While he was a popular rodent catcher in Belgium, the Brussels Griffon was bred with other dogs. This produced three distinct variants of the Brussels Griffon. These variants are recognized as breed standards for the Brussels Griffon purebred dog in the United States, but in Europe, the three variants are seen as separate breeds. This is due to the physical differences seen in the dog due to the inter-breeding with other purebred dog breeds.
Brussels Griffon body types fall into three variants: the Brussels Griffon, or the Griffon Bruxellois, is red or a red-brown in color; some black can be found on his nose. His coat is wiry and quite long, longer than that of either of the other two variants. The Belgian Griffon, or Griffon Belge, is either black and red or black and tan in color. The black and red Belgian Griffon can have a black face mask but this is not necessary to live up to the breed standard. His coat is slightly shorter than that of the Brussels Griffon variant, but is still considered long and is also wiry. The Petit Brabancon is the short-haired variant; his coloring is either black or red, and he often has a black face mask accompanying the red coat.
The three variants of the Brussels Griffon are seen in two different lights. In the United States, the American Kennel Club (AKC) recognizes one breed standard, the Brussels Griffon. This includes all three variants of the dog and does not distinguish between them. According to the European Federation Cynologique Internationale (FCI), the three variants of the Brussels Griffon are all distinct and are therefore three different breed standards.
The Brussels Griffon has one of the most interesting deep genetic pools in the world of purebred dog breeds. He was originally bred with many different types of dogs, and this has led to much debate among Brussels Griffon enthusiasts about the true ancestry of the dog. There is also a lot of debate about which purebred dogs were bred with the Brussels Griffon to produce the breed standard we recognize today.
Many Brussels Griffon experts will agree that the Brussels Griffon definitely is descended from the Affenpinscher. This is because the dog is very close in resemblance to the Affenpinscher. The small size and fringed head of the Brussels Griffon in all variants mimics the Affenpinscher quite closely. There is some thought that the dog was also bred with Pug, which gives the Brussels Griffon his protruding eyes and gives the Petit Barbancon his short coat. Some people have theorized that the Brussels Griffon also has a descendant in the English Toy Spaniel and the King Charles Spaniel, though these are both highly argued and it is not certain whether both dogs were used, just one, or neither.