Here are a few commonly asked questions about Rat Terriers.
A Decker or Decker Giant is a large, terrier-type dog developed in the 1970s from the Rat Terrier owned by Milton Decker. His goal was to develop a quality hunting dog. Though the strain shares many similarities with the standard and miniature Rat Terriers, the type is outside of the weight requirements specified in the breed standard. The AKC does not recognize the Decker, but the National Rat Terrier Association maintains a Decker Hunting Terrier Registry. A Decker Terrier is not simply a large version of the Rat Terrier—in order to register, a Decker's bloodline must be traced to the original Deckers bred by Mr. Decker.
The American Hairless Terrier is a hairless terrier-type dog developed when a Rat Terrier without hair was born in a litter of otherwise-coated puppies. The owners of the hairless puppy decided to develop a hairless Rat Terrier, which led to the creation of the American Hairless Terrier. The hairless gene in this dog is recessive, which distinguishes it from most hairless breeds with a dominant hairless gene. This means that some litters may produce puppies with coats, as well as hairless puppies. In order to prevent health concerns and issues related to inbreeding, hairless and coated varieties may be bred to maintain a vast gene pool. Hairless/hairless pairings produce about two out of three puppies without hair, while hairless/coated pairings produce an average of half coated and half hairless.
Rat Terriers are born with erect ears that droop around the same time their eyes open. Their ears may then stand erect, or remain semi-erect or tipped, or fold over in a button carriage. Ear carriage may not stabilize until the dog reaches adulthood.