Welcome to the American Mammoth Jackstock Registry, the original registry of official pedigrees for American Mammoth Jack Stock.

The registry was established in 1888 as the American Breeders Association of Jacks and Jennets. A second registry for Jack Stock was later created, the Standard Jack and Jennet Registry of America (SJJR). In 1923 the two entities merged, and the registry was known as the Standard Jack and Jennet Registry of America (SJJR) until 1988.

In the late 1960's, the American Donkey and Mule Society was founded, and subsequently adopted "standard" as a descriptive term for that organization's category for donkeys of a particular size range.

In the years that followed, confusion grew due to the similarity of the American Donkey and Mule Society's "standard" donkey category, and the word "Standard" in the Jack Stock registry's name: Standard Jack and Jennet Registry of America.

Though "Standard" in Standard Jack and Jennet Registry of America referred to a standardized breed--animals with the particular characteristics that comprised a breed standard, SJJR was often incorrectly perceived by many to be a registry for "standard" donkeys--donkeys that were of the size defined by the American Donkey and Mule Society's category of "standard" donkeys.

To end the "standard" confusion, the name was changed to American Mammoth Jackstock Registry (AMJR) in 1988.

At AMJR we are committed to maximizing the resources of the registry to provide comprehensive, expedited registry services to Jack Stock breeders, owners and enthusiasts while striving to preserve the heritage and integrity of this unique American breed.

The rich history of American Mammoth Jack Stock: the development and unique qualities of the breed, combined with their vital role in the early development of  our country is well documented in the records of AMJR. Through an increasing effort to expose this little-known part of America's cultural history, AMJR is dedicated to perpetuating Jack Stock for the enjoyment of future generations, and gaining broader recognition for the breed's historic significance.