding of the Rat Terrier have led to a series of terrier like dogs that do not conform to any breed standards. Basically, these crosses and mixes are producing mutts. Others have successfully transcended the Rat Terrier breed and have established a separate line of their own.
One successful off-shoot of the Rat Terrier bloodline was the Teddy Roosevelt Terrier. Named after U.S. President Theodore Roosevelt, this strain or more specifically the Type-B Rat Terrier was officially listed in the UKC as the Teddy Roosevelt Terrier in 1999.
Another successful off-shoot was established in 2004, when a strain of hairless Rat Terrier was finally acknowledged as a separate breed by the United Kennel Club or UKC. It was called the American Hairless Terrier, or the Hairless Rat Terrier. The entire breed, in reality, came from one single Rat Terrier female dog that suffered from a form of hairless mutation, and was allowed to keep its unique trait until it propagated itself into a whole new breed line.