After its acknowledgment as a separate breed, it enjoyed a short time of popularity among cat breeders in the United States. By now, due to crossbreeding with other Rex types, this breed seems to have merged with the other more popular Rex breeds like Devon Rex or Cornish Rex.
According to some claims,Template:Which? the first litters of typically Oregon-Rex-like cats occurred in 1944. The first documented case of an Oregon Rex cat is traced back to a litter of cats in the U.S. state of Oregon in 1955. The specific kitten differed from its siblings and its mother by having a curly coat whereas the others all had straight fur.
At the same time, the first Cornish Rex were imported to the U.S. from Great Britain, and were soon interbred with the developing Oregon Rex breed. Breeders from Oregon then established a purebred Oregon Rex which soon became one of America's most popular Rex breeds. In the course of breeding, however, all types of Rex cats—each of which differ genetically—were crossbred, and the Oregon Rex did not endure as a stand-alone breed. The last purebred Oregon Rex cat is reportedTemplate:Who to have died in 1972.
The typical curly coat was silky, short and tight, and featured no or only relatively short guard hair. The kemp was shorter than the German Rex's or Cornish Rex's and was fully developed, with a typical subpical swelling. Their minimal flexion made the kemp hairs longer than the undercoat. The number of hairs was normal, but the bristles were missing.
The head was wedge-shaped with a long bridge. The ears were large with smoothly rounded edges and were set high on the head, and the eyes were medium-sized with an oval shape.
The Oregon Rex's body was of an elongated and tiny build, the tail was long, slim and peaked. The legs were long, gracile and slim, with tiny, round paws.
The Oregon Rex combined the character traits of all Rex breeds. They were affectionate and needy, funny and playful, sometimes a little turbulent, and a little arrogant. The Rex was also reported to have a dominant character and thus to be somewhat complicated to handle.
The origin of the Oregon Rex breed is a result of mutation. Mutations of the gene responsible for the typical curly hair or those genes involved in that process seem to be quite common. In addition to the other Rex breeds there are several other variants, the now-extinct Oregon Rex being only one of them.
Crossbreeding of cats with typical Oregon Rex features (genetic description: roro) and Cornish Rex (rr) and later with Devon Rex (rere) resulted in offspring with normal, non-curly coats. Research supported the fact that the Oregon Rex mutation represents a recessive allele (ro) of an own gene with the dominant wild type allele (Ro) and therefore was in fact genetically different from other Rex breeds.